1999 XLT - Rear Diff Rebuild Time

[kythri]

So, my rear diff has started making noise - kind of a rattling when coasting.

The noise goes away mostly under acceleration.

The diff has had a slow leak for a while, and the Explorer has been parked for some time.

Stupidly, I decided to take it out without checking the rear diff fluid level, and that's when the noise started.

Took it home, opened up the diff - it wasn't dry, but I don't think it even had a quart of fluid in it.

My ring and pinion look good, there's no metal bits/shavings/debris inside, so I sealed it back up, and put new fluid in.

No luck, noise is still there.

I suspect probably bad bearings, but ultimately, it's time for a rebuild.

The truck has 145K on it, so I'm going whole-hog on this.

Looking at an Eaton/Detroit TrueTrac as a replacement, rather than rebuilding the Trac Lok, and wondering what else I should do while I'm in there.

I figured rear wheel bearings since I'll have things apart. Master rebuild kit for the diff should cover all the bearings and seals.

Anything else?

It's got a Yukon 4.56 ring and pinion in there now. If it's damaged, and requires replacement, any recommendations over a Yukon?

 

[kythri]

Anyone?

Any specific reasons not to go with a TrueTrac as a replacement for the Trac Lok?

Any specific reasons not to go with Yukon gears?

 

[imp]

Anyone?

Any specific reasons not to go with a TrueTrac as a replacement for the Trac Lok?

Any specific reasons not to go with Yukon gears?

@kythri
I would ask how many miles has the 4.56 been driven? 4.56 gears are a bit rougher on things due to the extreme pinion speed. With 30" tires the pinion makes about 3100 revolutions per mile. Thus at 60mph, the pinion is spinning at 3100rpm. Your choice of rebuilding all bearings is a good one; the new True-Trac is an excellent choice, IMO. Just about the best for all-round work, but not as strong as a spool. (!). Trac Loks are so-so wear-out prone. Check the appearance and wear pattern especially of both pinion and ring gear. I would recommend especially a solid pinion bearing spacer instead of the usual crush-washer, and install it using someone (you) who understands it's theory and how to set it up. Too tight, bye-bye pinion bearings, too loose, anyone's guess. imp

 

[kythri]

If I had to guess, I'd say there's probably 20K-30K miles on it? The gears went in back in 2008 when it ceased to be the daily driver.

 

[SWIGIN]

If this is a play vehicle I'd just spool it and replace the bearings. A solid pinion spacer is not a bad idea as well.

 

[blakshukvw]

Solid pinion spacer for sure. All of the factory Ford bearings and seals and ring bolts are available on Amazon including the wheel bearings. Just rebuild your trac loc with the OEM carbon fiber clutch discs. It was good enough for 03 04 cobras and gt500. I know all of this because I just bought all of these items from amazon for my marauder. Even brand new ford gears. Those rebuild kits don’t come with OEM bearings. A lot of them have cheap bearings and seals and the shims are not oem quality either. OEM bearings are koyo.
I found new ford 4.10 gears including the pinion bearings and seal and ring gear bolts on amazon for less than $260. OEM ford gears are best and I don’t mean ford Motorsport. New trac locs with the carbon discs are available on amazon for $240 if you don’t want to rebuild yours or if the spiders gears are damaged.

 

[SWIGIN]

Solid pinion spacer for sure. All of the factory Ford bearings and seals and ring bolts are available on Amazon including the wheel bearings. Just rebuild your trac loc with the OEM carbon fiber clutch discs. It was good enough for 03 04 cobras and gt500. I know all of this because I just bought all of these items from amazon for my marauder. Even brand new ford gears. Those rebuild kits don’t come with OEM bearings. A lot of them have cheap bearings and seals and the shims are not oem quality either. OEM bearings are koyo.
I found new ford 4.10 gears including the pinion bearings and seal and ring gear bolts on amazon for less than $260. OEM ford gears are best and I don’t mean ford Motorsport. New trac locs with the carbon discs are available on amazon for $240 if you don’t want to rebuild yours or if the spiders gears are damaged.

03 04 Cobras and gt500 don't go off-roading often...lol

For a weekend warrior I'd agree but for an offroad only vehicle I say spool.

 

[imp]

03 04 Cobras and gt500 don't go off-roading often...lol

For a weekend warrior I'd agree but for an offroad only vehicle I say spool.

