BAD Mystery Shake / "Weird" Handling

[Carguy3J]

OK, first:
1993 Ranger 4.0L-OHV, M5ROD 5Spd, 4x4 (1354 manual)
Regular cab, Long Bed,
2 piece rear driveshaft (w/ slip yoke, but no center bearing)
3.73 limited slip rear
265/75/15 Cooper Discoverer AT3's on stock 15in aluminum wheels

I have been chasing a BAD shake/vibration for about 2 years now.
It is most noticeably right around 65-75mph, but it also can be felt at lower speeds (all the way down to 35-40mph). It kind-of smooths out a little bit over 80-85mph, but not really. It is always present, but it starts out at a much lower intensity, when the vehicle is cold. It is almost tolerable. After about 15-20 miles of highway driving, it gets really bad.

Also, it feels really "weird". I've even had a few shops take it for a ride, and they agree that something feels "off", but they don't know what. It kind of feels like the truck has a mind of its own, as though the rear is trying to steer the truck.

Also, when it really gets "going", the intensity of the shake will increase significantly when the truck is steered either left or right, vs straight ahead. (similar to how a bad wheel bearing might be quiet while going straight ahead, but get "crunchy" when turning).
It almost feels like a wheel hop, type of sensation.

I am reasonably certain that it coming from the right rear, or the rear at least.

Below is a list of everything that has been checked/changed:

Tires/Wheels: This problem existed with the previous, worn out tires, and continues unchanged with the new tires . I have had them balanced several times (including a "road force" balance) with no change. Rims do not appear to bent or out of round.

Entire front suspension has been rebuilt over the last 2 years, with no change: New front springs, new shocks, new ball joints/wheel bearings, axle shaft bearings (where the shaft goes through the knuckle), new spindles (both- Ford N.O.S.), complete steering linkage, steering box and pitman arm, rag joints replaced, new manual hubs, all new u-joints (axle shafts and front driveshaft), sway bar bushings and end links, axle pivot bushings and radius arm bushings replaced with Energy Suspension poly urethane

New motor mounts and trans mounts.

Rear driveshaft: New u-joints, new front slip yoke, had shaft professionally balanced.

Rear suspension/axle: New 4-leaf spring packs/bushings, new shackles/bushings "load-assist" shocks, new outer axle bearings/seals, carrier bearings, fresh & clean 75w140 Mobile one synthetic gear oil and one tube of friction modifier.

I've had multiple alignments done, as not all of this work was done together. Every time, it aligned with no problem. I'm using the Moog double-adjustable caster/camber bushings. The frame does appear, to the naked eye anyway, to not have any damage.

Every part that I have changed has been worn out and due for replacement, but none of them has made any noticeable change in shaking/ funky handling issue.

I'm about at the end of my rope with this thing. I've thrown everything but the kitchen sink at it, with no solution. Multiple shops have said they don't see anything obvious.

Here's what I'm thinking: 1.) A bent axle shaft, or bent housing, or 2.) Something in the limited slip is acting funny. Maybe, when everything heats up, the clutches are locking up or chattering? A locked/partially locked rear would explain the weird handling Any opinions on my ideas, or any other suggestions????????

:roll:

 

[Jstcruz]

My bro-in-law is facing similar issues with his 91. They rebuilt the rearend with new bearings and seals and didnt fix anything. This has been stuck in my head about his truck for a couple weeks, if they find anything I'll let you know.
As for any helpful input, a partialy locked diff wont make any noticable difference at high speed, or low speed for that matter, but turning sharply going very slow might show you something. Maybe try getting in some sand or gravle, turn the wheel extreme left or right and just let it roll slowly for a circle. see if the tracks from the back wheels are different. If they look different then your diff is locked up.

 

[Carguy3J]

My bro-in-law is facing similar issues with his 91. They rebuilt the rearend with new bearings and seals and didnt fix anything. This has been stuck in my head about his truck for a couple weeks, if they find anything I'll let you know.
As for any helpful input, a partialy locked diff wont make any noticable difference at high speed, or low speed for that matter, but turning sharply going very slow might show you something. Maybe try getting in some sand or gravle, turn the wheel extreme left or right and just let it roll slowly for a circle. see if the tracks from the back wheels are different. If they look different then your diff is locked up.

