my 4.88 rear end by genuine/superior gear has bent me over AGAIN! this time instead of working the bolts out of the ring gear, cause i used 6011 thread locker on them, it snaps a tooth off the pinion! anyone care to enlighten me in what may be going on with this rear end? 4th time in 2 years going into the rear end. how do i check the rear tubes for straight?

 

whats wrong here?

 

Are you using the correct type and amount of fluid? Are you following the proper break-in procedures after having it rebuilt? Do you have any mods that you haven't added to your sig that would cause high stress (ie. bigger tires, more powerful engine, etc...)? The 8.8 isn't exactly the strongest rearend out there, and if stressed too heavily or not taken care of it will break. Or you may just have bad luck.

Also, are you absolutely positive you have the same gear ratio in the front and rear differentials? I don't mean did you order the same ratios, I mean did you actually count the teeth yourself before the install. I think different ratios would put more stress on the axleshafts than anything, but there's no doubt it could possibly break teeth inside the differential.

 

detroit locker, 35" tires, id hope i was running bigger tires with that deep of a ratio lol. have been running 80-90 or whatever that jug was. i think it may have been something like 85- 140? i'd have to look at the jug again. ran friction modifier. did correct break in, have had numerous accounts of the ring gear walking bolts out and yes a few got chewed up pretty good. so i started welding the heads of the bolts.

i did not physically check teeth, i'd assume the first year i would have noticed some major binding.

 

after i blew mine doing a brake torque i didnt know anything about them and didnt want to make it worse. so i took it to the dealer....1,100.00 dollars later my truck is fine....always check fluid lvls before a brake torque could cost you more than a set of tires

 

I think if you were running two different ratios the gearset would not be the weakest link. It was just a thought though. Most gearsets are under some kind of warranty. They'll look at it and be able to tell if it was a defect or if it was abused. If it was a defect they'll probably replace it. It seems like all your problems are revolving around that Detroit Locker. That is a very reputable unit, but I wonder if there could be something wrong with it. Does it function perfectly? Who did the install?

I personally think you just have bad luck lol.

 

my opinion, for what it's worth, is that that pinion gear is too small. turning 35' tires is going to put a lot of stress on that pinion gear and cause it to break. is there anyone else that you know of that has run 4.88's for many miles with success?

 

There are probably hundreds of members on here who have run 4.88s for plenty of miles with no problems. I mean, that would make more sense if he were running like 50" tires with a 500 HP engine, but 35" tires are not that big and his engine is, relatively, not very powerful. You'd have a better chance of blowing a rearend with 35s and 3.55s then 35s and 4.88s.

 

use to run a richmond gear power traxx unit and it was the biggest pita, it became so warped that one side would not engage at all. swapped to a detroit full locker and my problems were reduced. it was installed correctly, i did it. was surprised how close the backlash stayed. it functioned perfectly, although i did hear a few times it unloaded and made a click with 3000lbs payload at idle. as you said with the weak link, i doubt the gears would be, but i would anticipate the transfercase to have issues first.


i had the same concern with the pinion, vocalized it with a rep who told me not to worry. bigtruck311 runs the same setup and i havent heard of him ripping up the rear. you have to consider i have a 193k on my 4.6, i think my probe makes more pony now.