transmission slippage

[calexander]

Have 99 automatic, with 55,000 miles - between 40 and 45 miles when cold the transmission seems to be slipping for a few seconds at a time, once the vehicle is warm the problem seems to go away. Have had the transmission fluild and filter changed at 30,000 miles, use mopar fluid. The biggest thing I ever towed was a 2 place snowmobile trailer. Has anyone else had this problem, and does anyone have any ideals on what it could be.

Thanks

 

[Joe G.]

Could be low fluid. Check it after it's up to operating temp on a level place. Let it idle, move to R, then to D, then to N, and check while it's still idleing.

 

[calexander]

First thing I checked was the fluid. It's fine! Seems to be happening when the trannys in overdrive, between 40 and 50 miles an hour. Tacking around 1500 rpm's. I say its the transmission slipping because the tach jumps about 3-4000 for 2-3 seconds and then jumps right back down. did it three or four times within 30 seconds then stopped. Does not happen under load. does not happen all the time, would like to figure it out before it get worse.

 

[Joe G.]

This may not apply since my truck is a '95 and the tranmission controls are different. Does the problem happen with the cruise control on? If it does then you may have a problem with the TPS causing the TC clutch to lock and unlock.

 

[calexander]

Thanks for the info and help but the cruise is NOT on when this is occuring.

 

[LSMITH]

PLease post a signature or list your gear ratio. I think it could be that the TC lockup is engaging and disengaging. This is fairly common and can be cured by a reflash if it is the problem.

 

[BHayes]

Sorry to hear about your transmission problems. This seems to be one of the weaker links for Dodge Diesel owners. I too have the automatic. I'm not sure gearing in the rear end with the converter locking in and out would cause the jump from 1500 to 3-4000 rpms, my truck only drops around 500 rpms at about 50 mph when the converter locks up . You did not mention if the tranmission slowly ramps up to the high rpm or if it is sudden. Does it seem like when you are driving that the transmission is put into neutral then slams hard back down to 1500 rpms? It may not be slipping, may be linkage problems. My advice, talk with a reputable dealer, I'm sure they have seen the problems your discribing. Good luck!

 

[mbrolin]

It is possible that the TC is draining fluid when sitting. This has been known to occur with these trannys. It is also possible that a seal is leaking internally.

 

[inarush76]

Could be you are experiencing the sporadic sealing of the undersized inner piston seal in the front clutch. All of the trans that I install the DTT conv and vb in get this updated seal as it can cause this type problem(front clutch must hold in 3rd and 4th). While at the speed you describe it could also be the l/u cycling due to a number of reasons. If still in warranty, have it checked out, however, the dealer if rebuilding will not use the updated seal as it is aftermarket. I have been into a couple of newly repaired(at dealer) trans and the updated seal was not there, it was the original design. It would be a good idea to have line pressure checked as part of diagnosis, have seen low pressure from factory. Good Luck



James Northum

Dtt dealer-installer

 

[Tom W]

Clean the battery terminals and see if that helps.

 

[calexander]

Thank you Tom. It's always a good idea to try the simple things first ! Cleaning the battery posts took care of the problem. Thanks to everyone else for there input. Learned lots of other info i'll probably use later. Thanks all

 

[Tom W]

Bill K told me about cleaning the battery terminals. I guess it's stray electrical spikes or something. I would think some of our electrical experts could come up with something to prevent this. It's not a big job to clean the terminals but it worries me that the control modules are so sensitive. What other problems could this cause? I'll bet there has been a lot of troubleshooting time in the dealers shop.

 

[Mr. Brewski]

Next time my wife complains about low tire pressure, I'll tell her to clean the battery cables..... Who'd've thought of that!

 

[calexander]

May be I spoke to soon. The problem disappeared as soon as I cleaned the terminals. Lasted for five days and about 250 miles, started to do again this evening. Guess I'll go to the dealer and have the codes checked out.

 

[Ramboy]

I have a '99 also and I experienced the same problem. Between 40 and 45 when, under low accelleration, the TC was shifting into lock-up, the slippage would occur. Another bad spot was between 60 -70. Dealer reflashed and no more problem.

 

[calexander]

Well, went to the dealer last Thursday, waited a week to post this to make sure, but the problem seems to have been corrected. There was an update for the computer in my year truck. Was for cold weather starting and improved towing ability. I have the code number avalible if any one needs it. When the dealer updates the computer he is required to sticker the truck with the new updated code info. Thanks everyone for their info. !!!