A4 trans problems
Thread Starter
Drifting
Joined: Aug 2015
Posts: 1,431
Likes: 9
From: Michigan
A4 trans problems
2003 vert
Purchased December 2015 with 47,000 mikes from a Toyota dealer, clean carfax
August 2016, mileage 53,200 had trans serviced, new filter and fluid
June 2017, mileage 57,250, complete transmission rebuild
March 2018, mileage 62,400, rebuild trans, replace MAF sensor
May 2020, mileage 74,500, transmission symptoms same as when rebuilt before
Symptoms: When starting from dead stop, minimum throttle, will stay in first until just past 3,000 rpm, sometimes higher. If I let off throttle before that it will shift into second.
Start from stop with more throttle seams to still hang in first too long
Cruising around 50 mph, hit throttle fairly hard, will downshift and then rev free to limiter, sometimes makes hard shift
Is it possible that the throttle position sensor could cause this?
What else could be causing this if not the transmission?
The repair shop I have used is an independent shop that I have used for about 30 years and have always been excellent, with no problems. They were stumped when I went back the second time, had never had a return in just 5,000 miles. That is why they looked for something else going on and changed the MAF.
I have no codes except left and right mirror.
I don’t race, seldom go over speed limit, a little spirited driving, but not hard on it at all.
Purchased December 2015 with 47,000 mikes from a Toyota dealer, clean carfax
August 2016, mileage 53,200 had trans serviced, new filter and fluid
June 2017, mileage 57,250, complete transmission rebuild
March 2018, mileage 62,400, rebuild trans, replace MAF sensor
May 2020, mileage 74,500, transmission symptoms same as when rebuilt before
Symptoms: When starting from dead stop, minimum throttle, will stay in first until just past 3,000 rpm, sometimes higher. If I let off throttle before that it will shift into second.
Start from stop with more throttle seams to still hang in first too long
Cruising around 50 mph, hit throttle fairly hard, will downshift and then rev free to limiter, sometimes makes hard shift
Is it possible that the throttle position sensor could cause this?
What else could be causing this if not the transmission?
The repair shop I have used is an independent shop that I have used for about 30 years and have always been excellent, with no problems. They were stumped when I went back the second time, had never had a return in just 5,000 miles. That is why they looked for something else going on and changed the MAF.
I have no codes except left and right mirror.
I don’t race, seldom go over speed limit, a little spirited driving, but not hard on it at all.
Last edited by Awkwardcrane; Jun 7, 2020 at 10:58 AM. Reason: Added last statement
Drifting
Joined: May 2007
Posts: 1,552
Likes: 324
From: Mid Ohio
Here is what I'd do first. These may not solve your problem but they are foundational things you can do yourself and for less than $5
Disconnect battery and test for proper voltage, CCA, and internal resistance
Disassemble and clean all body grounds w/wire brush (don't use dielectric grease)
Clean MAF (electrical contact cleaner and q-tip)
Check TPS and MAF electrical connectors for corrosion
Remove and inspect / clean the body to trans electrical connectors for corrosion
Turn on headlights, turn off headlights. Turn ignition on, turn ignition off (this is how I generically clear KAM for any car)
connect (good) battery.
Turn ignition on but don't start engine.
Floor the throttle twice. (programs TPS sweep)
Done
Now the car is in a mode where it has to relearn trans shifts, relearn idle, and relearn fuel trims.
If there is an improvement you most likely have an electrical gremlin.
If it makes no improvement you probably have something internally and physically wrong with the trans.
Disconnect battery and test for proper voltage, CCA, and internal resistance
Disassemble and clean all body grounds w/wire brush (don't use dielectric grease)
Clean MAF (electrical contact cleaner and q-tip)
Check TPS and MAF electrical connectors for corrosion
Remove and inspect / clean the body to trans electrical connectors for corrosion
Turn on headlights, turn off headlights. Turn ignition on, turn ignition off (this is how I generically clear KAM for any car)
connect (good) battery.
Turn ignition on but don't start engine.
Floor the throttle twice. (programs TPS sweep)
Done
Now the car is in a mode where it has to relearn trans shifts, relearn idle, and relearn fuel trims.
If there is an improvement you most likely have an electrical gremlin.
If it makes no improvement you probably have something internally and physically wrong with the trans.
Last edited by wydopnthrtl; Jun 8, 2020 at 11:44 AM.
Thread Starter
Drifting
Joined: Aug 2015
Posts: 1,431
Likes: 9
From: Michigan
Thanks, I appreciate this information very much. I will get on this and at least eliminate the possibility of an electrical problem.
I took the car to the shop and they and I are thinking if we can’t find anything they will rebuild a different case for me. Thinking it may be cracked and doesn't show until temp and pressure are up.
I took the car to the shop and they and I are thinking if we can’t find anything they will rebuild a different case for me. Thinking it may be cracked and doesn't show until temp and pressure are up.
Drifting
Joined: May 2007
Posts: 1,552
Likes: 324
From: Mid Ohio
If it were starving for fluid the revs wouldn't be delayed. Delayed shifts is either it being commanded wrongly (sensor input is off) or some mechanical problem.
From my tuning time (10+ yrs ago) I seem to recall there is a command shift time and the computer is then reading the actual shift time. It then adjusts time and pressure to try to get actual to match the commanded specs. As long as the difference is inside a window of error everything is ok. If outside of the window it'll set a check engine / trans light. And sometimes go into a limp home mode where the shifts are delayed a bit and firmer.
