YJ having a seizure...

[dejjen]

Can't figure out what could be causing this. It only happens when first starting off - like at a stop sign or traffic light. It is extremely bad when coming in the front gate because of the starting and stopping. Whatever it is shakes the entire Jeep extremely hard then when I let off the throttle it will calm down a little (sometimes I have to let off and start back from a complete stop) and once I get going it completely goes away, even before I get into second gear. I can't tell exactly where it's coming from. The best thing I can compare it to is the shake you get when you are trying to start off in too high a gear. Any suggestions?

[boostlesstj]

sounds like a possible vaccum leak. if you've done anything under the hood around the time it started happening check that area's vaccum lines or just look around and see if you can see some cracking or breaking

[naturalbornmudder]

death wobble?

[Disco69]

death wobble?

In 1st gear?

[The_Ronster]

Death wabble is usually associated with front coil sprung jeeps. Is your steering wheel going nuts or is it more of a driveline vibration? I would guess that maybe your rear driveshaft angle is causing the problems (being that you just lifted your jeep).

Not that a YJ cant get death wobble, they can if they have a ball joint going out, loose track bar, etc. Just the sounds of low speed only vibrations seems to indicate that the driveline is out of whack. Did you lower your xfer case skid when you lifted the jeep?

[Disco69]

One thing you should check is the ball joints. Lift up your jeep and grab each of the front tires at the 6 and 12 o'clock positions, try to rock the tires back and forth. If there is play, you have a ball joint going bad.

[dejjen]

I've checked for vacuum leaks, didn't see anything. It mostly happens in 1st gear, but if I start out in second (for whatever reason) it does it then too. The track bar isn't loose because it's not even on. It did it before I took it off though, so I know that's not the problem. My steering wheel doesn't jerk around, it just seems that the Jeep is gonna vibrate apart under me. My ZJ did it when a motor mount broke, but I've checked and these appear fine. I did put the transfer case drop kit on it when I lifted it. It seems to vibrate side to side very hard until I let off and once I get going it goes away. I'll be at the meeting tomorrow so if anyone wants to look at it they can. I'll check the ball joints tonight.

[The_Ronster]

Driveline vibrations! Either you have to much or not enough drop on your xfer case. Get some 1/2" washers and play adding to the existing spacers to see if it goes away. :2thumbs:

[Disco69]

I'm thinking that might be my issue as well. I think with the MML and TC Drop, that I have too much drop. I just don't have the time to check it 1/2 washer at a time.

[dejjen]

My dad said something about a hotspot on the clutch and that I should "burnish" it? Anyone ever heard of this?

[The_Ronster]

If that was the case you should have the same problem each time you changed gears, at least momentarilly.

[akhillbille]

So it's doing it when starting right? Not at higher speeds but at lower speeds like 20mph or below? If it is I would start looking for a broke motor mount, trans mount or a mount loose. driveline vibraitons wouldn't be very noticeable at such low speeds.

[boostlesstj]

you said you checked the motor mounts, did you check the trans/t-case mount?

[The_Ronster]

So it's doing it when starting right? Not at higher speeds but at lower speeds like 20mph or below? If it is I would start looking for a broke motor mount, trans mount or a mount loose. driveline vibraitons wouldn't be very noticeable at such low speeds.

Not completely true. When I initially lifted by TJ with just a BB I got bad vibes up to 30mph then they would go away. Three spacers between the skid and the frame corrected the problem.

I do agree that a motor mount or tranny mount could do it too, but they are usually RPM related more than gear related.

[akhillbille]

The thing is if he lets off and it stops that's not driveline related unless it slows down real fast. I'm not saying it couldn't be driveline related I would check other stuff first though.

[dejjen]

It goes away before I ever even get to like 5MPH. It's just when I first start out. I did check the motor mounts because that's what I thought it was. I didn't see any broken welds but I couldn't really see into the bushing part to see if that was ok. I've not checked the tranny/transfer mounts. Don't they just sit on the plate that's bolted to the frame?

[AKMark]

Check your trans mount. It's got a rubber bushing as well and if it's torn, it's shot.

Check the bushings of the motor mounts too, I bet those are shot. I've never seen broken welds on my motor mounts, but the bushings were almost always bad, even after only a few months of wheeling when I had my YJ.

Of course, with the hood up, even in neutral, I could hit the gas on my 4.2L and see how far the engine rocked. It was far enough that the fan had trimmed the shroud to fit when the engine was cocked quite a bit to one side.

Check bushings (mounts) and report back. A good way to look at them is to see if you can see through the bushing, if you can, it's bad.

