Pinion Shaft Operation!?

[ProjectSoloGear]

My brother has a 98 Explorer XLT 4.0 SOHC RWD and recently developed the whinny noise coming from underneath the car (68k miles). When we brought it to the Ford Dealership they said every bearing in the rear axle and in the differential housing needs to be replaced along with the seals. The quote was around $1600. Since I'm mechanically inclided, have a mech engineering background, and the explorer didn't need to be used right now, I decided to give it a shot myself and made this into a project.

I did a lot of research on this website and signed up as a member a few days ago. Got the Chilton manual from the library and took a look at the rear axle. I jacked up the car, supported it on stands, checked the fill plug and the housing was full (no leakage), checked all the seals and every seal looks undamaged, and opened the differential housing cover. Found no obvious metal debries inside the housing or in the oil. Gears looked unharmed, and as far as I can tell everything looks good inside. Pulled the two axles out of the side, checked the wheel bearing, it rotated fine with no restriction--no debries there also. That leaves me with the differential assembly, ring and pinion, and the remaining hidden bearings.

I got this far and realized the Chilton manual doesn't go further. I think I'm going to ask you guys for assistance from here. I read the articles on the rangerstation.com tech section and realize the pinion backlash setup and the torquing on the nut is a pain in the butt, and without further instruction by the Hanes manual, I'm stepping into danger zone.

I asked a mechanics friend, he was suppose to come visit tonight and check it out but was held up, and over the phone he says it could either be the pinion bearings or the shims being worn too thin. Does anyone have any comment. Should I be checking anything else before I dig into the pinion and ring? Where can I find information for special tools needed, detailed instructions for removal and install? I don't even know how much torque is needed to put the two carrier bearings back on. Most likely I'm going to pull the pinion shaft and have NAPA replace the damaged bearings (if that's the case)...but nightmare awaits me when I return to put everything back in. Any help is appreciated.

Regards,
Dominic

 

[Robb]

Setting up R&Ps can be done by shadetree mechanics with the proper tools and research, BUT it is highly NOT recommended. It is a very low tolerence operation, and one that should be left to the pros.

$1600 is just friggin outrageous!!!!!!!!!!!!!!!!!!!!!!!!!!

My pinion bearing (at least) went bad in my '95 at just about the same mileage. I had the rear rebuilt for about $500, which in hindsight with the same r&p, was too much. I have found places since that will do it for less, and would probably do a better job (it only lasted 18K miles).

You have a few choices here. 1) take a chance doing it yourself (a Google search would probably lead to rebuild procedures) 2) find another X 8.8 used or sitting in a junkyard and just swap it in 3) find a reputable shop to rebuild it for MUCH less than $1600 (you could also swap gear ratios at this point for a more desirable one if you so desire)

 

[ProjectSoloGear]

thanks for the reply Robb

I was thinking of the same thing too about picking up a rear end at a junk yard. The only problem is, there's no guarentee that that rear end would be in good condition. After reading around the forum, it seems like this problem happen often to people.

I asked around tranny shops around here, they're charging me upwards of 600 bucks to remove and install a whole new pinion assembly. Where can I find a 4x4 shop that specialize in this so they don't charge the "commercial" price? I'm in southern CA, Los Angeles.

So anybody else have the torque spec for the carrier bearings or a more detailed description of how to setup pinion backlash and depth? Any help is appreciated. Thanks.

Dom

 

[Robb]

Alright, I could have given you this the first time, but I thought I would warn you first.

 

[Doug]

After contemplating doing my own gears for the past year or so, you can replace the pinion bearing your self bit it isnt something you not willing to try hard at. You have to realize your dealing with measurements in the thousands (.001) of inches. if it's off by just a little bit you're gonna eat up your gears. Though since you're doing bearings you shouldnt have to set pinion depth of preload you can reuse the existing shims. The one thing you are going to have to do is set the pinion bearing preload and for this you need an inch pound torque wrench. It's not going to be that hard of a job if you're good with tools and have a head. I dont beleive the pinion bearings are pressed on so it should make it that much easier for you.

 

[Jefe]

If you decide to take it to a shop I can highly recommend Ramjet Rear End Repair in Sun Valley. They'll probably charge $150 labor + parts.

 

[ProjectSoloGear]

deleted *double post error*

 

[ProjectSoloGear]

Robb: Thanks for the link. I read through that about 3 times now. It looked confusing at first but after a while it made some sense. The three sections in the instructions that do still confuse me are 1) Pinion depth set-up 2) Pinion gear mock-up and 3)And now for a little assembly.

Doug: In the link Robb provided, the pinion depth set-up must be done prior to disassembling the pinion and shaft. Since I'm not replacing the diff or the gears, can you explain in more detail why I don't need to worry about the pinion depth? If I'm not setting up the pinion depth, does that mean I don't need to worry about the differential backlash and run-out? I'm assuming since I'm using the original shims, the depth should already be set to factory standard. If I go ahead and check the backlash and run-out and find out I needed to make adjustments, I assume that means I'll need to adjust the shims regardless if it's the original one, right? I got a better idea. Why don't I check the backlas and run-out prior to disassembly and see if it needs adjustment. If it doesn't, that means the shims should do fine. Where can I find gear marking compound? Who makes them?