I actually tried that the other day. I don't notice anything, besides the usual squeaks and groans, when turning in a tight circle, at low speed.

I have to disagree though. A locked diff would be the same as a spool, and it would become much more noticeable at higher speeds. When trying to turn, any amount, the inside and outside wheels need to turn at different speeds, since they are following 2 different turning radii (plural of radius, not a typo.) If you try to make a high (or even moderate ) turn in a vehicle with a spool/locked diff, you will get binding and wheel hop. Trust me, you'll swear something big, important, and expensive just fell off and is laying on the ground in a puddle of various automotive fluids! This is why a Detroit Locker ratchets. It stays locked when going straight ahead, but as soon as you try to turn, it senses the torque bias between the 2 wheels, and unlocks so you can turn.

Now, a limited slip, like what I have, relies, at least in part, on centrifugal force to give the clutches their gripping power. Higher speeds equal more centrifugal force; so if I was getting clutch chatter, and/or intermittent excessive/unwanted locking action, it would be more noticeable at higher speeds. At least this is how I understand it. Any comments/corrections people????

On a side note, the problem is getting worse. It's getting scary. I also noticed that the right side axle shaft seems to have a bit too much in/out play. Yes I know there should be a little, but this seems excessive. On the other hand, the left seems to have almost none. What might cause excessive in/out play in the axle shaft? Worn/bent c-clip? Is it possible that I put the axle shafts back in on the wrong sides? There is nearly a 3" difference in the l/r axle lengths. Would they even fit in the "wrong" sides?

 

[Carguy3J]

Anybody else have any ideas? Please, let's hear 'em. I really need to get this figured out and fixed.

 

[4x4junkie]

1.) A bent axle shaft, :

This would be my guess (bent flange).

In/out play on the shafts is usually the result of clutch wear in a limited slip differential. Up to about 1/8" is fine, but more than that I'd swap a new clutch set in there.

 

[Carguy3J]

This would be my guess (bent flange).

In/out play on the shafts is usually the result of clutch wear in a limited slip differential. Up to about 1/8" is fine, but more than that I'd swap a new clutch set in there.

Yeah, I was kind of leaning that way, since there really isn't much else left to replace. The truck was fine 2 years ago, when I first started driving it, and something happened shortly after, to start all this. The local roads are like a mine field, and I routinely put 1500lbs+ in this truck, so a bent axle is a definite possibility.

The question is, do I spend the money on new 28-spline shafts, and the track-loc rebuild kit, or just buy a junkyard 31-spline Explorer rear? My concerns are 1.) Whatever was strong enough to bend the axle flange may have also bent the housing/tubes and 2.) If I bent a shaft once, it could happen again; so maybe I should just upgrade now.

On the "just fix what I've got side, I've already got quite a bit of money, in bearings, fairly recent brakes, and even $50 worth of new u-bolts, invested in my current rear, which I would lose if I swapped it out. I would also probably have to (or at least want to) do all that maintenance stuff on any used rear I bought, before installing. Plus, there is the additional expense of having the spring perches/shock mounts relocated. Of course, there is also the down time

Are the 31-spline axles (housing and shafts) really that much stronger, from a load-carrying and pothole slamming aspect (as opposed to rotational torque, which isn't really an issue)?

On the axle play issue:
There is definitely more then 1/8" of play in the right side axle. What is involved in rebuilding the track-loc? Any special tools needed, especially to deal with the spring? I've had several rears apart, and I've done bearings,etc... but I've never messed with the limited slip. Do clearances have to be set in the clutches, or is is just a matter of installing the replacements in the same order as what came out?

What symptoms would you expect to see from worn clutches, with the excessive play in the shaft (other then the loss of track-loc function)?

Thanks.

 

[4x4junkie]

What symptoms would you expect to see from worn clutches, with the excessive play in the shaft (other then the loss of track-loc function)?

Thanks.

