3.73 -->3.42 Done!
#1
3.73 -->3.42 Done!
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.
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.
#2
Congrats!
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
Jimb
#6
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.
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.
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