Jefe: I'll give the shop a call today. I'm not sure if any shop is opened on Sundays, but I'll find out soon. Thanks for the info, they're less than an hour away (without traffic!).

Some questions I have about the instructions. In the Pinion Gear Mock-up section, the instruction says:
"Tighten the nut until you achieve the proper bearing pre-load torque (16-29 in-lbs new, 8-14 in-lbs old: Note: this is not the torque on the nut. It is the torque reading generated while rotating the flange/pinion assembly.)"
It sounds kind of vague to me but I've to ask one of these stupid questions: if it's not the torque on the nut, where do I make the measurement and with what tool? Another stupid question, the crush sleeve needs to be crushed with min of 140 ft-lbs of torque. When I rotate to tighten the pinion nut, wouldn't the whole pinion assembly rotate also? How do I tighten something that rotates on roller bearing?

Thanks for your input guys. Keep it coming. I hope this is helping others who are in the same boat.

Dominic

 

[Doug]

Personally I wouldn't go tinkering with the backlash and pinion depth. The shims are what set the pinion depth and backlash and since you're not changing gears but keeping the same ones you're not going to have to mess with backlash, pinion depth or run out. The only issue you're going to have to worry about is the pinion bearing preload. You're going to need an inch lbs torque wrench to set it.

 

[Eneurb]

If you are only changing the bearings, you don't have to set pinion depth or backlash providing that you put the pinion shim back in, and don't mix up the side bearing shims. A little tip to make the job alot easier, if you are using a new colapsable spacer, give it just a slight crush in a vice before installing it. That will make it alot easier to install the pinion nut.

 

[ProjectSoloGear]

Updates and some questions

Hey guys,

I've accomplished alot in the past couple days so I'm giving those interested a little update. I finally took everything apart in the rear end. Since last, I've removed the carrier bearings, its appropriate shims, the differential assembly, and removed the pinion shaft assembly, flange, the pinion seal, and removed the front bearing. Finally, I've discovered the problem! The front pinion roller tapered bearing assembly bearings, upon inspection, had marks, scratches, and spalling all over the place. They were deep enough to be felt by my nails but not by the touch of the finger. The rear pinion bearing that is pressed onto the pinion shaft showed very little signs of damage, though I do see minor scratch marks. Since I'm already pretty deep in the process, I might as well replace anything that could go wrong in the future. Thus, I'm planning on replacing both the front and the rear bearing assembly. I checked and double checked all other bearings (2 on the diff and 2 wheel bearings), they all look perfectly normal. Seems like not enough metal debris snuck into the diff housing and into the axle tubes to cause any damage. Off to Ford I go tomorrow morning.

Now comes the question(s)
1) I was inspecting the pinion gear itself and realized something worth noting. There are two planes on the pinion gear that is vertical in its installed position. The plane that is closer to the front of the vehicle is what I'm addressing. The edges that intersects the flat plane and the pinion gear teeth seems non-uniform to me. The edges of individual tooth aren't straight lines, instead they look a little "zig-ziaggy/chipped" to me. It is not apparent through out the rest of the pinion gear, but it is on the edges I'm describing. Is that normal?
2) The bearing cup (outer race) of the front pinion bearing assembly has very minor spalling marks. I counted a total of about 4 locations, each marked in the measurement of millimeters. I don't have a race puller or a press, is it of paramount importance that I replace this race/cup?

That's all for now. More updates tomorrow. Perhaps I can take it out for a spin, wash and wax, and enjoy the "better" california weather. Please help if you know some answers.

Dominic

 

[Doug]

Personally I'd replace the races you should only need a 2 jawed puller I beleive, maybe a cold chisel. I'm not quite sure what you're talking about as far as the gears It sounds like you're talking about the wear pattern on the drive side of the gears. There really shouldnt be any where on the gears but it's kinda hard to know whats going on with seeing pics.

 

[ProjectSoloGear]

Project Success!

I'm finally done with the repair. Took the Explorer out for a drive and tried my hardest to listen to any sounds. I heard none. What the dealers quotes as a $1600 parts and labor turned out to be a fix for $129.25. Pretty cool huh?