If there are no codes and shifting is erratic? Then I'd look for input being wrong (which is why they replaced the MAF) or a physical malfunction inside the trans.
From my tuning time (10+ yrs ago) I seem to recall there is a command shift time and the computer is then reading the actual shift time. It then adjusts time and pressure to try to get actual to match the commanded specs. As long as the difference is inside a window of error everything is ok. If outside of the window it'll set a check engine / trans light. And sometimes go into a limp home mode where the shifts are delayed a bit and firmer.
If there are no codes and shifting is erratic? Then I'd look for input being wrong (which is why they replaced the MAF) or a physical malfunction inside the trans.
Last edited by wydopnthrtl; Jun 8, 2020 at 09:32 PM.
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
Here is what I'd do first. These may not solve your problem but they are foundational things you can do yourself and for less than $5
Disconnect battery and test for proper voltage, CCA, and internal resistance
Disassemble and clean all body grounds w/wire brush (don't use dielectric grease)
Clean MAF (electrical contact cleaner and q-tip)
Check TPS and MAF electrical connectors for corrosion
Remove and inspect / clean the body to trans electrical connectors for corrosion
Turn on headlights, turn off headlights. Turn ignition on, turn ignition off (this is how I generically clear KAM for any car)
connect (good) battery.
Turn ignition on but don't start engine.
Floor the throttle twice. (programs TPS sweep)
Done
Now the car is in a mode where it has to relearn trans shifts, relearn idle, and relearn fuel trims.
If there is an improvement you most likely have an electrical gremlin.
If it makes no improvement you probably have something internally and physically wrong with the trans.
Disconnect battery and test for proper voltage, CCA, and internal resistance
Disassemble and clean all body grounds w/wire brush (don't use dielectric grease)
Clean MAF (electrical contact cleaner and q-tip)
Check TPS and MAF electrical connectors for corrosion
Remove and inspect / clean the body to trans electrical connectors for corrosion
Turn on headlights, turn off headlights. Turn ignition on, turn ignition off (this is how I generically clear KAM for any car)
connect (good) battery.
Turn ignition on but don't start engine.
Floor the throttle twice. (programs TPS sweep)
Done
Now the car is in a mode where it has to relearn trans shifts, relearn idle, and relearn fuel trims.
If there is an improvement you most likely have an electrical gremlin.
If it makes no improvement you probably have something internally and physically wrong with the trans.
Thread Starter
Drifting
Joined: Aug 2015
Posts: 1,431
Likes: 9
From: Michigan
They rebuilt the transmission a second time (two years ago) with no charge and admitted that with no codes it was likely mot to be the MAF.
Le Mans Master
Joined: May 2006
Posts: 7,867
Likes: 250
From: Hillsboro OR
The MAF has nothing to do with it.
The first thing I would check Is your trans fluid level. NOTE: To properly check the trans fluid level, the fluid MUST BE between 85 and 122 degrees F.
The A4's shift when two conditions are met, SPEED and TPS. The A4 shift points can be programmed (both upshifts AND downshifts) for all four gears.
I would find a tuner capable of setting these parameters correctly. I have been able to tune mine to a level that I was very satisfied with.
The first thing I would check Is your trans fluid level. NOTE: To properly check the trans fluid level, the fluid MUST BE between 85 and 122 degrees F.
The A4's shift when two conditions are met, SPEED and TPS. The A4 shift points can be programmed (both upshifts AND downshifts) for all four gears.
I would find a tuner capable of setting these parameters correctly. I have been able to tune mine to a level that I was very satisfied with.
Last edited by Bluefire; Jun 11, 2020 at 03:00 AM.
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Thread Starter
Drifting
Joined: Aug 2015
Posts: 1,431
Likes: 9
From: Michigan
First thing I checked was the fluid and it is good.
They didn’t say the MAF is what caused the trans to fail, just that they were looking online to see if there was any information of the computer or electric gremlins. They didn’t charge me for second rebuild.
We are now suspecting there is something wrong with the case? I don’t know a lot about automatics, but possibly a defect that only happens under higher temp and pressure.
They have only had one other failure similar to this, 20 years ago on a Dodge pickup. They ended up getting a different case that they rebuilt and the problem went away. That’s most likely what we will be doing.
I am checking grounds. Found one ground strap that is very corroded. I have a few more to check and two weeks before I can get in the shop so I don’t think it’s waisted time.
Forgot, battery was not 100%, I thought it was just 2 years old, it was over 5. Got a new one.
They didn’t say the MAF is what caused the trans to fail, just that they were looking online to see if there was any information of the computer or electric gremlins. They didn’t charge me for second rebuild.
We are now suspecting there is something wrong with the case? I don’t know a lot about automatics, but possibly a defect that only happens under higher temp and pressure.
They have only had one other failure similar to this, 20 years ago on a Dodge pickup. They ended up getting a different case that they rebuilt and the problem went away. That’s most likely what we will be doing.
I am checking grounds. Found one ground strap that is very corroded. I have a few more to check and two weeks before I can get in the shop so I don’t think it’s waisted time.
Forgot, battery was not 100%, I thought it was just 2 years old, it was over 5. Got a new one.
Last edited by Awkwardcrane; Jun 11, 2020 at 07:08 AM.