10.5" to 11.5" Axle Upgrade - 2500HD

[johanh13]

Just in case anyone ever thought about this upgrade, I just upgraded the axle on my 2500HD 2WD Crew-cab short-bed. My pickup came with a 10.5" 14-bolt locking axle with 4.10 gears. Needless to say, the locker failed, so I found a donor vehicle with the 11.5" AAM axle, 3.73 gears, and locker. I installed this upgrade all by myself in about 5 hours. Since the 'nose' on the 11.5" is about 3" longer, you also need the rear part of the driveshaft. I took it apart at the splines. I realize that the shaft is balanced as a unit and I was a little worried that I would get vibration, but even at 100 MPH (on jack stands), there was zero detectable vibration. Am I missing anything? If you have any questions or suggestions, please post them here, and thanks for looking!!!

[George C]

your truck must of been a 6litre

[johanh13]

You got that right!

[George C]

since the medium 14 bolt was backed by the 6.0

the 11.5 was 8.1 or Dmax, your little 6.0 is now even less power turning that heavy diff but good future investement

[GasGuzzler]

Good job. Surprised "servicing" one part of a two piece shaft did not kick it out from under the truck. Good info though for your specific swap.

[johanh13]

I was told by a mechanic to check for vibration, if there was vibration, then I would have to take the whole driveshaft and get it rebalanced. I could not detect any vibration, but then I have never had a drive shaft vibrate, only wheels/tires. Does anyone have any insight on this? I initially tested it with the rear axle on jackstands, there was zero vibration, even when I accelerated up to 100 MPH. Anyhow, I used a Hypertech programmer and GPS to correct my speedometer. I have 285/75R16 tires, and with the 3.73 gears, my speedo showed 61 MPH when the GPS showed 70. I then put 3.73 in the programmer, and 31" tire height, to correct my speedo to the reading on my GPS. What do you guys think?

[GasGuzzler]

What works, works.

[Mang213]

I was told by a mechanic to check for vibration, if there was vibration, then I would have to take the whole driveshaft and get it rebalanced. I could not detect any vibration, but then I have never had a drive shaft vibrate, only wheels/tires. Does anyone have any insight on this? I initially tested it with the rear axle on jackstands, there was zero vibration, even when I accelerated up to 100 MPH. Anyhow, I used a Hypertech programmer and GPS to correct my speedometer. I have 285/75R16 tires, and with the 3.73 gears, my speedo showed 61 MPH when the GPS showed 70. I then put 3.73 in the programmer, and 31" tire height, to correct my speedo to the reading on my GPS. What do you guys think?

You'll know if there's a vibration in the ds. It will vibrate. That's how you can tell. j/k

[MYSHTBX]

It is just me or does a 100mph on jacks stands seem a bit unwise?

[Mang213]

It is just me or does a 100mph on jacks stands seem a bit unwise?

sounds like fun, while it lasted