Front drive shaft needed for over 4" lift?

[bowtiefreak]

our stock front shaft are plenty long. It is only the autotrac trucks that require a new CV shaft in he front the CV shaft runs 3 U joints to help with the extreme angle on the front shaft. But again it is onlt the autrac trucks that need this. I run a stock shaft and I've got one of the largest 6" kits on the market dropping my differential much lower than some lifts.

Edit: I forgot, this is a vibration thing. With out the CV shaft there will be a ton of driveline vibration. It gets into U joint phasing which is a pain in the ass. Matching angles of the U joints. I run a CV shaft on the rear of my truck

 

[Arctic-Rodz]

I see, but I wonder if the issue happens when you drive at highway speeds with the
4wd engaged? like 4HI on snowy/rainy roads..

Thing is, I NEVER drive with the Autotrack engaged. Im ALWAYS on 2HI, and when I do go 4HI/Low its at a very low speed like when I go on trails.

So my main question is, do i really NEED it if I dont use all time 4WD?? Anyone know for sure? Because as you all know, when you are on 2HI your front DS isnt spinning.

 

[bowtiefreak]

I do not know for sure. All I can say is many lift kits state that the new shaft is needed. Worst case try it, if it vibrates bad pull the shaft out and drive like that until you put a new shaft in

 

[Arctic-Rodz]

that sucks....

any "autotrack" guys done this before? im actually pretty surprised that no one with autotrack and a lift has chimed in...

 

[Dlong30]

TXGMC, ive got an autotrac too. from what ive gathered the problem is on the autotrac the front drive shaft spins in 2wd- i know dont ask me why lol. But it will vibrate all the time not just in 4wd. Some guys say you'll leak fluid if you pull it out for a lil while some dont. But if you want 4wd your gonna need it.

 

[bowtiefreak]

With teh stock Y pipe you need to re-route the cross over pipe around the front shaft anyway, soooo the shaft will need to come out on the way to the shop to get that done.

 

[Arctic-Rodz]

With teh stock Y pipe you need to re-route the cross over pipe around the front shaft anyway, soooo the shaft will need to come out on the way to the shop to get that done.

well, id have the lift done at a shop so ill let them worry about installing it...

---------- Post added at 08:51 AM ---------- Previous post was at 08:49 AM ----------

TXGMC, ive got an autotrac too. from what ive gathered the problem is on the autotrac the front drive shaft spins in 2wd- i know dont ask me why lol. But it will vibrate all the time not just in 4wd. Some guys say you'll leak fluid if you pull it out for a lil while some dont. But if you want 4wd your gonna need it.

how can the front drive shaft spin in 2WD mode???

Edit: I sent an email to a tech guy from Rough Country asking about this "issue" with the front DS.
He said I need it.
I asked, why? and asked him to explain.
He also said that the front DS spins to the trans case.
I said, how can that be? So the gears on the front IRS diff dont rotate? Ive gone under my truck and spun the front DS myself, and it rotates freely. If it would rotate while driving, I shouldnt be able to rotate it by hand right? That be like me trying to rotate the rear DS by hand. Also, I know youre not a GM Tech but I assume you are familiar with these vehicles. Can you be more specific?

And he never responded. Mind you, he would take 4-5 min between email to respond. I dont know about you guys but it sounds like BS to me.

 

[Dlong30]

apparently, the 246 transfer case uses a clutch system that doesnt give the front DS power unless your in 4wd but it does spin in 2wd... i had a buddy drive mine while i ran beside the truck lookin at it lol its just a big design flaw with the early autotrac

 

[bowtiefreak]

Considering the total cost of lifting a vehicle the proper way. Save up and get the shaft is what I would do. Trust me when I say doing it right from the start is much better and less stress. But like I stated before, you can always try with out getting the shaft, if it vibrates get the shaft, the swap is quick

 

[Done Deal DR]

Like I said though, "Off Road" magazine and a 4 Wheel Parts was somehow able to disconnect the front drive shafts (while still apparently being physically there). I don't have an Autotrac so I can't comment how this would be done. This may be an option until you can afford the drive shaft, but as bowtiefreak said, it's always nice to do it right the first time and have peace of mind.