Probably a heavy knocking noise when you go over speed bumps at an angle, etc. I'm not sure the thing can get so loose the axle c-clips would actually fall out (I would think the unit was designed to reach a fully-worn point and not go any further), but I can't swear to it.
Replacing clutches on a 8.8" IIRC is straightforward (not like on some 7.5s where you have to pull the ring gear off the carrier to get the side gears out). I seem to recall you also get a set of assorted-thickness c-clips in the rebuild kit. It's just a matter of installing the thickest one that will fit with the new clutches in place.

As for what bent the shaft, I think a lateral strike (like in a collision, or if someone took the truck and did a power broadie into a curb or rock or something) is much more likely to have bent it than overloading it. Overloading it can certainly affect the axle housing itself though (not to mention toasting the wheel bearings).

The 31 spline Explorer axle is stronger pretty much everywhere aside from the ring & pinion gears, and has a higher GAWR. It's up to you... Certainly it can't hurt anything to swap yours out for the Ex axle (well, other than your pocketbook).

 

[Carguy3J]

Probably a heavy knocking noise when you go over speed bumps at an angle, etc. I'm not sure the thing can get so loose the axle c-clips would actually fall out (I would think the unit was designed to reach a fully-worn point and not go any further), but I can't swear to it.
Replacing clutches on a 8.8" IIRC is straightforward (not like on some 7.5s where you have to pull the ring gear off the carrier to get the side gears out). I seem to recall you also get a set of assorted-thickness c-clips in the rebuild kit. It's just a matter of installing the thickest one that will fit with the new clutches in place.

As for what bent the shaft, I think a lateral strike (like in a collision, or if someone took the truck and did a power broadie into a curb or rock or something) is much more likely to have bent it than overloading it. Overloading it can certainly affect the axle housing itself though (not to mention toasting the wheel bearings).

The 31 spline Explorer axle is stronger pretty much everywhere aside from the ring & pinion gears, and has a higher GAWR. It's up to you... Certainly it can't hurt anything to swap yours out for the Ex axle (well, other than your pocketbook).

Well, I definitely have the "knocking" noise over bumps.

I'm not sure, but just suspecting, that the shaft/flange may be bent. Maybe not. It might all be in the diff? I do know that has been no "funny business" or curb shots since I have owned the truck. I'm the only one to drive it, so I know none of that has happened. However, I've driven into a few "pot holes from hell", and I;m sure I haven't always hit them straight on, so its possible the rear axle took a "side" shot.

In any case, after doing some research, I've decided that I just don't have the time, or money to deal with swapping to an Explorer axle. By the time I buy a used one, rebuild it, replace/refurbish all the brake parts/hoses, and pay a shop to weld up the perches and shock mounts, it would just be too much. Plus the time involved in doing all that......

By the time I buy all the parts to rebuild my existing L/S, including new side gears/shaft/shaft bolt,etc.., it's going to be close to $200, and I would still be stuck w/28-spline shafts

So, my plan is to buy a brand new, fully assembled carrier, which was OE in the '03-'04 Mustang Cobra, which I found for $250. It's ready to bolt in. I just have to swap over my ring gear, and install new carrier bearings. It has the upgraded carbon fiber clutches, and it's ready for 31-spline axles. I should be able to just stick it in, with my existing shims, without having to "set-up" the rear. Summit/Jegs both have a pair of new Moser 31-spline axle shafts for $260/pair. With the diff and shafts, plus bearings/fluid I should be able to have it all done for about $550-$575

I plan on ordering everything tonight, unless anybody has any reasons why this would be bad idea???? I'm thinking that the extra strength of the 31-spline shafts would be good, and the completely new diff, with the carbon fiber clutches should be pretty durable, and last me for quite a while, even with the heavy cargo loads.

Thoughts????

Anybody have a quick and easy way to make sure the housing/tubes itself is straight? I don't have to access to any fancy laser levels,etc... or even a smooth level floor. Just the dirt.

 

[Red FX4]

Reading about this reminded me of a problem I had with my 89 4WD Ranger with a LSD. I was getting a strange vibration from the rear that was worse under acceleration. I took it to a power-train specialist and they tool the differential completely apart but could not find anything wrong with it. They put it back together and the vibration was still there. I then took it to a Ford dealer and they agreed there was a vibration but could not figure out what it was. They put it on their dyno and could reproduce the problem but still could not pin point it. They were determined to find the problem and kept running it pretty hard on the dyno.


