I was driving on the highway recently, when my truck suddenly had a loud grinding sound. A mechanic took a look at it and says that my rear differential is shot, and that I need to replace my rear end.

He quoted $3300 to rebuild it in-shop, or $4100 to buy it rebuilt. Both of those prices are quite a bit more than I want to put into the truck. That said, I looked at salvage yards around here, and found a couple rear axles in "A" condition (with roughly 100K miles on them) for around $650.

I'm leaning towards getting the axle and replacing it myself, but I've never done any work with on the rear-end of cars, so I don't know much about them. So I have a couple quick questions:

1) "Rear-End" and "Differential" seem to be thrown around pretty equally - are they the same thing, or does the rear-end include the differential plus other parts?

2) It seems like overkill to replace the entire rear axle if only the rear end needs to be replaced. But I can't find just the rear-end for sale on the salvage yard search engines. I assume that they generally only sell the entire rear axle, but want verification that replacing the entire rear axle should include the differential, and should resolve my issue. (I can't imagine it wouldn't, but I've made dumber assumptions before...)

3) It shouldn't be too difficult to replace the rear axle, should it? Since my truck is in the shop, I can't look at it for verification, but it should be as straightforward as jacking it up, removing the driveshaft, and detaching it from the suspension. Is there anything I'm missing?

There obviously wouldn't be a warranty with the salvage-yard axles, but given the difference in price, this seems to be my best option - anything I'm not considering?

Thanks,
~Dean

 

One more question I just thought of:

When I jack up the truck, I usually put the jack under the axle. If I'm replacing the axle, I won't be able to put the jack under the axle or suspension. I could try the frame itself, but I don't think there's an area where the frame is close enough to the ground for my jack to reach it. How else should I jack up the rear end in a way that won't bring it crashing down on me? I have jack-stands, but again, (without the truck handy to look under) I'm not sure where I can put them that would hold the truck up high enough...

 

That is WAY to much money for a rebuild, or, a rebuilt unit. You can get custom rear axles made for less than that. Simply swapping them out should be less than two hours labor, if you have air tools..... If you don't, I hope your upper body is in REALLY good condition. Its a workout.

Buying the whole rear axle from a yard isn't a bad plan. Just do basic maintenance before you install it, fluid change, and brakes, and you should be golden. Just make sure it has the same gear ratio that you currently have.

Terminology here is mutable. Different folks will call parts, or even the whole thing, by different names. Not really unusual. Generally though, "differential" is the whole thing.

As for jacking it up........ you are going to have to support the truck on the frame. If you don't have a lift to use, that can be quite fun. Do NOT use cinder blocks. Bad things happen with those...... I used a forklift once...... that was fun...... I have the luck of having a shop available to me for use for that kind of exercise now though.... Got any friends that do the wrench turnin' thing for a living? Might be able to have the help ya out after hours, or some such.

 

WOW....rear end rebuild should be 800-1000 dollars parts and labor, that guy is trying to rip you off!

 

Thanks for the response!

With respect to fluid, am I going to need to drain all the transmisison fluid, or will only a small portion come through the differential?

I hadn't thought about the brakes - I've replaced the disc brakes on the front before, but never drum brakes on the rear. Do I need specialized tools for drum brakes?

Thanks again!

 

Yeah, that was my initial feeling too. Gotta love people that will take advantage of situations like that...

 

No tranny fluid in the differential guy. Diffs use gear oil (80-90w if i remember right). A small amount of tranny fluid may come out of the tail housing when you remove the driveshaft, but really not enough to worry about (just top it off when you're done).

Drum brakes are a bitch in my opinion. It looks like someone had a good, working idea for brakes, and had about 500 springs lying around, then decided it would be a good idea to throw said springs in there for no reason. (but no, you wont have to have anything special for them-except maybe a little spring compressor screw driver thing I forget the proper name for)

The terms rear end and differential are pretty much interchangeable. Both can mean the entire rear axle, or pertain to a more specific part (such as the carrier) it all depends on the context.

As for the whole install, pretty straightforward and easy, but as stated above you will get a workout... definitely a 12-pack job with some friends

 

Another option I have is a friend of a friend that's rebuilt differentials before. He says if I provide the parts, he'll rebuild the differential for $375. Depending on the cost of the parts, this is a pretty appealing option, since I'd have a differential with new parts in it, vs a used differential from a salvage yard.

But I don't know enough about differentials to know what parts to order piece-meal. So I've been looking for rebuild kits for a 2001 Dodge differential, but I'm not finding much. I can find kits like the ones advertised here, but they don't seem to have the kit to match my truck.

(I've also found bearing and seal kits, but I don't know if that's all the parts I'd need for a full differential rebuild, or if I'd need other parts as well.)

Any suggestions as to where to look for rebuild kits for a 2001 Ram? Also, does it matter that it's a 4x4?

While I'm at it, if I decided to go this route, would it make sense to change the gear ratio to get better mileage?

Thanks for your continued help,
~Dean

 

Sorry to keep bombarding the forum with questions, but I've found a Timken Differential Rebuild Kit that looks like it'd do the trick. But I thought I'd run it by you guys first - is this what I'm looking for? Am I likely to need anything else?

Thanks,
~Dean

 

What parts you need depend on what happened to yours.... Picking one up in the yard still might be less expensive....