View Full Version : at transmission woes at 65 mph

02-25-2010, 06:41 PM
Ive been around and around. my at trans on my 85 635 euro momentarily downshifts the goes back into 4th between 65 and 70 mph. Does not do this alway, but intermittently. very frustrating. Ive been dealing with this for 3 years. adjusted the tps numerous times. its set to specs. cleaned the trans connector under the shifter. disconnected the kickdown switch. replaced the ignition switch. replaced the temp sensor, csv. afm seems fine. car works perfect except for the intermittent shifting at cruising speeds. anyone else deal with/solve this issue thanks in advance.

02-25-2010, 10:54 PM
Changed trans fluid and filter yet?

There are two electrical connections at the shift selection lever - gear selector and mode selector. Try cleaning male and felmale ends of connectors with electronics cleaner.

Joe M in WV

02-25-2010, 11:34 PM
Do you have the Sport, economy. 1,2,3 switch?

If I click the knob from econ to sport it does the same thing as
you are describing.
If you have the knob leave it in sport mode and turn off the
ignition, upon restart the knob should jump to econ.

A few thoughts here.

02-26-2010, 12:53 PM
yes, I changed the filter and trans fluid about 5 thousand miles ago. I will try the idea on the selector switch. that would be sooo cool if that aleaviated it. thanks for the help. I have cleaned the big white connector under the shifter, not sure of the other connector, maybe for selector switch itself. what do you use to clean them....

02-26-2010, 01:41 PM
Most auto parts stores carry CRC electronic contact cleaner. It comes in a small spray can and is usually located near the brake parts cleaners, etc.

Was the trans fluid change a DIY or did you get a power flush? It takes multiple DIY trans fluid changes to renew the fluid. A good portion of trans fluid remains in the coolant lines and torque converter after a gravity drain.

Chris Wright has posted a proper transmission trouble shooting guide. If simply cleaning the contacts doesn't help, then I, or someone else will track down the guide for you.

Joe M in WV

02-26-2010, 10:09 PM
thanks joe. I will redo the trans flush. I did a gravity drain, as i have heard the flushes can cause problems...