Rearend swap

[padresag]

Originally Posted by Captainfab

The 3 series carrier has the ring gear flange farther from center than a 4 series carrier.....kind of hard to describe. I don't happen to have one handy to measure. If I can find time tomorrow, I'll see if I can get a measurement and post here. The 3 series carrier will only work with 3.42 gears and higher. The 4 series carrier will only work with 3.73 gears and lower. There are no 3.54 gears for the 12 bolt, just 3.42's. The 3.54 gears are available for the Dana differentials.

the 3;54 are a dana. gmc used them
ron