After a couple days I got a call from them and said they found the problem but it was going to be expensive to fix. It turned out the carrier had a crack in it and would flex under load and cause the vibration. The time on the dyno caused it to totally break and took the gears with it as well as the bearings. The Ford dealer wanted way to much to fix it so I paid the diagnostic charges and had it hauled to the power-train specialist for repair. They were so sorry that they missed the crack when they originally took it apart and gave me a good deal on the repair.

I find it hard to believe you could be having the same problem but stranger things happen.

 

[Carguy3J]

Interesting. That definitely doesn't sound like a common type of problem.
In any case, the plan I have (which I still haven't ordered any parts for yet) will replace the entire carrier anyway, so it will eliminate that possibility.

Does any body have any thoughts/opinions on my planned repair/upgrade detailed 2 posts up? Are the carbon fiber clutches a good idea on a heavy duty application (in comparison to the oem Mustang application)? Will I really see any strength increase from using a 31-spline carrier and custom 31-spline axles, while still retaining the 28-spline housing (and the smaller outer bearing diameter)?

 

[RangerX]

I would double check that you can put a 31 spine axle into your existing housing. I don't think you can, but I'm no expert. I swapped in a 1st gen Explorer axle, they have a fatter tube which I figured meant bigger bearings, etc.

I have one longshot thing to check that hasn't been mentioned yet. I recall a post or two from tears ago where someone's 8.8 had the spot weld that hold the axle tube to the diff break. Maybe check that?? Don't know if that could cause your symptoms, but...

Also, your truck as you described it, "1993 Ranger 4.0L-OHV, M5ROD 5Spd, 4x4 (1354 manual)
Regular cab, Long Bed,
2 piece rear driveshaft (w/ slip yoke, but no center bearing)
3.73 limited slip rear
265/75/15 " it identical to mine when it was stock! But I'm not sure what you mean about the driveshaft. Can you explain?

 

[RangerX]

Also, there's a good article on rebuilding a TracLok in the Tech Library over on the Ranger Station.

 

[Carguy3J]

I would double check that you can put a 31 spine axle into your existing housing. I don't think you can, but I'm no expert. I swapped in a 1st gen Explorer axle, they have a fatter tube which I figured meant bigger bearings, etc.

I have one longshot thing to check that hasn't been mentioned yet. I recall a post or two from tears ago where someone's 8.8 had the spot weld that hold the axle tube to the diff break. Maybe check that?? Don't know if that could cause your symptoms, but...

Also, your truck as you described it, "1993 Ranger 4.0L-OHV, M5ROD 5Spd, 4x4 (1354 manual)
Regular cab, Long Bed,
2 piece rear driveshaft (w/ slip yoke, but no center bearing)
3.73 limited slip rear
265/75/15 " it identical to mine when it was stock! But I'm not sure what you mean about the driveshaft. Can you explain?

Simple. It's a 2-piece shaft. There are two separate, unique major components or sections that comprise this shaft. The front slip yoke section, which is the part that contains the front u-joint, bolts to the back of the t-case, and has the "male" splines which allow it to mate with and "slip" in and out of the 2nd rear section (to allow a small change in driveshaft length as the rear suspension "cycles". The back "half" of the shaft is the "main" large diameter shaft.
Some Rangers have a longer, 3 piece assembly. I believe this would only be found on the extended cab, long bed trucks, as they would have the longest wheelbase. These 3-piece shafts have an additional "section", as well as a center support bearing; pretty much the same setup as is more common on full-size pickups, and large commercial vehicles. Essentially, with the longer wheelbase, it becomes necessary to support the shaft in the middle, in order to avoid a limp-noodle like effect. (Imagine a jump-rope in motion)

As for the axle shafts, no, the stock Explorer 31-spline shafts won't fit in my housing. They are slightly too long, and the outboard bearing surface diameter is larger. Moser ( http://www.moserengineering.com/axl...les/1993-97-ranger-2wd-and-4wd-spline-31.html ), and others I'm sure, make custom shafts that have 31-spline at the diff end, larger than stock, usually non-tapered, shafts of stronger material, and outboard ends which maintain the smaller 28-spline bearing surface diameter. Now, even the 28-spline bearing end is still a larger diameter than the rest of most 31-spline shafts, including the stock Explorer shafts, so that shouldn't effect strength, of the shaft anyway.

