Just pulled my rear diff and was suprised by the degree of damage. Any Ideas on what could have caused this? I do tow a boat that is 5000 lbs dry - add people, gas, beer I am probably looking at about 6000 lbs or so. Other than that though pretty normal 4x4 use.

 

Dang man, I would say the combonation of the boat and the added stress of the over-stock-size tires probably did it in. Are you running stock gear sizes?

 

are those factory gears, or aftermarkets?

 

they are factory 4.30's with the e-locker. do you really think 32 inch tires could cause this?

 

you are only rated at towing 5000.......


but i know guys running e-lockers and 38.5" tires (forget what gears he runs 4.88 or 5.29?) but he hasnt had a problem like that.

and hes hardcore

 

I knew that i was over the tow rating but didn't know what damage it would have caused. I have a tranny cooler, IPT valve body, stiffer rear OME suspension, maybe the 3rd was the weak link???

 

its not the tires so much but the weight your hauling and the S/C doesn't help, the design of the v6 8" 3rd was not meant to have that much power going to it, i would bet that the ring gear deflected enough away from the pinion to self destruct, and I'm sure that the oil temp was up there too, i think thats why Toyota used bearing cap braces on the "8.4" taco rear ends for extra strength, if you plan on using that housing again, i would have it checked for cracks and deflection, before reusing it

 

Thanks for the tip.. I got a good deal on a new factory elocker from a fellow yotatech member. Also, I am not going to be towing my boat with the runner anymore, will use a work van. Is there anything else that i may be doing (driving habits) or something with my set-up (lift, s/c, tires) that could have caused this? i just don't want to be replacing my 3rd every two years..

 

I bet your pinion bearings wore out and allowed less contact. Does your trans hit hard??

Don't toss that diff. Its good for parts or to rebuild.

DMG

 

I have a question before I offer a suggestion,

While pulling the boat out of the water and up to a parking spot, did you make any sharp turns at low speeds while the locker was acitivated?

If so, my suggestion would be never activate the locker during any towing.

I hope this answered any questions.

 

I've got an auto with the valve body rework done by IPT. It does shift pretty firmly, especially going into reverse. As far as the old 3rd goes, part of the deal for getting the new one was giving up the core.

 

I actually never engaged the locker when pulling out of the water or towing at all. I would sometimes put it into 4 lo on the steeper ramps but never had much slippage and therfore no need to lock it.

 

The place that rebuilt my 3rd told me to change the rear end fluid every year. Since there's no filter for the fluid, it's good to keep it fresh. Don't know if that's overkill but, 3 quarts of diff fluid isn't that expensive compared to a rear end rebuild.

 

Thanks. I changed it once since I bought the truck (2+years ago) and replaced it with redline synthetic. However, when I took the original fluid out, I did notice some metal shavings but was told that this was normal.

 

It occurs to me that most likely all that torque and the weight you pull may have crushed the crush sleeve past its original depth and messed up your pinion depth rather than just bearing wear causing this.

DMG

 

Yeah, I have settled on the idea that the towing of my boat was the major cause of this. I just got my new diff installed yesterday and it is running great. Went with a brand new OEM E-locker and just swapped it in. Thanks for all the suggestions, I am done towing with the Runner!!