Transmission sticks only in cold weather

transmissions

#1

Help! I have a 1999 Jeep Grand Cherokee Laredo with a two wheel, rear wheel drive transmission with 78,000 miles on it. I know; it’s awful in the snow!



Everything works well except that the automatic transmission sticks in cold weather (50 degrees or colder). I have to drive the car 2 or 3 miles before it will shift into a higher gear. It gets really bad in 30 degree weather or cooler.



I’ve taken it to a Jeep dealership and local mechanic. Both think that I don’t need to do anything about it because (1) they don’t know what is wrong and (2) the transmission doesn’t slip once the car is warmed up.



Any help is appreciated. I had the transmission fluid changed.




#2

Interesting, a dealer and a tranny shop that don’t want to charge you for something big.

So, it stays in LOW until it’s warmed up. I’d say it has a sticky valve. Try a can of Trans-X or Seafoam and see what happens. Miracle in a can… Doesn’t sound like you can hurt it.

Another thought. Which fluid type did you use when it was changed?


#3

Good advice from prior post; the likelihood of a sticking valve body in the transmission is about 100% Short of a rebuild, using a good additive to try to free it up is about all you can do - and Trans X is very good. One other idea, if your previous transmission service was not a “complete fluid exchange” - as opposed to a drain and refill - consider spending the $75 -$100 required to have all of the fluid removed and replaced with fresh -including the max recommended amount of a Trans X type additive - usually about 10% of total fluid capacity. A typical drain and refill only removes about 1/2 of the old fluid. Suerte!


#4

I doubt very highly that you are looking at a valve body issue. 90% of the time cold weather issues are because of the rubber clutch piston seals. With age, these seals harden and allow ATF to pass by them instead of retaining the fluid behind the piston. As the trans warms up, the seals soften and will seal. This is why the trans operates well when warm. Tell me some more information. Do you have problems engaging reverse?? Where is the shifting problem ocurring?? Is it the 1-2 shift, the 2-3 shift or the 3-4 shift or all of them?? You can pour a can of Berrymans Chemtool in the trans, this will help soften the seals when the trans is cold. With the age of the trans you might want to let it warm up a minute or two in the colder weather. Since this transmission will not circulate the ATF while the trans is in Park, I would set my parking brake and allow the trans to warm up in Neutral for a minute or two prior to driving. This will allow the fluid to start to warm up and also charge the converter with ATF.

Hope this helps some.

transman


#5

Unlikely, but make sure the transmission fluid level is not too high.


#6

Hi guys. Thanks for the advice with my car.

I don’t know if anyone actually drained the entire transmission fluid or not. I’ll give that a try.

As for when it sticks, it’s definitely the 1-2 shift and somewhat the 2-3 shift. The engine will make a “whirrring” sound and stick at 25/30 mph. If I keep hitting the gas, the RPMs go high. Once I get through the 1-2 shift, the 2-3 shift isn’t too bad. After driving 5 to 7 minutes, it never sticks or slips when I’m driving unless I let the car sit for several hours. And, I don’t have a problem engaging in reverse (at least that I know about).

Can you replace the rubber clutch piston seals? I trust that’s fairly expensive. I haven’t tried to let it warm up in neutral because it’s usually too cold out and I’m impatient. But, I’ll give that a try too.

Thanks for all of your help.

  • Dan

#7

To replace the piston seals you have to remove, disassemble, inspect, and reassemble the transmission. Usually at this time a complete rebuild is done with replacement of friction components, seals, seal rings, gaskets, and worn hard parts.


#8

When was the last time the transmission fluid was changed? These transmissions are rather finicky about the fluid. It’s definitely time to change the fluid if you haven’t done it before (read the owner’s manual to find the transmission service interval and follow it). Don’t put any additives into the transmission. Definitely don’t use any transmission fluid other than ATF+4 (this is a full synthetic fluid). There are NO other fluids that are compatible with this transmission.

Try this before you try any other remedies.


#9

How is the transmission cooler controlled on this car? If it is controlled and is overcooling that could contribute to the problem,


#10

This is an inherent problem with Jeep trans…esp. 2X4 Automatics. I have same issue with a 96 Grand Cher. Larado. Wholesaler askes a dealer friend of mine…“does the trans slip” on every Jeep they take on trade that they send to auction. Sounds to me like Jeep has a major issue they do not want to face.