What I will be giving up is the increased tube diameter/strength of the Explorer housing, as well as perhaps the benefits, if any, of a slightly larger outer axle bearing. Although, the only difference is larger diameter, not width (I think), so the larger Explorer bearing size may actually me a slight negative; at least as far as high speed highway driving is concerned. The larger the diameter of a bearing the greater the frictional losses it imparts, which also generate heat. This is why NASCAR V8's typically use smaller "Honda" size main bearing journal sizes. Now, I realize in this application, its probably a completely negligible difference, but the theory is still sound.

 

[Carguy3J]

Also, there's a good article on rebuilding a TracLok in the Tech Library over on the Ranger Station.

I tried to "multi-quote" your 2 messages, to avoid having 2 separate replies, but it wouldn't work for some reason????

Yes, I've seen that, as well as several others. I'm sure I can do it, in terms of technical ability. I just really don't want to.

I haven't opened the diff yet, as I don't want to disable the truck until I have all the parts, nor do I want to waste about $70 worth of gear oil (Mobil 1 75w140 @ about $18/quart + tax). However, I'm assuming that the side/pinion gears probably have some wear on them as well, both from the age of the truck, as well as sustaining damage from prolonged driving with this problem. By the time I buy a complete clutch kit, plus the gears, plus a new cross shaft and bolt, it would be about $170, and I'm stuck with 28-spline axles. Also, it doesn't give me a new carrier.

For the $250 or so I mentioned in a previous post, I get a complete, assembled carrier, with all new gears, shaft, bolt, and upgraded carbon fiber clutches, as well as the upgrade to 31-spline. It just seems to make more sense to go that route.

 

[4x4junkie]

Does any body have any thoughts/opinions on my planned repair/upgrade detailed 2 posts up? Are the carbon fiber clutches a good idea on a heavy duty application (in comparison to the oem Mustang application)? Will I really see any strength increase from using a 31-spline carrier and custom 31-spline axles, while still retaining the 28-spline housing (and the smaller outer bearing diameter)?

You can put custom 31-spline shafts in your Ranger housing, however this does nothing at all to address any of your issues. You would gain no additional load carrying capacity (same-size wheel bearings), and no additional strength in the area of the wheel flange. The only things it would let you do is run bigger tires for serious offroad work, or to put some serious HP down at the drag strip, neither of which sounds like what you're doing.

An Explorer 8.8" in good shape is maybe $300 at a wrecking yard (less if you pull yer own). Putting a set of leaf perches and shock mounts on it can't possibly be more than a hundred bucks or so... If you can't swing that, I would just slam a new shaft into the existing axle and be done with it (check your gear oil, if it's still semi-clearish/honey-colored (no more than a hint of gray), chances are good everything's fine inside your diff).

Also, your driveshaft is typically referred to as "one-piece" (has one section). The Supercab shaft is a "two-piece" (two sections with the carrier bearing supporting it in the middle). If you really want to get literal about it, your driveshaft actually has 6 pieces: Slip-yoke, driveshaft, U-joint (2), axle flange, t-case flange.

 

[Carguy3J]

Well, I finally got the parts put in.
I did end up going with the new carrier ('03 Cobra, 31-spline, carbon fiber clutches) and Moser 31-spline axles.

The old l/s clutches were definitely worn, as were my side/"spider" gears. Comparing them side by side, it was quite obvious how much the gears were worn, compared to new.
Also, upon closer inspection, the axle shafts were also pretty heavily worn at the outer bearing/seal end. They were grooved and pitted. It was to the point that the seals, which were only a couple months old, were starting to leak.

The Moser axles are definitely "beefier" then the stock ones.

