What to do with rear end?

[Jrowdy]

Got tons of upgrades going into my 99 classic. I’ve got the bed off it currently and figured that it would be easiest to upgrade my rear end now. Just no idea what to do . I know it’s a 10 bolt. And the rpo is gt4. Have a 3” lift coming next week and plan on putting 20” wheels on it. Also tow a 16 ft lawn care trailer once a week. 140k miles. Any maintenance tips or changes to make while the beds off are appreciated.

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[arrg]

What size tires are you putting on those 20's? That's the important piece of info.

 

[Jrowdy]

The wheels come with 33s.

 

[AirMdwn]

14 bolt SF would be my advice. Plenty strong to handle the tires on and off road as well as towing a trailer. They offer a tru trac for it also that works well.

 

[PlayingWithTBI]

14 bolt SF would be my advice.

Good choice, I'd go to at least 4.56 gears with those 33s

 

[Jrowdy]

What is a true trac? And where’s the best place to get a 14 bolt sf ? Truck is also 4wd. What all needs to be done to change the gears?

 

[arrg]

What is a true trac? And where’s the best place to get a 14 bolt sf ? Truck is also 4wd. What all needs to be done to change the gears?

A Eaton truetrac is a type of limited slip differential. A 14 bolt sf is an axle from a 2500 series truck. Your 4wd truck will have to have gears swapped in the front differential to match whatever ratio you put in the rear.

 

[Jrowdy]

Gotcha, and what happens if I just keep my 3.73 gears and throw 33s on it? Is a junkyard going to be the best bet for a 14 bolt?

 

[AirMdwn]

14 bolt sf came in 1500hds as well. I ran 38s with mine on moderate to heavy trails and it did well. From my understanding, they came with 3.73s also. You can pick them from a junkyard. Look for a 6 bolt to fit the stock 4wd bolt pattern. Just count the bolts on the different cover. The tru trac is a mechanical limited slip that replaces the carrier that your ring gear attaches to.
Basically: you can get a 14 bolt sf with 3.73s that will bolt right in and match your factory gears. And they make a lsd for it. You just have to find it lol

 

[b454rat]

Up to 95 you could get 4.10s. But 3.42s and 3.73s are the most popular....