shift solenoid??
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,490
Likes: 257
From: Lake Tapps WA.
shift solenoid??
Wondering if my problem is connected with the shift solenoids? I notice off and on when I decelerate I feel a bump or slight jerk as if the trans is shifting in and out of lock up. It does it in 3rd and 4th gears but not all the time. 2001 A4, fluid is full and was changed at recommended intervals. Has been happening for the past 15k miles. Other than that it shifts and works fine. I had some changes made with HPT to firm up the shifts. Any thoughts?
Thanks
Thanks
Last edited by C5FORFUN2; Sep 9, 2012 at 11:07 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Well ,,, Any shop with a TECH2 can data log the PCM and see what the transmission is actually doing and if it is doing something that it’s not suppose to do.
I don’t work much with A4 and or A6 trans BUT,, check this out:
When the brake pedal is depressed, most auto trans come out of converter lock up. It’s very easy for the brake switch (which has multiple switches in it) to come out of proper adjustment and or become defective.
If it isn’t properly adjusted, it can tell the PCM that the brake is applied even though you did not apply the brakes.
The same switch will disengage the cruise control. Is cruise control working normally when the shift issue is taking place does your cruise control disengage??
That would be the very first place that I would look if all else is working normally.
If that doesn’t pan out, have someone who can use a TECH 2 diagnose your issue!
That will be the least expensive and most accurate method of diagnosis and repair.
Bill
I don’t work much with A4 and or A6 trans BUT,, check this out:
When the brake pedal is depressed, most auto trans come out of converter lock up. It’s very easy for the brake switch (which has multiple switches in it) to come out of proper adjustment and or become defective.
If it isn’t properly adjusted, it can tell the PCM that the brake is applied even though you did not apply the brakes.
The same switch will disengage the cruise control. Is cruise control working normally when the shift issue is taking place does your cruise control disengage??
That would be the very first place that I would look if all else is working normally.
If that doesn’t pan out, have someone who can use a TECH 2 diagnose your issue!
That will be the least expensive and most accurate method of diagnosis and repair.Bill
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
This happens when you lift off the gas or while you're off the gas and coasting?
If it happens when you lift it could be wear in some component or something like excessive backlash in the ring and pinion setup. If it happens while coasting it could be the transmission trying to shift or the converter.
I doubt it's a failing solenoid because the PCM monitors the coils. It could be dirt or something sticking though. Try holding the brake pedal down a little because that will keep the converter lockup switch open and eliminate that issue.
If it happens when you lift it could be wear in some component or something like excessive backlash in the ring and pinion setup. If it happens while coasting it could be the transmission trying to shift or the converter.
I doubt it's a failing solenoid because the PCM monitors the coils. It could be dirt or something sticking though. Try holding the brake pedal down a little because that will keep the converter lockup switch open and eliminate that issue.
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
The Cruise Control Release Switch, located to the left side of the brake pedal, is a separate switch, and is NOT a part of the Stoplamp Switch, which is located above and to the right side of the brake pedal.
The Stoplamp switch has a second pair of contacts that open when the brake pedal is depressed, which shuts off power to the A/T Shift Lock Control Solenoid. Decelerating, with no braking, will not open the control power to the solenoid.
Your transmission line pressure may have been be set too high when the shift firmness was changed. Higher than normal line pressure can result in harsh downshifts, since the 4L60E transmission does not have a vacuum modulator to control the pressure.
I would have the transmission shift firmness parameters, in the PCM, returned to the original values, before going any further with troubleshooting.
The Stoplamp switch has a second pair of contacts that open when the brake pedal is depressed, which shuts off power to the A/T Shift Lock Control Solenoid. Decelerating, with no braking, will not open the control power to the solenoid.
Your transmission line pressure may have been be set too high when the shift firmness was changed. Higher than normal line pressure can result in harsh downshifts, since the 4L60E transmission does not have a vacuum modulator to control the pressure.
I would have the transmission shift firmness parameters, in the PCM, returned to the original values, before going any further with troubleshooting.
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,490
Likes: 257
From: Lake Tapps WA.
Thank you all for the ideas. I don't have a problem with the cruise control but will check the brake switch. It does this when coasting not immediately when the throttle is lifted. I have a Tech 2 but haven't used it much for data logging. That sounds like the best thing to start with. I'll get a friend to drive and see what the data log shows.
Thanks again.
Thanks again.
