I finished my gear swap from 3.73 to 3.42.

For those who have done gear swaps, hats off to you!

For those who haven’t: You don’t know what you are missing, what a project! Now I know why shops would charge so much for a gear swap.

I had to buy some specialized tools: (You can never have enough tools)
Pinion flange holder.
Pinion depth indicator.
Magnetic dial indicator (had one of these).
In–lb dial torque wrench, (0-30 in-Lbs).
250 lb-Ft torque wrench.
3/4 inch ratchet and sockets + cheater pipe.
Shop press.
Bearing separator.
Tool for rotating the diff carrier bearing adjusters.

The hardest part with the front diff is removing the unit hub bearings. Last year I installed a locker in the front and applied liberal amounts of anti-seize to the hub bearing cases. They came apart with ease this time.

The size and weight of the rear diff components is a challenge, that rear pinion nut took well into 600 lb-ft of torque (as mentioned by another poster) to seat the bearings to the proper pre-load.

Gear mesh patters are more of an art than science, my patters weren’t “bad” per say, but perfection is in the eye of the beholder…..had a bad rear carrier bearing too…that was a bit disturbing.

How does she run? As to be expected

3.73 @2k in 6th ~62-63 MPH
3.42 @2k in 6th ~68-69 MPH

The truck feels faster while rowing the gears. Maintaining shift points at 2K the truck is moving increasingly faster at every shift point than with the previous ratios. Granted I don’t know if the ¾ mph difference in 1st a @2k is noticeable, lol. I haven’t had it above 70, but I should see ~ 200 RPM drop @75MPH.

 

Great post! My hat to is off to you. I have only swapped a couple of sets of used gears and was never totally happy with my work. I would have a hard time getting up the guts to do this one. I hope that it runs as nice as you hoped. With the GV and 3.42s you should have a very pleasant highway drive.

Jimb

 

I just rolled a set of 35"s mine

 

What did all this cost? My guess is about a 20 year payoff for this project.

 

Sounds like a BIG job,kudos to you for takin it on, CONGRATS on accomplishing it.

I'm like shilo, got 35's.


CD

 

Thanks for the support guys, hopefully she’ll hold together.

It probably cost me ~ $1500 including the tools I had to buy, but I can use those for other things. The gears themselves were less than $1000. I’ll never get a payback in better mileage; however discovering that bearing that was going bad may have saved me future expense. My front pinion seal was leaking too.

I might take off the GV and go with some bigger tires when my STTs are done.

I haven’t had it out on the highway yet, so I’ll have to see if I’m over driven in double OD at highway speed.