@SWIGIN

But do you get it there on a flat-bed (the 4X4 place) imp

 

[kythri]

My Eaton Truetrac showed up today, so goodbye Trac-Lok. It's not a dedicated off-road vehicle, it's going to see street use. A spool isn't an option.

I've got Timken bearings coming in for everything. In the event my ring/pinion is damaged, I have a new Yukon 4.56 ring and pinion - I've had Yukon gears in the thing for at least a decade, so figured I'd stay with that.

I'll likely rebuild the Trac-Lok and drop that into my Crown Victoria when I decide what gear ratio I'm going to go to in that (my current Vic, a 2011, has 2.73's in it - my old Vic, a 2002, had 3.27's - I'm thinking 3.55's or 3.73's).

What's the benefit of a solid pinion spacer? I've been Googling, and can't really find a good answer to that.

 

[gmanpaint]

Are you sure you want to go "All Out" on the rebuild? It can get a little crazy. I am sharing my 88 story after a simple $5 part broke.

What's the benefit of a solid pinion spacer? I've been Googling, and can't really find a good answer to that.

The Crush sleeve Eliminator setup uses stack on shims to set the pinion gear depth. You can remove the pinion nut, and reset it as often as you like, with the proper torque setting. If it comes loose, simply re-tighten. Can't do that with a crush sleeve.

In my case, my crush sleeve split, and backed off a bit, caused back n forth slack, destroying my good Richmond R&P 4:56 gears. When I rebuilt the entire axle, I used the eliminator kit. Look in the center of the crush sleeve for the split.

I went all out, and stripped the axle housing. Had the axle tubes welded to the center section. Installed a new Yukon 88 kit, with new Yukon 4:56 gears. Mobil1 synthetic 75-140, Re-usable Lube Locker gasket, 3/8" thick RuffStuff cover, Beefier Grade8 U-Bolts, POR15 paint treatment. New leaf springs and shocks, with U-bolt skid plates that raise the lower shock mount by 3". 1 month of work, and a drained bank account.

Stock U-bolts/mount on top, Upgraded bolts /skid plate mount on bottom.

And installed, ready to hit whatever.

Up to you how deep down the rabbit hole you want to go, but be warned, it's a deep hole. Bring a light.

 

[blakshukvw]

Kythri, I’ll have the complete 3.55 ring and pinion and diff for sale from my marauder in a few weeks after I install my new gears and trac loc.

 

[kythri]

gmanpaint: I figure I'm already half-way down that hole...

About a decade ago, I installed a Superlift K494 4" lift kit. Aftermarket shackles (I want to say these were made for me by Ruff Stuff Specialties, but I honestly don't remember at this point. They're not Warrior shackles - I have a set of Warrior 353's that I removed when I did the lift.

Anyhow, with the lift + other stuff, and some additional torsion twist, I'm sitting about 5" higher than stock. I'm pretty sure I replaced the U-bolts in the rear when I did the lift (I believe the lift kit came with burlier U-bolts/plates for the lift springs that were part of the kit).

I've had Ruff Stuff's diff cover installed on the rear (mine is tapped for a drain plug) since the lift a decade+ ago. Shocks are the Superlift Superride that came with the kit, though I will likely be looking for something different soon (though, replacement shocks are still available from Superlift).

I just ordered a Lubelocker gasket (thanks for that!).

I've got no issue going the rest of the way down the hole - I plan on an SAS someday. There's certainly cheaper 4WD/off-road type stuff I could do, but I like my Explorer. It's been with me quite a while.

blakshukvw: Thank you! I'll keep that in mind. I'll have the Trac-Lok from my Explorer soon enough, and I've got a 3.73 ring/pinion on the shelf already, so I might just go that route (not much of a difference between 3.55 and 3.73). PM me your asking price, if you don't mind.

 

[blakshukvw]

Oh yeah, go with the 3.73 you already have. That’s a better option. Plus you’ll need your 31 spline trac loc from the X that you already have anyway. I’m upgrading to 4.11 in marauder since the 4v has little torque to get it moving. 3.73 is a much better option for you. Btw, you can get OEM 4.10s like I did new or grab them used from a ranger or X.

 

[imp]

My Eaton Truetrac showed up today, so goodbye Trac-Lok. It's not a dedicated off-road vehicle, it's going to see street use. A spool isn't an option.

I've got Timken bearings coming in for everything. In the event my ring/pinion is damaged, I have a new Yukon 4.56 ring and pinion - I've had Yukon gears in the thing for at least a decade, so figured I'd stay with that.

