gearheadette

So i was reading some old posts, to hopfully answer my question on why my drive shaft went out and how to prevent it from happening in the future. I was reading about a SYE, what does it EXACTLY do? The name is kinda self explanitory, but i want more details to see if that would be a good solution.

whowey

Well... looking at the condition of the U-joint caps in your picture. The U-joints were compeletely shot in that drive shaft. BTW that was a greasable U-joint. No reason for it to run dry like that.

An SYE is a Slip Yoke Eliminator. It gets rid of the slip yoke on the transfer case end of the rear drive shaft. A slip yoke is fine for a street truck. But once we lift a Jeep, the slip yoke slides further out of the transfer case. In some cases the slip yoke will actually fall off and drop the driveshaft out.

People use them to eliminate a vibration due to a U-joint running at a different angle than it had been. Over time U-joints 'learn' the angle they are run at and can vibrate when that angle is changed. Also being slightly longer it changes the angle on the drive shaft.

SeriousOffroad

An SYE not onlt eliminates the slip yoke but it also reduces the severity of the driveshaft angles by increasing the driveshaft length. Shims or rewelding the leaf spring perches will also correct drive line angles.

gearheadette

Thanks, just got the jeep not too long ago, and the guy i got it from took real good care of the engine, but i come to find out, now, that he only took care of the engine, and your right. the grease that was in the u joints are now dust! but the one that i bought is non-maintence and i greased the u joint on the front and the 2 on the front drive shaft.

BlueXJ

Please tell us you changed the driveshaft too. That torn collar was beyond reusing.

gearheadette

lol, yes, going junking today for a drive shaft and yoke

gearheadette

So I found the drive shaft. lol I went looking for one and this guy at a salvage yard said "yeah i got one, I'll take $40 for it" i told him, "ok, why dont you write that down, cause i will forget." I came back friday to get it and he was like "I never sell anyone a driveshaft for $40" I pulled out the little paper and said "well here you said you would" so i got it for $40.

but I get home and no one understands at the parts stores that my strap kit for the rear yoke is not u shaped with nuts, its a actual strap with bolts. so i go under the jeep to pull the good one off to take it in, and got the first real good look at my yoke (that i thought that i could salvage) and relized that IT'S DONE! so after taking pics of the yoke and arguing with the parts guys that i have a nut in the middle of it, they finally got the right one looked up and i now had to have it ordered, so i will get the yoke on monday and finally get my jeep back together!

The thing that sucks is that its been freakishly warm lately and as soon as pay day came and i had the money for this, the weather went cold, quick and its not letting up. The worst part is looking at the weather forcast, if i dont get it done by friday, its going to rain all next weekend. so i got to just get my rear in gear and get this done, the fun part is that I have never done this before, so I will take longer than normal to get it done, wish me luck!

BlueXJ

That nut in the center of your yoke is going to be a bear to remove without an impact gun. The new one will need to be torqued down when you replace the yoke. The torque is kinda high IIRC.
Look in your Chiltons or Haynes to find the torque setting and Good Luck.

gearheadette

The greatest thing about my job is i have a mobile shop (my work van) I got a Gas powered air compressor and all the fixens including a engine hoist mounted in the back of the van. So i can just back up to the jeep and start working. WOOO HOOO

And since i know someone is going to ask I am not saying which company i work for but i am a Lawn and Garden technician. I work on Lawn and Garden Tractors, rear engine riding lawn mowers, push mowers, tillers, gas grills, Garage door openers, excersie equiptment, and big air compressors.

BlueXJ

Good to know you have the tools and expertice to accomplish the task. Again good luck.

gearheadette

One question though, i was breifing myself by checking out the manual and it said to cover the transfercase with a bag to prevent contamination, its been sitting their open the whole time, did i damage anything??

And it said when removing the driveshaft mark the yoke to put it back the same, is that really going to make a diffrence? (cause mine fell out)

BlueXJ

Where the drive shaft slide into the transfercase has a seal and can get debris into and ATF out of it. The yoke is the sealing agent there.
As to marking the location if you get it out of sync then you may develop a vibration (unlikely) which can be cured by re-positioning the drive shaft yoke by 45 degrees each time until the vibration goes away.( may take several tries)

98XJDriver

'98 stock XJ 4WD 108K miles. Spent it's first few years in Mass. and the road salt has eaten up the rear drive shaft / ujoints / rear yoke and straps.

I've spent the evening searching this and the other Cherokee sites for info and rear drive shaft / u-joint / yoke replacement threads. I will be replacing my original rear drive shaft, u joints and rear yoke with a good used drive shaft, new yoke and yoke nut, new u-joints and new straps and strap bolts.

Some questions:

1. When the yoke and yoke nut are replaced is it necessary to also replace the crush sleeve at the same time? Got one. Just wondering if the crush sleeve is replaced or not with each new yoke and yoke nut.

2. I am not leaking oil from the diff drive shaft yoke seal...yet.But since I am going this far, I am thinking I should go ahead and replace the seal. Got one. Any reason not to do this?

3. I am confused about the whole rear drive shaft balance issue. If I mark and install the new yoke at the same spot I mark the old yoke at the diff will that make any difference in the balance? Seems to me with a new drive shaft and yoke, it is a waste of time. I'm thinking I should just go ahead and assemble it, see if it vibrates. If it does, start moving the rear yoke 45 degrees until it stops vibrating. Yes?No?

All advice is welcome.