Longer drive shaft needed after RCX 6"???

[Arachnosold1er]

I just finished installing a 6" RCX lift on my 97 K1500. My driveshaft looks like it has pulled out of the tailshaft about 1-1.25 inches. Is this normal? There was no mention of possibly needing a longer drive shaft with the lift. Am I missing something here? I can't seem to find anything on this issue, except for trucks that are HUGE with tons of lift.

It didn't concern me much, but when I went to work this morning I noticed that I get a vibration or shudder when accelerating from a standstill. It goes away once I'm up to speed.

Anyone else have this problem?

 

[thz71]

You shouldnt need a longer driveshaft as for the shutter im not sure

 

[TylerZ281500]

any lift will pull your slip yoke out for it to function properly you should get it redone to be proper length. factory setting theres usually about an inch sticking out past the output seal. is your shutter only in first at take off then goes away with second? and doesnt come back around at high speeds? if its only from a stand and not in general while driving you probably have some axle wrap, easy way to tell is put the truck in park and try to rock it back and forth while looking at your pinion. if the pinion moves up or down a bit then you have axle wrap and it should probably be adressed.

 

[Arachnosold1er]

The shudder is only at low speeds and mostly when I give it a bit more gas, first gear only. It does go away once I get above 15-20mph. I have not had it past 55 yet, so I don't know if it will return at higher speeds. What's the cure for axle wrap? Ladder bars or adjust pinion angle right? I have the tapered lift blocks, so I figured they'd correct a good bit of pinion angle caused by the lift. Now I have to try to explain to the wife what to look for while I push the truck back and forth.

 

[TylerZ281500]

tapered blocks will cause a vibration because your driveline symmetry is now off, its kinda hard to explain. theres certain variants of angles that are perfectly exceptable and then theres a range where they would cause issues. first if your blocks and u bols are stretched or loose itd allow your pinion to move, if your pinion isnt tight itll hae some slop.

the only good thing about tapered blocks is it points the pinion at the tcase so that your driveshaft doesnt pull out as much when you install the lift, the poper way to do it is to really not use it at all, but most people dont have any issue. so identify if its axle wrap realted or not. secondly see if your ubolts and everything is tight, if they look bad just replace them but they should be newer since you said you recently lifted it. if none of that fixes it and you still clearly see that you ghave axle wrap you either need to live with it( not recommended) or design/ purchase some sort of track bar.

 

[Arachnosold1er]

I'm going to re-torque the u-bolts, and take the drive shaft loose from the rear end, change the pinion seal, and then see exactly how much of the slip yolk is in the tail shaft.

 

[thz71]

Changing that pinion seal is tricky be careful if you havent done it before

 

[TylerZ281500]

changing that seal wont chnge how much slip yoke is sticking out, another thing to look for while the driveshaft is out is any bushing or bearing wear on the slip yoke, that wouldnt cause your issue but might cause others.

 

[megaburb]

My 6 inch rcx lift blocks wrap bad! Mind you I'm pushing a lot of weight. I have that same shudder from a dead stop, I can also feel and see it if I go from park to drive or reverse. Traction bar is my future fix...

 

[TylerZ281500]

My 6 inch rcx lift blocks wrap bad! Mind you I'm pushing a lot of weight. I have that same shudder from a dead stop, I can also feel and see it if I go from park to drive or reverse. Traction bar is my future fix...

did you both use the blocks supplied by the rcx kit by chance? because we took those off two trucks already and swapped them out for our local offroad shops off the shelfers and it stopped.