Eaton rear end questions

[mikep]

This Morning I tore into that pile of Eaton stuff I got yesterday and I have a couple of questions...

First off I have to say I wish I had known about eatons earlier. I didn't realize how heavy duty and easy to work on they are. Theyr'e like a 9 inch Ford on steroids . The detroit locker unit I got is in Perfect condition. I'm stoked although someone could have warned me to bolt the thing together before I broke open the differential! It took 10 minutes to find one of the springs.

Question #1 .. I think I have the whole bearing adjuster thing down for backlash setting but whats up with the brass faced adjuster located at the front of the differential near the face of the pinion? I assume thats not actually supposed to ride on the back of the ring gear all the time . Whats the reccomended adjustment procedure on it?

Question #2 What are the torque specs on the ring gear ? I cant find them anywhere?

Question #3 Anyone make a chrome cover?

Question #4 I hear some 14 bolt parts will work in these. How about R&P gears? I might set one of these carriers up with hiway gears.

[mikep]

Nobody knows Eatons?

[crazy longhorn]

Ring gear thrust pad adjust......after the carrier is assembled ,& adjusted, install the thrust pad & tighten the screw untill the bronze tip engages the back of the ring gear, while the ring gear is rotated. Then back off the screw 1/12 turn, & tighten the locknut. From Motor truck & deisel repair manual. Sorry, I couldnt find the tork specs on the ring gear. Good luck,crazyL

[mikep]

Thanks. In going though these today I was left wondering what the downside to the Eatons is? I couldnt see it. Do they break ? Just heavy ? Why the lack of reference and parts availability. I see an awful lot of them around. Theyre easy to work on. The drop out design seems well suited to off roading and the like. I'm digging have 3 seperate pumpkins ready to go.

[Dean]

I've been into a lot of these Eatons and they are one heavy duty rear end. I'd recommend looking at a factory shop manual for most of your questions. It has information about the locker also. I have lockers in all of my K20s. I can copy the manual if you need it. I have the pinion seal part number also if you need it. There is a setting procedure for that pinion snubber also. I don't think you will break one of these rearend.

Most of the complaints I see on here are about parts availability. I've never had a problem with that. You can not buy the Detroit Locker new anymore, but you can find used ones.

[mikep]

Thanks a lot. If you could copy that manual for me I would be in your debt!

[neonlarry]

The only bad things I have ever heard about eatons is they are hard to find parts for, and it is hard to get the brake drums off, but I never looked to see if that was true.

[mikep]

Thats the good thing about having a pile of pumpkins. One can break and ...who cares ... besides theyr'e all over the junkyard.

[67cst]

Im and eaton, what do you want to know? lol

[COBALT]

I didn't rebuild mine myself, but I had Randy's Ring & Pinion do it for me after I first got the truck.

They're tougher than nails, but when they bust they bust hard. It cost a huge pile of $$$ to get mine running again.

I have an HO72/52 coil spuring 8 lug 10 bolt corporate axle. The original 4.10 gears I still have, but I had them change out to 3.90. Spiders aren't made new any more so you have to buy used. There also aren't any posi units to put in the carrier unless you're lucky to get your hands on an old one from way back. The only new gear set you can find will be 3.90s. Used there's everything from 3.90 all the way up to 4.56 I think. There were a few 3.73s floating around but they're extremely rare and probably not in good shape.

Detroit lockers you can buy new, because I bought one through Randy's for my axle. It was the only alternative to used spiders. They're expensive, though, and so are the carrier bearing set. Labor was cheap compared to the parts.

Nix on the chrome cover. I spent a good few months looking around for gaskets, chrome covers, and other accessories only to come up dry. That doesn't mean they don't exist, but I finally decided to not bother. You could have an old one chromed I guess...

[mikep]

The ratios's go a little farther than that. I got a 5.14 , a 4.57 and a 4.11 in this lot of stuff I bought saturday. I think randys might have taken you for a little ride there. I just checked the carriers bearings and they are the same as Dana 60 bearings . Just wondering. Why did you decide to go with rebuilding yours instead of buying a good used one? It seems like it would be fairly expensive to have done. I dont know what randys charges but I have heard they are high. Those things are all over the junkyard for a hundred a carrier or so. Theyre extremely simple to set up and adjust compared to a lot of rear ends.

