1500 vs 2500 rear diff question

Benfromsac · October 16, 2015

So yesterday, as I was driving home, I noticed a new clunking sound coming from my 1988 GMC Sierra 4x4 half-ton rear differential. This morning I jack it up and took the cover off and noticed that half of one of the teeth have broken off of the pinion gear and another tooth next to it is cracked. I want this truck to have the ability pull a 29 foot fifth wheel trailer once in a great while around town. So my question is, do I want to upgrade the axle to a three-quarter ton axle, or should I install a different ratio pinion and ring gear set? (eg. 3.42 to a 4.11) If I upgrade the axle, which axles will be compatible with my truck? I understand that I would have to shorten my drive shaft since the nose of the differential would actually be longer if I upgrade to the three quarter ton, but could I just use a drive shaft out of a three quarter ton truck instead? Also, if I change the rear end ratio, well I also have to change the ratio up front since this is a 4x4? Obviously, expenses are a major factor in my decision, so I need to know roughly what to expect with both options. Thank you in advance for any help

barry G · October 16, 2015

there is way to put stuff together..

start with springs. If you got 4 leafs and one main, then the "heavy" half ton stuff is already good to go.

the 4.11 gets very warm, but even ebay has an aluminum finned cover for 100 bucks.

go for ac delco drums or any new ones with concentric rib in the middle..be sure they weigh 22-24 pounds if you have the ten inch inside diameter.

other than that, the driveshaft stuff, you already answered.

the only way those diffs die is being way too tall geared for the job, or weak springs or weak drums..combo of any of those.

My own had ubolts that snapped off in seconds with a cheap cutoff wheel. that is something to inspect by removing only...they have a sneaky hiding spot to wear down and stretch, hides inside at the bottom clamp.