Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (http://www.jeepgarage.org/forums.php)
-   Export & Diesel Powered Jeep Models (http://www.jeepgarage.org/f79/)
-   -   2.7 Trans shuddering nag1 722.6 (http://www.jeepgarage.org/f79/2-7-trans-shuddering-nag1-722-6-a-58847.html)

Palm 04-22-2013 01:10 PM

2.7 Trans shuddering nag1 722.6
 
Hello,

I am hoping I might be able to find some answers here. I have searched this forum and the internet and have found many topics on 722.6 shudder but most have to do with RSN drone or shifting. Although I do get some RSN this is not my main issue.

I have a 2003 Grand Cherokee and ts has the Mercedes 2.7 CRD matched to a 722.6 transmission. The jeep has 65,000 miles on it.

It all started after some very heavy rain. I had to reverse up a hill and its started shuddering very bad. It would keep shuddering in fwd gears but would go away after a mile or so. The next time I noticed it was while accelerating onto a 70mph road. Under heavy acceleration it works fine until you let off the throttle. Once off the throttle it would shudder quite bad and you would also feel a drag, like if the parking brake was on slightly. The shuddering stops temporarily if you get on the throttle again. It takes about a mile or so to go away.

After searching the net I found a problem with water getting into the dipstick/fill tube where it connects to the trans. Apparently the torque converter clutch will shudder even with a small amount of water in the oil. So changed the oil 3 times (driving between changes), change the filter and gasket and cleaned the pan and magnet.

Its been about 2 weeks since I flushed the trans oil and its behaving a lot better. It will only sometimes shudder after full throttle acceleration. Its more likely to shudder after medium acceleration. Also any hard reversing or holding the brake and giving some throttle will start bad shuddering and it will take a few miles to stop.

Its def not the prop-shafts, u-joints or axles or wheels as the shuddering can happen while in gear at a full stop. Usually only in reverse though. Then when you switch to neutral or drive or park it stops. However, once it was shuddering in P R N and D (at a full stop).

One more thing to mention is when you turn the engine off there is an audible bump. This kinda makes me think and engine mount is bad maybe?

Does anyone recognize these symptoms?

Any help is greatly appreciated!

Chris.

Frango100 04-23-2013 09:39 AM

Re: 2.7 Trans shuddering nag1 722.6
 
So did you find evidence of water in the fluid? You say that if even shudders sometimes in Park or N? Can' t it be the engine which is doing it?

Palm 04-23-2013 10:58 AM

Re: 2.7 Trans shuddering nag1 722.6
 
Quote:

Originally Posted by Frango100 (Post 809907)
So did you find evidence of water in the fluid? You say that if even shudders sometimes in Park or N? Can' t it be the engine which is doing it?

No there wasn't a noticeable amount of water in the trans oil. But apparently as little as 0.5% water in the oil can cause problems. Chrysler recommends rtv on the dipstick and flushing the oil 3 times (some TSB).

Im pretty sure it is not the engine. It only vibrated in P and N once. Most of the time if its shuddering in R you just put it in N or P and it stops, put it back into R and its starts again.

Frango100 04-24-2013 09:13 AM

Re: 2.7 Trans shuddering nag1 722.6
 
So did you check the engine and transmission mounts, since you mentioned.the bump when shutting down the engine?
The torque converter clutch should.not be the problem, because its not engaged in reverse.
Did you check under the.jeep with a helper inside with its foot on the brake, if you can see/ hear/ feel something abnormal? Put chocks on the wheels for safety when doing this.

Palm 04-24-2013 12:32 PM

Re: 2.7 Trans shuddering nag1 722.6
 
Quote:

Originally Posted by Frango100 (Post 810613)
So did you check the engine and transmission mounts, since you mentioned.the bump when shutting down the engine?
The torque converter clutch should.not be the problem, because its not engaged in reverse.
Did you check under the.jeep with a helper inside with its foot on the brake, if you can see/ hear/ feel something abnormal? Put chocks on the wheels for safety when doing this.

Yeah I'm starting to think its one of the engine mounts. I did check for funny noises in the engine bay and under the car while its shuddering and because the diesel engine is quite noisy, you cant really hear anything out of the ordinary.

After a drive that's 30+ minutes it will almost always shudder in reverse while stopped. I opened the hood to look this time and I noticed the engine is vibrating quite a lot. Put it into D, N, or P and it is smooth. Put it back into R and it vibrates. That must be where the shuddering comes from.

I got a flashlight and inspected the rubber isolators and they don't look perished or anything. Is there anyway too check them besides just replacing them? (they're $200+ each and it looks like Ill need an engine lift to change them).

Thanks,
Chris.

Frango100 04-24-2013 06:48 PM

Re: 2.7 Trans shuddering nag1 722.6
 
If the rubber of the isolator is loose or cracked, its probably time to change it. But if that looks ok, then i'm not sure if the problem is there. Why would the engine only vibrate in R and not in D? Maybe because the torque moment is opposite in R?

Palm 04-24-2013 06:55 PM

Re: 2.7 Trans shuddering nag1 722.6
 
Quote:

Originally Posted by Frango100 (Post 810979)
If the rubber of the isolator is loose or cracked, its probably time to change it. But if that looks ok, then i'm not sure if the problem is there. Why would the engine only vibrate in R and not in D? Maybe because the torque moment is opposite in R?

Yeah that's what im thinking. Also why it may vibrate after acceleration, when the motor is putting drag on the drivetrain.


All times are GMT -5. The time now is 02:19 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community