Can a differential carrier go bad? (1 Viewer)

Joined
Mar 22, 2005
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136
 
 
 
Need advice. 1987 FJ60 with semi-float rear end. Replacing all the rear end bearings (wheel and differential). Machine shop is doing the differential work for me (press bearings on/off and preload, etc). Machine shop tech says that the differential carrier (that the ring gear bolts to, which the FSM labels as the differential case) spins, and that I need a new one. Does this sound right and is it possible? After 248K miles anything could happen, but this is something I don't read about. I don't have any differential repair knowledge and need to know if this is the way they are made and/or if he could be right. I just don't know how many FJ60 parts he sees, but he is very experienced and I feel that I should trust him unless I have a good reason. (He also did my 2F head work and did a good job.) What you say?
 
Joined
Oct 31, 2003
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5,009
Location
Meridian,TEXAS
 
 
 
The only areas of concern are wear points where the axle side gears and spider gears contact the carrier and fitment of the spider gear shaft......

Whats he worried about??
 
Joined
Mar 22, 2005
Messages
136
 
 
 
Just got the call today after hours, so haven't been over to see the issue...but, he says that it spins freely and said something about the spiders. It all looked solid to me, and I don't see how this part could possibly go bad. But he did clarify by saying after looking at my FSM copies that it was the differential case - as labeled by the FSM, however, it is commonly known as the differential carrier - and then specified that it was the part that the ring gear was bolted to. I thought this was a solid machined piece, but I did not take it apart...
 

Wile E Coyote

Out in the streets, they call it murder!
Joined
Sep 20, 2005
Messages
3,197
Location
Western AZ
 
 
 
"Can a diff carrier go bad?" in a word--yes. Doesn't happen in a daily driver but very rarely, and on a typical trail truck only slightly more often. They crack from stress, or hog out where the pinion shaft runs through. Again, very rare but for a fringe bunch of wheelers running big rubber, lunchbox lockers with stout axleshafts, for one common scenario.
Not sure what he might mean by 'spins' though?


Edit: Grant beat me to it. I type/think darn slowly sometimes, hehe.
 

ntsqd

technerd
Joined
Apr 26, 2007
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5,986
Location
Upper So. CA
 
 
Yeah, spins where?

The only scenario I'm coming up with is that the case/carrier side bearing spins on the spigot of the differential case/carrier and is not a press fit.

The 'gitcha by' is Lock-tite Stud & Bearing mount, but the proper fix for that is a new case/carrier.
 
Joined
Mar 22, 2005
Messages
136
 
 
 
Correct and quick work team!

Went to the machine shop to observe. Sure enough, the bearing was not solid on either end of the carrier...and he said should be a .004" press fit. He was not equipped to re-sleeve or otherwise repair the carrier. He said that this is not common but can happen...something about being hot and seizing and then turning. Anyway, new carrier on the way...and requires different/new bearings...which I also ordered and will return the new ones for the current/bad carrier. FYI

Thx for the good response and discussion, I was better informed!
 
Joined
Mar 22, 2005
Messages
136
 
 
 
the deed is done!

orange, good question - new carrier was $300 new from toyota. my machinist took the new parts and did a wonderful job. all assembled now and i am rolling! so, a recap of what happened...

very noisy rear-end, sounded like brakes or perhaps even transfer case, sometimes metal-on-metal sounds...using a tube, noise determined to come from rear pumpkin. ordered all new bearings for entire rear axle and diff. pulled diff and took to my local shop which pressed all bearings and did diff setup for $150. i replaced axle bearings and seals. very careful to keep everything very clean; care with new gaskets and seals. painted rear diff cover to prevent rusting. fill with new gear oil.

result - as quiet as a magic carpet!

(NOTE: the gears were fine and did not require replacement.)
 

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