[The Bronze]

It could definitely be the clutch. Once the flywheel has interia, the subsequent shifts will be much less noticable.

[akhillbille]

If it ends at 5mph it's safe to say it's not the driveline. Check what everyone else said..

[dejjen]

In addition to the seizure, Project YJ just had a heart attack. Burned out the alternator on the trail ride All of my lights and gauges are dead. Thanks Corey and Raymond for pulling me out and Corey for seeing to it that I got home!

[jeeptj333]

Not a problem glad it made it home

[Disco69]

Goodness.

[Militiaman]

Any time

[Militiaman]

To bad we didn't get a picture of the 3 jeep chain pull with Corey as the anchor/puller seeing how he was the only one not stuck.

[jeeptj333]

Lockers are like a gift from the gods lol

[dejjen]

So I'm not sure what I was on when I checked this before, but this is the driver's side motor mount:

http://sphotos.ak.fbcdn.net/hphotos-ak-snc3/hs522.snc3/29728_384998401228_579956228_4022563_2179676_n.jpg

http://hphotos-snc3.fbcdn.net/hs542.snc3/29728_384998406228_579956228_4022564_4342466_n.jpg

There appears to be some rubber missing...

[AKMark]

That one would be toast.

[Disco69]

I drove his YJ after the meeting to see what was going on with it. It was just as he described. The best way I could describe it is as if you were starting out in 3rd gear from a dead stop. It wouldn't do it if you rev'd the engine a little higher and then let the clutch out.

That motor mount is crapified, BTW.

[dejjen]

I have no way to change this by myself, so maybe a wrenching session is in order? Guess I'll do the valve cover gasket at the same time. Does anyone with the proper equipment have space/time to help out?

[AKMark]

This shouldn't take but about thirty minutes. The valve cover is also fairly quick.

Put a jack under the motor, raise it slightly, remove the bolt to that mount. Jack engine a little bit higher, remove mount, change mount, drop engine onto mount, reinstall bolt.

I did both sides in 20 minutes last time I did my YJ several years ago.

[dejjen]

Didn't know that it'd be that easy. I thought you'd have to lift the motor with a cherry picker. Then I guess that I'd need to borrow a floor jack from someone. I only have my HiJack and some smaller bottle jacks. You're talking about putting the jack under the oilpan and lifting from there?

[jeeptj333]

pretty easy it only took me and ged about 20 minutes at the skill center when we were doing the mml

[boostlesstj]

yeah, i'd recommend using a piece of wood to spread out the load

[akhillbille]

Yep floor jack with a wood block under the oil pan. Unbolt the mounts, replace them, bolt new ones in, and let the jack down and you are done.

[Disco69]

Lift on the bellhousing with a piece of wood. It should only take about 10 minutes.

[dejjen]

I got the driver's side motor mount replaced yesterday. What a difference that made! The shaking is still there, but it's so minor now it's hardly noticeable. Might be that the passenger side needs changed out too. Schucks/O'reilly only had the driver's side in stock. They ordered the other one for me so when it comes in I'll do that one too. When I pulled the mount out it didn't look ANYTHING like the pictures. The bushing was still completely intact. There were no missing chunks or anything like the picture showed. Bad camera angle perhaps? Anyway, there was a crack in the rubber on the back side so it was still definitely the culprit. It took about an hour to do, with rusted bolts/nuts and an old school bottle jack...but I got it done. Anyway, thanks for the guidance!

One other thing, why is it that the driver's side mount only cost $18, but the passenger side mount costs $39? They look identical to me!

edit:
OK, so maybe it didn't fix the problem. Just noticed it just as strong as ever when I was backing out of my parking spot. Hmm....

[TJVigilante]

Trans mount?

[rpiereck]

Do the other side engine mount and see how it does.

[dejjen]

Did the engine mount on the passenger side and problem persists. The tranny mount looks fine. I'm lost. Anyone have time to check this out?

[AKMark]

If you work on WW, give me a call around your lunchbreak at 978-9011, stop by bldg 3000 (next to Fire Station 1) the flight sim, and we'll get it figured out.

[dejjen]

I can stop by there tomorrow, shouldn't be a problem. BLDG 3000 is one of my four main BLDGs on FWA so I can check on my equipment while I'm there! Thanks.

[AKMark]

Well, a quick look at this YJ found no abnormalities.

When you transition from no torque to the wheels to a lot of torque at the wheels the rubber in those mounts does allow for just a little flex and the motor has a tendency to vibrate just a touch especially when it drops below normal idle speed.

It's better safe than sorry, and I for one am glad there wasn't any further problem.