Who has chopped down their driveshaft???

[Jimminyc]

I just installed my dana44 and realized that now my driveshaft is too short. SO im thinking about just grinding out the weld and shortening the shaft then rewelding. has anyone done this with success??? no vibes?
Next question is how much should the shaft be out of the slip yoke on the t-case? so i know how much to cut off...
input???

 

[Starboard M]

Get an SYE and new driveshaft.

Unless your an awsome welder, and have a way of balencing the ds, its going to have vibs like no other. Just do it right.

 

[goodburbon]

besides, what good would it do to shorten the shaft if its already too short?

 

[tealcherokee]

im thinking he ment too long, but, with no way to balance the shaft, it will vibe, both of mine do

 

[rupert]

i just cut mine and sleved it with 2 inch poo pipe and rewelded it , just make sure your yokes line up and weld it up. i get vibes around 80 k or 50 miles , i wouldnt do this for a dailydriven rig but for a trail spare or get ya through a pinch i think it would be ok. mind you i have a front shaft in the rear so i think the double joint probbaly eats up most of the vibes , with just a slip yoke i think it probbaly a waste of time

 

[Jimminyc]

yup...i meant too long...oops. Anyone else done this with good luck??

 

[Jeepin Jason]

nope, but I've thought about doing it with an XJ front DS to make a trail spare rear DS for our TJ...

 

[Jimminyc]

hmmm....unless someone gives me some horrible horror story, i think i may be getting out the grinder tonight and going to town.

 

[Skullver]

hmmm....unless someone gives me some horrible horror story, i think i may be getting out the grinder tonight and going to town.

So you aren't doing SYE? depending on the xfer case and the SYE used, your xfer case output shaft will be shorter with a sye, your driveshaft may not need to be shortened. If your not doing a sye, good luck with that.

 

[cal]

It will be way off balance.

Take it to a shop. Most shops hit you about $55 to shorten and rebalance the shaft. If you run an off balance shaft very long it will destroy the output bearing on your transfer case and/or the pinion bearing. I bent a shaft just a hair last year and took my pinion bearing out in about 400 miles.

 

[Rick Anderson]

Never done it, but I would "THINK" you have to cut the driveshaft down using a lathe, thats the only way to get it truly square.

Then you'd have to rebalance it.

Like mentioned, an unbalanced driveshaft will create all sorts of stress and load on the parts connected to it, you'll eat bearings, seals and parts attached to the driveshaft on either end. Anyone of those parts would cost far more than properly shortening the driveshaft.

 

[cal]

The shop I had mine cut down at cut it on a chop saw, and then used a lathe to weld it back up.

-C

 

[Jimminyc]

Cal, did you notice a vibration??? i think i just might try and see if i can feel a vibe. i would think that if i drove down the highway with no vibes, it wouldnt hurt my bearings.

 

[cal]

I did not notice a vibe no. After I had the rear end rebuilt, the gear guy put the jeep up on jacks, put it in gear, and let it idle in drive. You could SEE the runnout in the shaft, but not feel it. I would have expected it to work the other way around..

 

[87xjco]

I've done it in the past on several driveshafts and not had vibration. Couple of tricks.

Measure real carefully from end to end on the yokes and make sure they are equal before you weld it up. Cutting the tube does not require lathe accuracy because the tube fits over the yoke and and you have a little adjustment when you put the yoke into the shortened tube. What is important is that the yoke is square and is indexed so that that it lines up with the opposite yoke exactly. A long flat metal table is good for this cause you can set the yokes flat and inline before you weld them up. You will cut the tube as straight as you can and then grind off the weld on the yoke until you can slide off the section of tube that you are eliminating. Then the yoke will fit into the tube snug but you will have a little bit of adjustability there is a bout a 1/2" of yoke that fit into the tube. Also try to cut the end that is opposite of whatever end has a weight welded on (if there is one). When you weld try to do as even a weld as possible.

I did several GTO's back when I used to build them, that I installed TH400's in and I had to cut the driveshaft down. Never had a vibration probem.

 

[majic_tech]

I cut it two times and its still too damn short!

 

[Jimminyc]

Ok, so i chopped the shaft down and heres what im annalyzing. i know everyone is talking about how your shaft will drop out if your rear suspension unloads but with the stock slip yoke and about 2 inches of slip yoke out of the output shaft seal, i cant get the thing to move much at all.
I first jacked up the jeep from the middle and got both rear wheels in the air and the shaft moved maybe 1/4 inch. Then i jacked up one side of the axle and it barely moved at all.
So, is this strange? ive got about 6" of lift. no money for sye right now, but im thinking, why do it if i cant figure out a way to flex the thing so it will fall out?
feedback?

 

[cal]

It's usually done for vibe, less for fear of dropping the shaft.

How old are your springs? If they are new, you wont be able to flex them out really easy .. they take a little while to break in.

-c

 

[Jeepin Jason]

my experience is that when you flex, the driveshaft actually compresses, not extends.

 

[Jimminyc]

the springs are a couple years old. But it really dosent drop a whole lot when it unloads...but still, if at full drop it only moved about 1/4 "..then that leaves about 1 1/2 inch of shaft still engauged in the t-case...no way would it go that much more.

by the way...the output shaft has some play and a new seal didnt fix the leak...can you replace that output bearing with the t-case in the truck but just takiong the cone off???