3.42 to 3.73

[GrimsterGMC]

My truck had 3.42 from the factory but was wearing 33" tires when I got it and was unlocking the TCC constantly. I re geared to 4.1 but with the 33" tires that took me back to the equivalent of 3.42 on factory tire size. This works fine for what I wanted. Tire size are an integral part of the final drive ratio so make sure you take that it consideration. I also fitted an Eaton E-Locker as the factory carrier is a weakness in the 10 bolt diffs. As mine is an 1988 it also had the 28 spline axles and the Eaton only uses 32 spline so I changed my axles to Grizzly aftermarket axles. Like kennythewelder stated replace all of your bearings etc while it is all apart, no point going back later to do it all again.

 

[Hammer_95]

Obviously changing the front gears too….right?

Obviously. I have a used 3.73 front differential that is good shape I was just going to swap and buy a 3.73 Yukon kit for the rear if it was worth it .

 

[Hammer_95]

I think the parameters for locking and unlocking of your torque converter can be altered via a tune. It might be cheaper and more effective in your case. Worth checking into.

3.73's are decent if your truck already came with them. If you're going to go to the expense and labor of 3.42 -> then yes, go ahead to 4.10's. Looks like you might be running slightly larger than stock tires, too, so that's even more reason.

Richard

Tires are stock size 1995 came with 245s or 265s mine are the 265s. I have a 3.73 front differential that’s used but in good shape. I was just going to buy a rear unit and swap it all out

 

[jaywestfall]

So would going from a stock 3.42 open differential to 3.73 with a Yukon Duragrip and new axles be good? Will always use 15" tires with no lift.