Off-Road Tires & Lift cause Rear Diff. Damage?

Thanks for the process. Good to know. I hate butting in his business but, I do need it done correctly. I sent him this text earlier but will ask him to do it your way to be sure. And pay him accordingly. Men don’t take kindly to being told how to do something from a woman, usually. Ugh.

 

We men need warning labels. (and better attitudes)

 

No. I have a lift and 35inch tires on stock gears. 50k miles and ive even towed cars/steel trailers without any issues.

 

Great. More good news. Thank you!
Yes, I believe he has learned his lesson. He doesn’t off road so, had we ended up replacing the entire rear assembly we were going to put in a non-locking. He knows not to do it anymore and has also been told that this it. The next car is on him.

 

Sorry to be "that guy", but sonny boy didn't learn a thing. Mommy took care of it.

 

That’s ok. I know you’re out there. You’re entitled to your opinion, as am I. I have justifiable reasons for taking over on this, IMO. I’ll make damn sure it gets done right this time. Judge me if you like, I’m ok with that. I still appreciate all the help.

 

You sound like an awesome mom and very smart for doing your homework on TW the way you did.
I'm sure your kid will benefit from your awesomeness.

 

You said "put in non-locking" when that axle housing is only made to accept a locking differential. I don't think Toyota makes an non-locking one in that size axle. I just want to make sure you are aware of that.

 

Thanks for your concern. I bought a locking RD from Toyota yesterday.

I was trying to say that if we had replaced the whole rear assembly, as we were considering doing initially, we were thinking of just foregoing the locking (RD) rear assembly and, instead, installing an entire rear assembly with a non-locking RD from a salvage yard. Which can be done. But, thank you for wanting to clarify for me.

 

I wanted to read the whole way through before I commented, but my first thought was if "the proper gear lube was used?" It took 50 posts before it was even mentioned; and then by the OP. The right lube can make or break almost anything mechanical.
Don't get me wrong, there were some very good suggestions, comments, and advice. Just surprised no one mentioned lube much earlier in the thread.

 

even tho a Toyota mechanic says it was the oil, that type of damage in those pictures the gear teeth are shredded and broken which has to be from catastrophic lockup of the rear I.E. the Diff locker was engaged while driving on pavement. Toyota specs a 75w85 GL5 gear oil which is a super thin gear oil but using it wouldn't result in the damage shown here.

 

doing donuts with diff locked

 

the Toyota spec is a 75w85 gl5 probably the thinnest gear oil allowed to be used in a rear diff, ive been using the same weight oil in my truck over 100k miles and haven't had any type of rear diff issues, even if the used the 75w90 heavier which is common it wouldn't do this type of damage. even having a low gear oil situation wouldn't cause this damage it would only overheat the pinion bearing and that would be the only part that would need replacement not the whole rear.

 

From the look of the photos uploaded, I'd say it wasn't the oil that caused the damage. The gears look like it took a tremendous amount of force to chunk up that way.

 

man those gears are chewed up. I have blown 2 rings in the rear diff, both during locker engaged while offroading. my truck was really heavy. 2015 trd offroad 4x4.

#1 stock ring

https://www.tacomaworld.com/threads...12-9-16-12-11-16.462648/page-17#post-13861882


#2 4.56 ring from ECGS - they repaired under warranty.

https://www.tacomaworld.com/threads...pril-19-22-2018.474445/page-115#post-17681183

 

Gears being stripped and damaged in the picture you've shown need a tremendous amount of force loaded on them to create that type of breakage. Sheering teeth like that I've seen in Moab, UT when rock crawlers slip backwards down the face while the wheels are spinning then regain traction, like that amount of force. The weight of the vehicle + engine spinning + sudden stop = damage, i.e., sheared ring teeth

I'm a fan of giving a new driver a low hp vehicle so that they can appreciate upgrades and learn to respect what they have. A $25K truck right away isn't the best move even though safety is a concern. There are plenty of safe economy sedans out there.

Also, a full time student means student = job. He shouldn't be out socializing in a manner that destroys $2k differentials. Maybe bowling with friends for a few hrs then having your nose in the books is a better habit to form.

I'm sorry to criticize or point out some social weaknesses, but there are a lot of holes in several stories laid out in this thread, as well as, lines of thought that are a bit too convoluted.

The damage parts do not lie. They tell me how much force was require to break, therefore, what actions create that force, and subsequently behavior that led to those actions.

That's great that you told your son "Next one's on him" but why not this one? Learn the lesson immediately so its fresher to remember, not easier for push off and forget.

 

Sounds like smokey donuts and big laughs to me.

 

Your son likes fucking around doing doughnuts and general kid hooning with that rear locker. Its not the rear diff, its the driver 100%.... Have your kid pay for the repairs and id bet the diff stops blowing up.

 

You could have used wrong lube in the diff and it wouldn’t blown like that with normal driving. It definitely looks like more than just driving on pavement with the locker engaged. Very likely trying to drift or doughnuts to impress the lads.

 

I busted up the front of one of my solid axle rigs one time by hitting a ditch so hard it forced the axle back, the drive shaft didn't give enough and it loosened the pinion inside the 3rd. If he got rear ended, this could certainly happen. It was good enough to drive on but eventually it worked itself so loose it was moving to much across the gears and started eating away at the carrier.