So my jeep has a peculiar vibration issue. I feel a slight vibration at highway speeds. It definitely gets worse upon slowdown, and worse yet when coming to a stop. It does this in gear or in neutral. I had bad brakes so I started with that since it needed to be done anyway. I replaced both the rotors and calipers and bled the system. There was no change.

I will need to look at the codes when I get home in order to post them.

I have one for the #2 glow plug, MAF, FCV (EDIT:failed open and unplugged), and a strange body one that I believe is for the bad tire pressure sensor.

The power level seems unchanged. The rear drive-shaft doesn't seem to have any play and the u-joints replaced in the last 50,000 miles; there is a little play with the front drive shaft. There doesn't seem to be any play in the front wheel bearings (hubs).

It almost feels a like a torque converter, but this shouldn't be engine/trans/torque converter related if the vibration continues with it in neutral.

Certainly sounds like U-joints. I'm on my third rear. Switched to Moog greasables after the first two OE sets failed at a lot less than 50K. No problems since.

What did you replace them with?

Unfortunately, I don't know. My ex got the Jeep in the divorce and had it done, before i bought it back from her. They aren't greasable. The jeep did go through a pretty deep water crossing about a year ago. I changed out the diff oil in both afterwards. The Jeep kinda acts like it is running rough a little when it comes to a stop, which is kinda weird...but it does the same thing in neutral. The RPMs are constant with no fluctuation....I am rather baffled by it

One more thing. I forgot to mention that I verified the FCV failed open and I unplugged it.

The first time I could see the seals were falling apart a bit but both times I didn't feel any play in them when the shaft was mounted on the vehicle. If you pull the shaft and flop the joint back and forth in both axis you'll immediately feel if the joint is bad. Real quick and easy to do. Just make sure you mark the shaft to get it back the same way.

Does the shaft on the T-Case slip yoke just slide off or is there a keeper of some sort? I haven't pulled one so don't know what to expect.

It's splined at the T-case. Snip the band on the bellows, remove the four bolts at the diff, drop it down and pull it out.

Pull off the harmonic balancer (and the serpentine belt) and go for a short drive. You will be on battery power, so don't go crazy, but you should be able to do at least 20 miles if you needed to.

If the back of the balancer shows big cracks in the rubber spacer or there are chunks missing, there's your problem.

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Bad noises = REALLY bad things.

I am somewhat confused. I get the harmonic balancer pull; I have absolutely no room for my hands in there so I would need to pull apart the front of the car as well as the radiator, intercooler, and condenser to get to it. I don't get the drive part. I doubt I can tackle this one right now because it would be a big project for me.

Also, if there was an issue, would the engine run rough at all speeds? I am just kinda lost on this course of action not that it isn't right...I just need more understanding of what is going on if this is the case. If it is a necessary check, I would need to explain it to somebody to have it done because I can't handle this kind of project right now with the other things I have going on.

Also, I had the timing belt done just 15k back so would this have been noticed during that install?

So the mechanic thinks I have a transmission shudder.

Are there any instances where the transmission will shudder under the conditions I described as well as continue to shudder once placed in neutral?

I think you already know the answer and I also think you've got a mechanic who knows how to milk you.

As for the harmonic balancer idea, does it vibrate at idle i.e. under the same conditions as when you roll it in neutral?

No, the engine does not act abnormally under an idle condition nor when I rev it to 3,000 RPM; I have to be rolling and slowing down to experience the problem. It is far worse coming from highway speeds. I thought maybe engine and/or trans mounts too.

As far as the shudder on slowdown being the trans as well as it continuing in neutral; I thought that was BS because I never heard of such a thing. However, I don't know everything so I thought I would check.

Have you or your mechanic checked the front driveshaft?
It has joints that wear out too.
Pretty easy to test too. Just remove it then take it for a drive. If the vibration goes away you've found the problem.

What about the front CV axles?

You have a driveline problem. Not a engine or transmission problem.

Heck, it could even be a bad tire or a wheel out of balance.

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They were suppose to check all the drive-line stuff today, but didn't do it...just the its the trans BS. I now need to do it myself so pulling and checking the drive-shafts is my next step. It doesn't feel like a wheel balance issue. This whole thing started with my son who is learning how to drive. Merging on to the highway at about a 15-20mph roll, he dropped the pedal and over fueled when the turbo was spooled. He hit it hard and spun the wheels a little. This all started after that. There might be more then one issue going on too. I'm thinking the shudder when I come to a stop my be a trans or motor mount issue. I think the vibration/growl at highway speed my be u-joint or possibly a shaft or pinion bearing. At least that is my guess. I am annoyed because I wanted somebody with a lift to go through all this...I guess it was too much to ask.

This is what I hate about mechanics. They won't do what you ask them or do a lot more without getting the OK first and then expect to get paid for it.

But I'd still put money on the rear u-joint. Vibration on slowdown intensifying as you approach a stop is very typical.

Here's another thread on the topic, symptoms sound familiar? viewtopic.php?f=5&t=33237

I pulled the drive shaft and one of the seals was broken. The yoke requires a considerable amount of force for it to pivot...u-joint pretty well seized and probably bent. Will get the new u-joints done today.

Was this the front or rear driveshaft? Sounds like the joint may have locked up from age and contamination. At least it seems like an easy fix.

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Over 125 CRDs currently driving with my timing belt, rockers, or ARP Studs.
Bad noises = REALLY bad things.

It was the rear on the pinion end.

U-joints installed; I did the test drive tonight and all is well...issues gone.

Thank you!!!! ...for the help!

Hey, a lot easier and cheaper than a tranny rebuild.

Time to find yourself a new mechanic?

Last weekend we installed a lift on my CRD. Long story short, for now I'm still running my old tires.

Since starting to drive it this week, I've noticed a slight vibration upon acceleration. Usually around 25-30mph and then goes away. Feels like I'm driving over rumble strip on highway, though not a lot of up and down through the suspension and I DON'T feel it in the steering wheel.

Everything on the suspension is tightened down well, I double checked all of that.

So I suspicion u-joints. I crawled under there and pushed up and down on the driveshaft, and they still feel tight. Nothing about the angles look extreme.

Because I was still running my near DONE old tires, a buddy of mine suggested maybe one was starting to throw a belt. I cycled through all four tires tonight with the assistance of my spare. And it still exists.

It hasn't been realigned, because I'm still waiting on my 3/8" spacers so I can fit my new tires.

What else could I possibly be not thinking of. Any suggestions greatly appreciated. I've experience a slight loss in power lately, so I'm just hoping it's not an engine issue. Cause and affect would tell me it's something in the steering/suspension family, or u-joints...but I'm clueless right now.

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