Front Diff Failure (1 Viewer)

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C

Chompers

Joined
Aug 10, 2016
Threads
4
Messages
180
Location
Rio Rancho, NM
Hey Peoples! My last wheeling excursion, I heard and felt popping in the 3rd Gen 4Runners front drive train. Grant and Steve felt it was likely a CV Axle failure, the offending sounds went away in 2 Hi. Drive home from Farmington with only an occasional growl/hum from the drivetrain.

Both CV shafts are ok, drained the front diff and found metal. LOTS. Removing the front 3rd member of the 4R stinks and was easily the worst wrenching job I've ever done. I cracked open the diff and found this.
MVIMG_20180905_155403.jpg
MVIMG_20180905_155758.jpg
IMG_20180905_155409.jpg


The ring and drive pinion look ok. I'd assume all bearings are trashed from metal consumption. Any idea what the initial failure would be to cause that damage to pinions and side gears?
What's the next step? At this point, me rebuilding is out, over my head. Junkyard? Don't want to spend an entire day at Youpull. Anyone have a 4.10 IFS front diff laying around?
Open for input and suggestions!
 
I should have stated:. Open to reasonable suggestions....:flipoff2:
 
ARB was a reasonable suggestion. Just an expensive one. I know you don't like the boneyard idea, but I think it's probably your best, and cheapest, bet. A less expensive idea might be something like a Detroit TrueTrac.
 
ARB
ARB RD132 Air Locking Differential https://www.amazon.com/dp/B004P9DDR4/ref=cm_sw_r_cp_api_9xuKBb14BJT70

Other wise pull one from UPull and swap it in. I always considered a front ARB as the final piece for that truck to finish it

I was going to install MV50 in the rear driver quarter panel and an air tank where the spare was locate from factory.
 
I've been very happy with my front ARB. Expensive, yes, but flawless and the compressor is useful.
 
Chompers - sorry to hear about your diff problems. I don't have any advice to offer, but it occurred to me that we rarely hear about such failures, especially as much as this group wheels their junk. Hopefully it was just some sort of fluke, with a bad casting or who knows what. Better luck with the next diff.
 
ARB is a $1500 solution to a $200 problem, for the expected use of that rig.
Chris if you intend to wheel it seriously like Gordy's, then yes the ARB is worth the investment. So would a solid axle or long arm kit.
If you don't see it going to hard trails, then I say stuff a junk yard diff in and go wheeling
My 94 is open in the front, locked in the back and on basically stock suspension. Its been all kinds of places it has no business being, and driven home.
There are occasions I wish it was locked up front, but still it did all kinds of trails in moab, puerco, Silverton, Telluride, etc etc.
I'll help you grab a diff front UPull if you want a hand. I'll reach out to my network of shady toyota guys too and see what they've got
 
I thought we were your network of shady Toyota guys.
 
Dumpolina knows a guy.....
 
So, after many fits and starts, the 4R is back on the road. Donor was a '98 4R with 167k on the clock. Pleased that it's done, not pleased that I put it off so long.... camping, vacation, ham radio, work and life gets in the way!
 
Chompers said:
So, after many fits and starts, the 4R is back on the road. Donor was a '98 4R with 167k on the clock. Pleased that it's done, not pleased that I put it off so long.... camping, vacation, ham radio, work and life gets in the way!
Click to expand...
Excellent!!! Now let’s go break it!!
For reals, hope we can get out some... you guys are good to wheel with!
 
Thanks! @Dumpolina We'll most likely make the 8th Jemez run, wanted to shake down the 4Runner before I chime in on the run thread. Let's break something else though!
 
If you want a back up, let me know a date & time... with a little warning I can get away. Towpig is currently down but the ‘94 is operational
 
IMG_20181124_142440.jpg
Added diff drop and went through all mounting hardware and double checked my thoroughness. No leaky, me happy. Remounted skid plate and added transfer case skidplate that has been sitting on the floor for 2+ yrs. Off-road ready!
 
Needs some dirt on it

Good timing for the diff drop kit install!
 
The weak spider gears in the 7.5 front diff are a common failure point. Also, I'm with you on the front diff R&R job being a big PITA. I have ARB RD90s in mine to (hopefully) save myself that hassle in the future.

Beefing up the diff just shifts the failure point(s)... aside from increased CV breakage with the front locker, the ADD stub shaft becomes an issue. On the 7.5 diffs the DS CV will not seat as easily or as deep as it normally does with an RD90 installed. I have snapped off a CV at the diff, I believe due to the increased protrusion, which was fun. There are pros and cons to running the RD90 on these rigs.

Glad to see you got the rig back up and running.
 
Chris,

Now that you have gone through this fun exercise, you'll now know how to do a field repair and what tools are needed. You know, "just in case"!!!
 
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