hairyturtle

My 2003 Cherokee (6 cyl auto) has 225,000 miles but engine and transmission have always been fine. Suddely the tranny started slipping yesterday and within 2 miles it wouldn't budge in forward but reverse stayed normal (I had to back it up my driveway). I immediately checked the oil level which was full I also checked the linkage movement which operated as it should. After sitting overnight 'drive' is miraculously working again but I cannot trust to drive it. How could reverse be okay (but no drive) and then 24 hours later 'drive' is back again? If it was the bands, wouldn't they be permanently slippin or can they need adjustment? BTW, the vehicle had been sitting all day in 60 degree weather so it wasn't overly hot when it first starting slipping. I've rebuilt many engines but never an automatic transmission and before I replace or rebuild the tranny I was hoping for some feedback. Thank you. Turtle.

Radi

It would be interesting to put a line pressure gauge on it. Slipping that degrades into total disengagement is likely line pressure that's dropping when things warm up. Bad pump, cooked fluid, bad valve body..
Will it move if you put the shifter into 1-2?

BlueRidgeMark

What color is the fluid? Mine suddenly failed one night, and was fine the next morning. Next time it got well warmed up, it slipped badly again. Cool, it was fine. See my sig for the cure.

SatiricalHen

Never seen a 2003 Cherokee before. They stopped making them in 2001? Probably get more help if you had it in the grand Cherokee tech section if this is truly 2003 which means it would be a grand Cherokee.

cruiser54

Curious about that also.

hairyturtle

Thank you for all the replies. I tested the tranny up and down my street and it seems normal again. I really don't feel confident driving it too far from the homestead until analyzing the problem a bit more. 1) I let it idle today for 20 minutes (to get it hot) and it didn't effect forward movement so I'm not sure temp is a factor. To that point, when the slipping originally happened it had only run for about 2 minutes and engine had barely come up to temperature. 2) The oil is clean looking (pink/red) and smells fresh. In any case, I'll try BlueRidge's oil change process to rule out a possible contamination problem (TY for procedure). 3) Radi mentioned "Bad pump, cooked fluid, bad valve body ... Will it move if you put the shifter into 1-2?" Cooked fluid doesn't seem likely (pink smelled good) and it will drive forward in all positions D-1+2 so that doesn't seem to be an issue. I like the bad pump and/or bad valve body concepts but let me ask all of you, "would reverse have continued to work normally if one of these had been a problem?" I assume the pump would affect both so should that be eliminated ??? But what about a problem with the valve body ... if that is similar to conventional hydraulics (which I am somewhat familiar with) perhaps the 'forward' position of the valve had a failure ... perhaps an obstruction? But why would (or could) that be temporary? And more importantly, why would an overnight rest have resolved the problem. This thing went from total failure (in Drive, not Reverse) and then to back to normal. And yes Hen, I should have posted under 'Grand' Cherokee since that is what I have ... new to forum, I'll figure it out in time. Stil Confused!

Larry's XJ

Gee, nearly quarter million miles, wonder if it's time for a fluid change, said no one ever.

Radi

Which Cherokee, and which transmission do you have?

cruiser54

His..............

hairyturtle

The tranny is the 42RE model. Several peeps have pointed to the valve body or a stuck solenoid and they mentioned I should first try using an additive to try to clean any residues. Seafoam's 'Trans Tune' was also mentioned ... has anyone used this or any similar product? The NAPA guy said to drain enough of the existing fluid to accommodate the Seafoam and to just run it. He and I are both leary of a complet oil change due to the age-old fear of creating more of a problem (since the mileage is so high but that's a whole different discussion for another post)! So to repeat ... out of the blue, my forward drive began slipping then completely failed after 2 miles of driving (but reverse was perfect) ... then the following day everything is back to normal. When it failed, the transmission never had time for oil to get too hot (only ran for 1 minute) and the oil appears in excellent condition. Linkage cables were working fine. Therefore, does it appear to be an electrical or computer glitch or malfunction??? Electrical/electronic problems are not my cup of tea and any help would be appreciated.