How high without driveshaft for autotrac?

[RAWVORTEC]

I've got a 99 tahoe. want to put the 4" rxc lift. Will this height require a new driveshaft? If it does, can i just not ever shift into auto 4x4?

 

[SunlitComet]

have to check with lift maker about allowed height. but no you cant just stay out of auto. it has to do with design of case and shaft.

 

[98 2-DOOR]

you shouldn't need a new front drive shaft. if anything you will need to lengthen the rear. i have a 6" and had to add a coulple of inches to my rear drive shaft. front is stock length and works fine.

 

[sparg93]

I've got a 99 tahoe. want to put the 4" rxc lift. Will this height require a new driveshaft? If it does, can i just not ever shift into auto 4x4?

Raw,
You definitely need the front driveshaft RCX offers. You can use your own, but you will eventually get a nasty vibration (it gets worse w/speed) and parts will fail prematurely.

I also have a '99 Tahoe and I'm running the RCX lift (my build thread)- http://www.gmc4x4.com/topic/323-sparg93s-expedition-troll-hunter/

With regards to your rear driveshaft, you do not need a new one.

Just remember, you will also need to modify your exhaust once you complete the lift. It's a simple extension (otherwise the front driveshaft will hit it) and any muffle shop can do it for you.

 

[99TanHoe]

Last year I bought a 99' 2 door that the previous owner had installed a 6" RCX lift on. It still had the original driveshafts and the stock 3:42 gears. It did fine until I had an offroad shop regear it to 4:56. Vibration showed up front and rear with the lower gears.

First thing we did was have a custom rear shaft built (The stock shaft was too short) for it and had the rear end shimmed so that the diff yoke was more aligned with the transmission yoke.

Still had vibration in the front end so I had the same shop that built the rear shaft lengthen the front shaft and add a double cardon U-joint at the transfer case like the one that Rough Country sells.

After all that, the Hoe is vibration free. With the 3:42 gears I could run 80mph without any serious vibration, after regearing the vibration began at about 50mph.

As someone else stated its not the Autotrak mode that causes the problem, its the angle change on the front and rear drive shafts. On my Hoe, adding the extra torque from regearing multiplied the problem.

 

[sparg93]

Last year I bought a 99' 2 door that the previous owner had installed a 6" RCX lift on. It still had the original driveshafts and the stock 3:42 gears. It did fine until I had an offroad shop regear it to 4:56. Vibration showed up front and rear with the lower gears.

First thing we did was have a custom rear shaft built (The stock shaft was too short) for it and had the rear end shimmed so that the diff yoke was more aligned with the transmission yoke.

Still had vibration in the front end so I had the same shop that built the rear shaft lengthen the front shaft and add a double cardon U-joint at the transfer case like the one that Rough Country sells.

After all that, the Hoe is vibration free. With the 3:42 gears I could run 80mph without any serious vibration, after regearing the vibration began at about 50mph.

As someone else stated its not the Autotrak mode that causes the problem, its the angle change on the front and rear drive shafts. On my Hoe, adding the extra torque from regearing multiplied the problem.

Nice looking 2dr 99.

+1

on my 4dr my rear shaft was ok, but I used the rcx custom front shaft and was very impressed by the quality.

 

[bowtiefreak]

A new shaft would be needed in the front. on a 2dr, above 5-6" lift in the rear requires lengthening the drive shaft.