Everything pretty much just bolted right in. The only exceptions were needing a slightly thinner carrier shim on the left (perhaps a few hundreths, judging by the 'ole eyeball, comparing the stack to the old 1-piece cast iron spacer), as well as having to grind a bit off the end of the right side axle, so the cross shaft would clear.

I used Valvoline 75w140 full synthetic, with the l/s additive already in it. I did NOT add any more friction modifier. So far, there does not seem to be any need for it, as I have no "popping" or binding.

I made a brief drive right after finishing. It was about 15miles each way, back and forth to the store, up to about 55-60mph. So, no highway use yet. So far, it seems to have made a major improvement. The right is much better over bumps,etc.., with no more harsh banging. This was probably coming from the worn bearing surface/bearings, as I have seen a similar problem and fix from previous solid axle vehicles after replacing bad axle bearings.
There is now very little drivetrain "slop" and/or banging with on/off throttle application. This was most likely coming from a combination of the worn clutches, and mostly the worn "spider" gears. There is still a little bit of "slop", most likely coming from the t-case, but it's minimal and nothing to be concerned about. The axle shafts also now no longer have in/out play.

Handling seems to be improved as well, but something is still not right. I discovered a broken rear sway bar (the bar snapped, under the right side bushing- it appeared to be rotted), which I have not fixed yet, so that doesn't help. However, there stills seems to be a weird vibration. I haven't got it out on the highway yet, so I don;t know exactly how much of an improvement has been made.

I'm getting really frustrated with this thing. I have now spent another $600, without eliminating the problem. Like everything else I've fixed/replaced, the parts were bad, and it did make some improvement, but I still can't seem to find/fix the big issue!

 

[zhandax]

Here is another possibility I am exploring on my car; remove the caliper pins, shine them up, and replace them. I suspect the front calipers are more at fault for this than the rear. I saw this on a forum for my car in a post which sounds a lot like yours; the guy had replaced practically every suspension and drive-line part on the car and this was the only remaining possibility he could think of. Being short on time, I just bought rebuilt calipers for my car, but didn't get back from shopping for a Ranger today in time to install them.

 

[Carguy3J]

Well, just a little update on this. I believe I finally found the problem(s)

1.) and this is the "biggie", the right side radius arm bracket was moving. Several of the bolts had loosened up enough that the bracket could shift slightly. I hadn't found it before, because all the shops I took it to before insisted on lifting it by the radius arm brackets and front "eyes" of the rear leafs. I asked several times for them to lift if from the frame, so as to not "bind" up the suspension when checking for loose parts. Nobody listened, insisting it wasn't possible for the lift arms to reach the frame. Well, finally one shop did as I requested, and with everything hanging free, we were able to find the movement in the radius arm brackets. I tightened everything up, and put a couple of small tack welds on for good measure.

2.) I found that I had been running rear shocks that were too short, allowing only minimal extension travel. When I originally bought them (Gabriel "load assist" shocks), Autozone listed them for my 4x4 truck, as Gabriel still does on there website. However, when I recently went to replace them under warranty (they basically "projectile vomited" their fluid everywhere), Autozone no longer listed them. After a little digging, I found that they now only list them for 2wd Rangers. I then looked up Monroe "Load-Assist" shocks finding separate part#'s for 2wd and 4x4. Sure enough, the 2wd ones had an almost identical length and travel to the Gabriels. The 4x4 Monroes have about 2.5" more extension travel, and are longer overall. After installing them, I can feel a big difference. The rear end no longer "slams" over potholes. I suspect that the old too-short shocks were maxing out on extension and not allowing the opposite side to flex into potholes, with body lean, etc. I think it might also explain some of the strange rear tire wear. The rear tires had been getting "feathering" typically seen in front tires with camber and/or toe issues. I suspect that the vehicle was basically forced to roll the tires instead of using suspension movement.

I think I may also have the same issue in the front, but to a much lesser degree, with the shocks being a little too short, and limiting extension travel. I'll have to deal with that later though.

So far, it seems much better, and more "steady" on the highway. There is still some vibrations, but that may be due to the abnormal tire wear, and I may just have to live with that residual issue until its time for new tires.