rear differential carrier bearings

[Blakers]

Hmmmm. Thanks for the suggestion. This is a 3.73 rear end in a 2004.5 2500. What years of trucks would I be looking for to be compatible with mine?

Is an axle from a 3rd Gen 2500 gasoline-powered truck with the same ratio the same as one from a diesel?

 

[AH64ID]

Is an axle from a 3rd Gen 2500 gasoline-powered truck with the same ratio the same as one from a diesel?

Most likely not. Gas 2500’s were commonly fitted with the AAM 10.5” axle, and only the rare 03 SO/Cali Diesel had that axle.

 

[Blakers]

Most likely not. Gas 2500’s were commonly fitted with the AAM 10.5” axle, and only the rare 03 SO/Cali Diesel had that axle.

Thanks! I kinda remember that they had lighter axles.

 

[Richard05]

Update for those watching this saga. I have decided to replace the LS with an Eaton Trutrac. I have a preferred diff shop lined up but COVID has sidelined some of their workers so I have been waiting patiently for a good time to bring it in.

I am sure that they are well qualified to redo your axle. You have had foreign matter in every bearing set so far.
Make sure the housing gets flushed and brushed out or it's gonna happen no matter what you put in it.
Just my 2 bits.

 

[DonFitzwater]

What’s the difference between the AAM anti-spin and a Truetrac?

 

[Richard05]

What’s the difference between the AAM anti-spin and a Truetrac?

They are both helical gear type diffs, the eaton may be built a bit stronger which would be the reason most people would upgrade.
I am also interested to see how this works for you, mine has 320k on it and i'm sure i'll be in there soon enough

 

[AH64ID]

I think the Eaton also has slightly better biasing for slightly better operation.

No complaints about my AAM one, but if it failed a tru-trac would replace it.

 

[KParsons]

I think the Eaton also has slightly better biasing for slightly better operation.

No complaints about my AAM one, but if it failed a tru-trac would replace it.

 

[DonFitzwater]

I think the Eaton also has slightly better biasing for slightly better operation.

No complaints about my AAM one, but if it failed a tru-trac would replace it.

I’ve always disliked the AAM factory anti spin for poor performance. My 1995 Dana outperforms every new truck I’ve had in the lsd department. I will add this; I recently replaced the limited slip in my Jeep Liberty with a Tru-trac and it performs as well on ice and snow as the lsd and is smoother.

 

[Ozymandias]

I'd put a new set of gears and bearings in your axle. I've done that myself and these AAM axles are so Easy to setup compared to the Dana's, it was a breeze to do it.
I would only switch the axle if it is bent, but never for just a bearing/gear issue.

 

[Blakers]

I wish these axles were made like a Ford 9" with a removable center section. So easy to set up and you can rebuild a spare one to have on hand and switch it out in a couple hours. Lots of bigger truck rear ends are built that way.

 

[Ozymandias]

I wish these axles were made like a Ford 9" with a removable center section. So easy to set up and you can rebuild a spare one to have on hand and switch it out in a couple hours. Lots of bigger truck rear ends are built that way.

That's true, I'd like that too.

 

[sarj]

Update for those watching this saga. I have decided to replace the LS with an Eaton Trutrac. I have a preferred diff shop lined up but COVID has sidelined some of their workers so I have been waiting patiently for a good time to bring it in.

I'm curious what shop you're looking at. This is an interesting thread, & I have the same truck in the same place but with pretty low miles and I plan to keep it another 18 years even if I change it over to a work truck. I'm in CM.

 

[Superdawg]

I'm curious what shop you're looking at. This is an interesting thread, & I have the same truck in the same place but with pretty low miles and I plan to keep it another 18 years even if I change it over to a work truck. I'm in CM.

Sarj,
The shop is Unitrax Differentials, Drivelines and Overdrives in Anaheim. A friend of mine owns a general automotive shop and he sends most of his diff work there.

 

[Superdawg]

The shop called yesterday and they had opened up the rear diff. The bearings were damaged but the limited slip and the ring and pinion were fine. He was pretty adamant that synthetic oil should not be used in this type of diff. Limited slip additive is not needed but probably won't hurt. He thought the grinding/shuddering sound I had may have been from the limited slip and using the wrong oil.
I was torn about reusing the AAM ls but decided to have him put the AAM ls back in (extra grand for the tru trac) They cleaned it up, put an new bearing kit and 85/140 oil. They even painted the rear axle and diff cover w/ what appears to be undercoating?. Looks good and runs great. They want me to come back in 2500-5,000 miles so they can remove the cover, inspect everything and change the oil.
The real test will be to hook the trailer up and put some loaded weight on it to recreate the earlier scenario. Need to wait a bit for that.
Nice shop to work with.

 

[NIsaacs]

They cleaned it up, put an new bearing kit and 85/140 oil.

Nice, my kinda oil Interesting they didn't want synthetic....

 

[AH64ID]

The shop called yesterday and they had opened up the rear diff. The bearings were damaged but the limited slip and the ring and pinion were fine. He was pretty adamant that synthetic oil should not be used in this type of diff. Limited slip additive is not needed but probably won't hurt. He thought the grinding/shuddering sound I had may have been from the limited slip and using the wrong oil.
I was torn about reusing the AAM ls but decided to have him put the AAM ls back in (extra grand for the tru trac) They cleaned it up, put an new bearing kit and 85/140 oil. They even painted the rear axle and diff cover w/ what appears to be undercoating?. Looks good and runs great. They want me to come back in 2500-5,000 miles so they can remove the cover, inspect everything and change the oil.
The real test will be to hook the trailer up and put some loaded weight on it to recreate the earlier scenario. Need to wait a bit for that.
Nice shop to work with.

Glad you got it back, but there are some red flags in there.

Synthetic fluid is the factory fill, and is required by AAM for this axle. Not sure why they don’t want it, nor why it shouldn’t be in there.

85/140 is a very heavy oil for this axle too. In conversations with AAM they only recommended it above GCWR in Death Valley. It’s not that it won’t work, it’s not not needed or optimal especially if it’s not synthetic. Even on 2021’s with the 11.5 the recommendation is 75w-85 synthetic.

Painting the diff cover with undercoating will have a negative impact on cooling.

Might be worth a conversation when you go back in.

 

[Superdawg]

Oh fun. I just returned from a long driving trip taking care of some family medical issues and was not thinking Dodge specs.

I remember now AA specs synthetic. It is interesting though that the Eaton trutrac appears to be a similar unit in function and they spec non-synthetic. I will give the shop a call and discuss this when things settle down here.

I just took a closer look at the rear axle. It is black paint, not undercoating. It's my axle that has the texture on the exterior.

 

[Superdawg]

On second thought I remember a post by Cerb and he described the AA LS as having small composite shoes. So maybe different than the all metal Trutrac.

I'm not too concerned about the 85/140.

 

[AH64ID]

The AAM unit does have 3 small friction “tabs”.