XJ 5.5" rear lift problem

[mvusse]

Well, went over to my buddy's house for a bit to help him finish installing the tow hooks, and fix the rear brake line so he can drive his XJ again, but as he pulled it out of the garage we noticed a problem: the ears on the drive shaft are hitting the slip yoke because of the U joint angle being too steep. The yoke is also pulled out of the transfer case a bit more than I'd like; not enough that it will fall out, but enough to probably wear out the oil seal in short order. This is a 1990 2 door XJ with AW4/NP242 and (now) 5.5" lift rear springs. He was going to take a die grinder to the yoke to make it work as a temporary solution, but we will need to do something for the long term. A SYE kit is probably out of the question for the time being, so would a YJ slip yoke work? The way it is made it seems like it can go on a lot steeper angle, but does it use the same the same U joints and does it have the same spline count and diameter? I believe a YJ slip yoke is also a bit longer, which would be a plus. Alternatively, for added length, would this yoke work, even though he would still have to take a grinder to it, it seems to be a lot longer, but what about U joint, diameter and spline count?

[Pete M]

A YJ slip yoke is a temporary solution. Better than grinding though. Add a t-case drop kit to the YJ yoke and it's a slightly better temporary solution. A SYE is the proper method and I''m perplexed as to why he didn't see that coming. A bit of research should have told him about all the extras that need to be included in the initial cost of "going big". :redX:

[IDXJ]

As a short term help you might try putting some shims in to rotate the pinion up some. Won't help with the length but, should help some with the binding. Sounds really dangerous to drive like that though.

[DirtyComanche]

The YJ slip yoke is the same length, just it's basically ground from the factory. I have no issues grinding yokes personally, as long as you do it right there's really no strength loss. But if you need to grind them for it to work at static height - no, it's not good.

[Eagle]

5-1/2 inches is too much on an XJ for the stock drive shaft. Tell him NOT to drive it. Several years ago a friend in NAXJA bumped his lift up from 3" to 5". He went for a test drive and the drive shaft fell out half a mile down the road. Mangled the drive shaft, but fortunately didn't trash the rear pinion yoke, so a different drive shaft and he was good to go.

 

The YJ yoke is, as Pete said, a suitable compromise. It is slightly longer, and it's more open so it will operate at a higher angle without binding. Long term, your friend needs a different drive shaft and, ideally, a SYE.

[DirtyComanche]

The YJ yoke is, as Pete said, a suitable compromise. It is slightly longer, and it's more open so it will operate at a higher angle without binding. Long term, your friend needs a different drive shaft and, ideally, a SYE.

 

 

I'm pretty sure the YJ yoke is no longer. I've heard over and over again that it is, but I've measured them, and I've seen pictures of others being measured, and they weren't any longer.

 

I will consider it possible that there is more than one type of YJ yoke, and I always got the short style. :nuts: I haven't cared in a long time, so it's not like I ever tested a large audience.

[HOrnbrod]

I believe a YJ slip yoke is also a bit longer, which would be a plus. Alternatively, for added length, would this yoke work, even though he would still have to take a grinder to it, it seems to be a lot longer, but what about U joint, diameter and spline count?

 

The YJ yoke I had was 5/8" longer than my stock yoke, but like Dirty says, there are prolly variations of both.

 

On the GM yoke, I am using one of these as I needed about 1" total driveshaft length when I did my lift, and this was a cheap way to do it. But my lift was small, and I have a longbed, so the u-joint operating angles were not bad. I guesstimate this slip yoke would probably bind on your application w/o careful grinding.

[project88mj]

SYE?

 

doctor said i gots ta learnd new stuff every day

[mvusse]

Slip Yoke Eliminator.

[pingpong]

He needs a t-case drop, for right now. A long term solution is a SYE.

[Eagle]

Transfer case drop helps with the angle, but doesn't add any length.

[project88mj]

thanks

[mvusse]

Transfer case drop could help the length by lessening the angle. If you shorten the side of a right triangle, the hypotenuse also shortens. So if you drop the transfer case 1", the length driveshaft needed shortens by sqrt ( ( rise-1)²+ run² ) - rise² -run²

where rise is the height difference (straight up from the floor) between the top and bottom U-joints on the drive shaft and run is the distance (parallel to the floor) between the two U-joints.

 

I simplified a bit here, as I assumed a 1" tcase drop drops the top U-joint 1" In reality it would drop a fraction more than 1".

 

Anyway, he's dropping the Tcase 1" and taking the 2 lower leafs out of hs springs ( those pack have 9 leafs in them!). Hopefully that will drop the back down a bit, because 5.5" just looks funny with 31" tires, and solve the binding issue at the yoke. If not, he is still going to grind it until he can get a YJ yoke from a junk yard.

 

Here's a pic with the lift springs in. Front is a RE 3" lift, which will get 1.75" spacers added later this week:

 

The yoke is currently (before the upcoming changes) engaged 1 7/8" into the transfer case.

[Motion Offroad]

The YJ yoke is longer, however it is not fully splined all the way. So what you gain in length, you loose in spline engagment (so it's kind of a wash). I don't know however how much (if any) clearance the YJ yoke would have over an XJ yoke. I want to say off the top of my head it's very minimal.

 

XJ 2wd and 4wd yokes are a bit different, but one again I'm not sure how much (if any) clearance a 2wd yoke would give you.

 

A longer yoke won't solve the issue at hand. All it will do is allow for the yoke to pull out further at suspension flex. Just make sure that it's not to long as it will also push in, and you don't want it to push in to far (ie. bust the t-case). The yoke length will not change the the placement of the u-joint on the d-shaft. You'll need to do at least a TC drop.