Couple of advice/info for people who are doing simlular things.
1) when you purchase parts, make sure you get "two" crush spacers.
2) The crush spacers are HELL to do. I know every single instruction warned that it's the most difficult part; You better believe it! The manual quote "it requires a minimum of 140ft-lbs of torque to crush the spacer." I used my torque wrench and measured a minimum of 224ft-lbs of torque to crush it. Without a lift, it was completely hell to do.
3) The pinion pre-load is measured in in-lbs. I mistakenly read it as ft-lbs so I ended up tightening the pre-load 12 times more than it needed. If you find yourself in the simular situation, you should be glad you bought "two" crush spacers cuz you won't have to make an extra trip down to ford especially in your frustrated mood. They're something like $5 or less each.
4) As you're tightening the pinion nut, take your time. When the pinion assembly feels like it's getting tight against the pinion nut, wiggle it back and forth often to feel for play. When the play is very little (millimeters of movement), this is when you need monster power to start crushing the sleeve. At one time I lifted the rear end of the car with the torque wrench (the rear axle lifted off the jacks...dangerous!). At this point, tighten a little (3degress) at a time, and check your pre-load. I don't know how sensitive it is to get the pre-load exactly on the mark, but since every manual and instruction warned in BOLD letters not to exceed the pre-load, I guess I would suggest the same.
5) Make sure you have a in-lb wrench that can read as low as 9in-lbs. I had to drive out to sears in the middle of trying to finish setting the pre-load.
6) The instruction for the 8.8 axle in therangerstation.com site suggested 2 quarts of gear oil. My explorer needed around 2.6 quarts. I filled it up to 2 quarts before I took it out for a ride, but after driving around, I had to refill it to 2.6 quarts. I figure the reason for that is I cleaned out the whole rear end including the axle cylinders and the whole diff housing, so the oil needed time to settle down. Also, the car may be tilted up a little? There was enough space underneath the car to fill the axle without jacking up the car.
7) To remove the filler plug, I used a 3/8" drive extension with a socket wrench.

I can't think of anything else right now, but if you need more help in anyway, feel free to e-mail me at Projectsologear@gmail.com

Good luck and thanks you for all the support. Explorerforum you rock!

Dominic

 

[Eneurb]

I have no idea what your dealer was quoting you for $1600... I work for a dealer, and doing bearings only on an 8.8 costs about $700 canadian... they must have been quoting you a new gear set.

 

[Glacier991]

Dominic.... thanks for your posts here. They will be very helpful for others. I ALMOST mentioned that poeple OFTEN mistake FT LBS for IN lbs. Generally when I see someone mention IN LBS I point that out. I might have saved you $5 and a trip had I done that here. DId you take pictures of this process ?

 

[section525]

Yes, pictures would be sweeet. I am a rear-end retard.. so are you saying during this process you could have changed your (his) gear ratio as well?

While doing my cam swap, I mistook 17 FT LBS with 71 FT LBS. Ooops.

 

[ExplorerSportNu]

Yes, pictures would be sweeet. I am a rear-end retard.. so are you saying during this process you could have changed your (his) gear ratio as well?

Yes I 2nd this, changing the gear ratio part while doing this same process ?

 

[ProjectSoloGear]

Thanks for the replies guys,

I must appologize I did not take any pictures. However, if you use the 8.8 tech article in therangerstation.com, you'll find more information than you need. Also, if you go to the Ford dealership, they can print out an exploded view of the rear end, it helped me a lot. It is essentially the same picture that can also be found in the rear axle diagram in therangerstation.com.

section525: lol, hope no damage was done.

ExplorerSportNu: I suppose I coulda changed the gears, threw in a different differential or put a lock-chuck in there. I figure since I was a "rear-end virgin," I best fix the problem first before going out and modding the Explorer. Also, I don't want my bro to have too much fun, it's his car afterall!

Dominic

 

[cdsl227]

Thanks for the replies guys,

I must appologize I did not take any pictures. However, if you use the 8.8 tech article in therangerstation.com, you'll find more information than you need. Also, if you go to the Ford dealership, they can print out an exploded view of the rear end, it helped me a lot. It is essentially the same picture that can also be found in the rear axle diagram in therangerstation.com.

section525: lol, hope no damage was done.

ExplorerSportNu: I suppose I coulda changed the gears, threw in a different differential or put a lock-chuck in there. I figure since I was a "rear-end virgin," I best fix the problem first before going out and modding the Explorer. Also, I don't want my bro to have too much fun, it's his car afterall!

Dominic

Since no pics were taken... and it just so happens that I paid to have my 4.56s installed and they screwed it up and I tore 3 teeth off the pinion...and since I'm currently in the process of doing my gears myself (so it's done right this time)- I'll take some pics and post them in my SAS project thread.

That was a good move getting extra crush sleeves, I got 2 extras on top of the one that comes with the master rebuild set. I got my axle all cleaned out- all the pretty metal flakes. I'm waiting for the pinion depth tool then I'm off to the races.

You getting yours together is an inspiration.

I'm just hoping my ARB is ok, I'm going to clean it up as best I can, since i didn't go far after breaking the pinion teeth I'm thinking I can clean it up.

For those asking- when you change ring and pinion they have to be done in matched sets because they're "lapped" together as a set, you're not suppose to mix pinions and rings from different sets even if they're the same gear ratio, but I'm sure somebody somewhere has done it.