[COBALT]

I was pretty new to these trucks then. I needed it drivable and couldn't spend the time/energy to do all of the searching around or working on it myself. I als didn't have very good tools to do any precision work.

My HO72/52 had a seized spider that heated up and welded itself to the carrier cross-member. I remember looking at that carrier wondering how in the hell it managed to turn the driving axle. Every bearing in the carrier including the pinion bearing were literally destroying themselves, but the carrier and the gear set still were in good shape with a good wear pattern....wierd. The axles were in good shape too.

I double-checked their prices after I had the work done. They didn't over-charge me even though it seemed like it at the time. The carrier bearing set was a couple hundred $ for everything. From what I understand they are not the same as the Dana 60, at least they didn't seem that way to me. They didn't look interchangeable. The detroit locker was $550 new. I could have bought used, and that is retail for that unit, but I wanted it fixed quick. The carrier and gear set were still in good shape so I kept those (they're still sitting on my shelf), but I elected to go with a new gear set, which ran about $250. I didn't have to, but I wanted a lower gear ratio. Labor was only a couple hundred $ for everything, and it was done right with no problems and a pretty good warrantee I knew they'd honor. I had a couple of issues with the locker and they inspected it after 500 and 1000 miles for free with no problems.

...now I wouldn't elect to do the same thing now that I know what I know, and have the tools and the time, but then it was sort of a no-win situation. You might remember, but back then I got on this board and begged and pleaded for help with not much feedback, so I considered myself sort of the crash-test dummy for corporate axles. I also had no contacts or knew anyone who could teach me or help me out, so I elected to go the expensive route.

Good news is I have a SUPER strong axle that doesn't leak and takes all the abuse I can throw at it, and I'll be able to sell it for good $ when I decide to swap it out (I already have a buyer), so I don't consider it a huge loss.

I figured the gear ratios went higher (lower) than 4.56, but I didn't remember the values.

Good luck.

[Don Smith]

This web site has good info on setting up posi. Ring gear bolt torque 90 lbs. www.gnttype.org/techarea/suspension/posi.html

[Vince M]

A couple of notes from my experience.

The spiders are not available new.
The axles are only 17 spline (or there abouts). Never found a source for new ones just used.
The bolts that hold the cover and third member go through the case so they need to be sealed with some kind of sealant. Also the axle retaining bolts. I think I used Permatex on mine.


In mine the axles were worn along with the spiders and I got one helluv a clunk when I put the truck in gear and then again into reverse. I couldn't find any new parts and I found a good 14 bolt for $100 with a 3.73 ratio so I just swapped it out. The ring and pinion on mine were like new. Just wish the rest of it was. I really liked the round pumpkin and painted my cover gloss black. Never saw a chrome one in my searches. Never saw or heard of a 3.73 for this rearend either.
I think the hubs are the same as a Dana 60.

[COBALT]

I've had a few people try to clobber me about the whole 3.73 thing. I saw exactly one set once and only once. Either this was something a dealership agreed to swap, or these were aftermarket some time in the '70s or '80s that aren't made any more. Needless to say it wouldn't make much sense to buy a 3/4 ton truck that can't tow as well, but I've heard of truck owners deciding to reduce their ratio after they've bought the truck because they realized they weren't going to tow as much as they thought, and want to drive down the freeway faster than 60 mph...

I saw them when I was pretty new to these trucks. If I'd seen it later on I would have gotten a part number or something, but....live and learn.

[mikep]

For anyone wondering what a detroit locker eaton differential looks like ...this is it.

[Vince M]

Cobalt..thanks for the info on the gear ratio's. I'll tuck that away in my memory banks. I always wondered why nobody made a lower numerical ratio. I always figured it was due to pinion diameter or something similar.
I like the 3.73 I've got now...seems to be a good compromise for city and highway. Someday I'll put in that 700r4 I've been wanting and have the best of both worlds.