Uncommanded Downshifting after warm-up:

A 1994 SL 500 with around 130k usually goes through its shifts beautifully until all is fully warmed, then will stay stuck in 2nd.



If at speed, will be a sudden uncommanded downshift to 3rd, or to 2nd. During this first misbehavior of the day, some games with shift to neutral for a couple of seconds at-speed, then back to 4th might re-achieve a 4th, or a 3rd, but only at best for a minute or two.


Same symptoms on surface streets; play the shifter games when it begins to misbehave to re-achieve a 3rd / 4th, but this only works briefly before that’s it for the day: it will then stay in 2nd.



Fluid level perfect. Indicated water temps are completely normal.
Saw no reason to mess with cable.



Since getting this at auction, I’ve done nothing but been running Auto-Rx to see if this helped. It seemed the symptoms disappeared until much longer well-after full warm up, but ultimately the same symptoms onset returned. So, the only change was of fluid character.


Without changing fluid/filter, I was biased about there being a broken or unstable part to deal with before dropping the pan, but could fluid/filter alone really have such a profound effect?


Before I do the fluid/filter change...any ideas consistent with great running while cool?


Sincerely, Mark



Here are some related posts:

http://www.peachparts.com/shopforum/tech-help/9487-300e-transmission-downshift-woes.html

http://www.peachparts.com/shopforum/diesel-discussion/228854-350sd-transmission-downshifts.html

http://www.peachparts.com/shopforum/tech-help/153952-94-e500-automatic-transmission-wierdness.html