I'll likely rebuild the Trac-Lok and drop that into my Crown Victoria when I decide what gear ratio I'm going to go to in that (my current Vic, a 2011, has 2.73's in it - my old Vic, a 2002, had 3.27's - I'm thinking 3.55's or 3.73's).

What's the benefit of a solid pinion spacer? I've been Googling, and can't really find a good answer to that.

@kythri
If you ask that, I suspect you may not understand fully the importance of the spacer, or maybe it's purpose. It establishes and maintains the pinion bearing preload, one of the most important parameters in the entire rear axle. The pinion bearings are highly stressed and turn very fast, 4.56 times as fast as the axles in your case.

The standard spacer is a bulged outward support placed between the two pinion bearings on the pinion shaft. As the nut is tightened the force applied squeezes the spacer causing the bulge to increase outward. This requires several thousand pounds of force, reached by tightening or torquing the big nut.

A solid spacer is more fool-proof and maintains it's squeeze on the bearings much more positively. It is much more difficult to set up. The high-performance cars from Ford such as the 427-equipped Galaxies all came from the factory with solid spacers. For normal use a standard spacer will suffice, but should never be re-used after tightening the nut once. Many will claim they reuse them and so have I, but believe me, unless you truly understand what's going on with pinion bearings, don't reuse one. I have seen gearsets destroyed many times by improperly installed pinion bearings. imp

 

[donalds]

I won't reuse them I did once not anymore and I fully understand how it works
thought I was gonna be slick
A few seals later new crush sleeve installed....May want to get 2 crush sleeve s for when you f up the first one...
It's good

It took a 3ft breaker bar and 200 foot pounds of torque just to start to crush the sleeve don't use a impact gun no matter what

 

[kythri]

I understand the principle behind the crush washer - just wasn't fully versed on why a solid spacer may be better.

Obviously, not going to re-use the crush washer - my rebuild kit came with a couple of them, so at a minimum, one of those will be used, but I've also sourced a Ratech 4105, so we'll see what ends up getting used.

 

[Mountinheer]

Just put eaton truetrac in w/ yukon 4.11 gears. I recommend a nice looking cover with fill port, and a gallon of redline 75-140NS.

Edit: B&M F-150 Cast Aluminum Differential Cover - 8.8 in. 40297 (97-14 F-150)

Or course, break in w/ cheaper dino oil like lucas hd, but I think the redline fluid mentioned above is the only synth without friction modifiers.

Edit#2: Red Line 57105 75W140NS GL-5 Gear Oil - 1 Gallon | eBay


OK, last edit: I used impact... just have to be careful because it takes a beating to start crushing, and then you have to creep up on it until it starts to get tight. Sounds very difficult w/ breaker bar, but maybe smarter?

 

[kythri]

Well, I ended up opting to have someone local do the work for me. The guy used to run a 4WD shop in the area, and has changed career fields, but was willing to do the work for me at an incredibly reasonable rate.

So, yesterday, my toy got the following:

New rear wheel bearings/seals (bearings are Timken-boxed, Koyo-branded made in the USA)
New rear diff rebuild kit (Yukon, Timken bearings)
New locker (Eaton Truetrac)
New ring & pinion (Yukon 4.56)
Lubelocker differential gasket
Ratech solid pinion spacer

I used Lucas 80W-90 gear oil, at the recommendation of Eaton's telephone technical support. Despite Eaton's printing of at least 3 or 4 different recommendations, including some which claimed synthetic was OK, or to defer to vehicle manufacturer spec (which would have been synthetic + friction modifier), this is what they recommended, not just for break-in, but for regular use.

The pinion bearing closest to the driveline (would this be the "rear" pinion bearing?) is sitting here in a baggie at my desk - I'll try to snap a picture of it later today and post. It is destroyed.

It screwed up the heat-treat of the previously installed Yukon pinion gear - turned the shaft blue where it met the (formet) bearing, and the hardening of said shaft is all screwed up.

That was the noise culprit. The other bearings obviously got replaced, but none of them were anywhere near as bad as this one. The ring/pinion gear teeth are perfectly fine, no wear (or no significant wear) on them from the past 10-11 years of running them. Of course, given the bunging of the pinion, they're not getting re-used.

All is (mostly) well in the world - now onto troubleshooting the newly discovered occasional failure of the fuel pump to prime/turn on when the key is on! Looking forward to what I figure will be a fuel pump replacement, woohoo!