Hello Cherokee Forum,

I have been checking this site out since getting my xj a couple years ago, but this is the first time posting, sorry for the length. Below is a picture of my jeep, bought with a mystery lift (If anyone can estimate height that would be nice too, I have 235/75/15s).



There has always been some vibrations on the highway but chalked it up to it being a jeep. Unrelated, replaced some front end components to get rid of death wobble, but also aligned and balanced tires. A bit later, the vibrations became more apparent, pulsing at highway speeds. Brought it to the shop and was told it had a bad rear pinion bearing , so I replaced it with a d35 from a junkyard myself (did a driveshaft u joint while in there) but didn't help vibrations. Got 2 new tires, balanced and aligned, but was told the rear thrust angle was off (0.8 if I remember correctly), but he matched the front to align with the off-angled rear (if I find the sheet I will post it). I just bought some new pins just in case the rear was not seated right (best guess right now). This helped vibrations a bit but they came back as a constant vibration around 65-75 mph (same as before). Been scouting around here and looked at transmission mounts (pic below) and checked other u joints but couldnt feel play. Did a 1" transfer case drop last weekend, as a cheap solution, but didnt help so reversed that back to normal. I also took pictures of driveshaft so you guys can look at angle, transfer case because it looks leaky, transmission and oil pan also to show some leaky look. Other things worth noting: I also replaced a front axle u joint, had ball joints done in the past on that side (Wound this same side up when I first got it and had it in 4 on dry land).

If you have any ideas, need more pictures, or things I could check, let me know. I dont want to put more money into upgrades on my jeep without fixing this mystery problem first. I am probably forgetting something but hopefully this is enough to start talking.




Front diff showing some leakage



Oil pan



Rear driveshaft position



TC leakage



Transmission mount (looked ok to me?)



Transmission pan with some more leakage

 

You need to replace the trans mount and probably engine mounts.

 

AS for the engine oil leak, here ya go.

http://cruiser54.com/?p=96

 

Thanks for your help, I plan on doing the transmission mount soon because I have already been down there and seems like an easy project. Once I figure out the oil leak, I will likely do the engine mounts with it because I'll be down by the adapter and sending unit anyways. Any brands/types you recommend? I'm not trying to cheap out with the $5 anchor mounts, but not sure I want to spend a ton of money on polyurethane mounts that I read can increase vibrations. Mainly DD, some light offroad/dirt road, nothing aggressive.

 

Go to Napa and get their good mounts.

We covered finding the leaks already?

 

You linked your website with the places to check, but I haven't been able to look yet. Plan on wiping all of the places you mentioned down with a rag and seeing if I can isolate where its coming from.

 

kfogart3,

At that speed, it is likely in the drive line. First and easiest thing to do is to isolate which half of the drive line the vibration is in (front or rear).

Pull the front drive shaft, and test the vehicle at speed.

Then if necessary, re-install the front shaft and pull the rear shaft and test again in 4wd.

If pulling the 2 shafts individually does not change the vibration and allow for determining which half it is in, the next likely culprit is wheels and tires. You can rotate them around to see if the vibration changes (you can do this before testing the shafts as well).

Based on just the pics of your drive shaft, I would say they are due for a rebuild (all new u-joints and a new socket yoke for the cardan joint on the front shaft).

 

Sounds like a good idea, assuming the front is easy to take out like the rear. Is it possible to run without a front axle? Id probably have to take the ujoint out and tighten just the end to the axle nut. When I did my front passenger ujoint, I noticed some corrosion/roughness in one spot, now wondering if I did something to it a couple years back when I blew out that front ujoint the first time in 4wd. Not saying I shouldn't rebuild the driveshafts, but all the ujoints seemed tight by hand.

Also, can I really run that fast in 4wd with just the front shaft in?

 

Still havent had time to clean up the possible leak spots, but took a couple pictures while filling up today. Discovered my sending unit harness is held on with a ziptie, thought the adapter area looks relatively clean, but noticed a little oil around the gasket. Also tried to get some of the passenger motor mount to get a better diea if I should replace.






Oil filter area



Motor mount



Valve cover

 

1. Not sure if that was a mistype at the beginning of your response - but you won't be removing the front axle or axle shafts. Just the front drive shaft. And yes, it is easy to remove, should only take you 20 minutes or so.

2. Yes, you can run the vehicle in 4wd with the rear drive shaft removed. Handling will be a little different, so use care. If you don't feel comfortable getting it up to speed, then don't. This is just for troubleshooting, so I would choose long straight roads with little traffic if possible.

Start with the front shaft. You may answer your questions and not have to test the other shaft (that is what I experienced).