Tranny Questions
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Joined: May 2011
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Tranny Questions
98 coupe with an A4 that just had a tranny R&R with a 2300 stall. Couple of questions:
1. The transmission is running 15-20 degrees warmer than the one I pulled out of it (the OEM). Running around town (easy driving) it gets up to 180-190. I do have a Setrab cooler installed for the tranny. Could this increased temp be due to the increased stall?
2. Builder sent paperwork that came with the unit indicated tranny temps should be kept below 200. They know this tranny is going to be used at the track and keeping it under 200 degrees is IMPOSSIBLE. I assume keeping it under 200 is for maximum life, but sporadic temps above 200 (2-4 track days/year) won’t kill it (I'm talking 220-240 at the track).
3. Cruise control won't function now. No codes and fuse for cruise control is fine. ???
4. After one day of use I've got tranny fluid on the floor and all over the carriage, which appears to be coming from the top of the tranny. Installer used Dexron III as specified by the builder (non-synthetic). I assume the tranny might be a little overfilled and is venting out the tube up top?
Thanks.
1. The transmission is running 15-20 degrees warmer than the one I pulled out of it (the OEM). Running around town (easy driving) it gets up to 180-190. I do have a Setrab cooler installed for the tranny. Could this increased temp be due to the increased stall?
2. Builder sent paperwork that came with the unit indicated tranny temps should be kept below 200. They know this tranny is going to be used at the track and keeping it under 200 degrees is IMPOSSIBLE. I assume keeping it under 200 is for maximum life, but sporadic temps above 200 (2-4 track days/year) won’t kill it (I'm talking 220-240 at the track).
3. Cruise control won't function now. No codes and fuse for cruise control is fine. ???
4. After one day of use I've got tranny fluid on the floor and all over the carriage, which appears to be coming from the top of the tranny. Installer used Dexron III as specified by the builder (non-synthetic). I assume the tranny might be a little overfilled and is venting out the tube up top?
Thanks.
Racer
Joined: Apr 2013
Posts: 253
Likes: 3
More stall will increase temp, but a 2300 stall shouldn't increase it that much. What brand converter is it? We've found that many cheaper brand converters are very inefficient, which causes them to generate more heat. We see this alot with Edge converters. If a transmission is slipping it will cause temp to climb. Is your external cooler a "stacked plate" design or "tube and fin". We've actually seen "tube and fin" designs make the fluid HOTTER because of the poor design.
There are several things that will make a trans blow fluid out the vent. Overheating, overfilled, or an internal pressure leak that is pressurizing the sump.
Frank
There are several things that will make a trans blow fluid out the vent. Overheating, overfilled, or an internal pressure leak that is pressurizing the sump.
Frank
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Joined: May 2011
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Thanks, Frank. Not a "cheap" converter. It's a vigilante from Precision Industries - great stuff from my research.
The Setrab cooler used is this one - https://www.pegasusautoracing.com/pr...asp?RecID=8944.
Tranny temps after initial install dropped 15-20 from pre-install. With new tranny installed - they're up 15-20 from where they were after the initial cooler install (yes - it's still connected).
I'm suspecting an overfill, but will confirm tonight.
The Setrab cooler used is this one - https://www.pegasusautoracing.com/pr...asp?RecID=8944.
Tranny temps after initial install dropped 15-20 from pre-install. With new tranny installed - they're up 15-20 from where they were after the initial cooler install (yes - it's still connected).
I'm suspecting an overfill, but will confirm tonight.
Le Mans Master
Joined: May 2006
Posts: 7,835
Likes: 224
From: Hillsboro OR
I understand your pain. I have a H/C, A4 with a Yank 2800 stall. I started tracking the car last year so, I added a Setraub 25 plate cooler. (bypassed the radiator). Even with the added cooler my trans was getting a bit north of 250 degrees at the track. (Yes, I do shift it on the track). Last session it hit 265 degrees and the DIC said "TRANS TEMP HIGH". 
I soon realized that running the A4 on the track I would constantly be fighting the heat issue. The more I get better, the more cooling the car will need. You're correct, it is impossible to keep the trans temp <200 degrees if you track the car.
With that in mind, I pulled the trigger this week and started buying parts to swap my A4 to an M12.
I soon realized that running the A4 on the track I would constantly be fighting the heat issue. The more I get better, the more cooling the car will need. You're correct, it is impossible to keep the trans temp <200 degrees if you track the car.
With that in mind, I pulled the trigger this week and started buying parts to swap my A4 to an M12.
Racer
Joined: Apr 2013
Posts: 253
Likes: 3
I understand your pain. I have a H/C, A4 with a Yank 2800 stall. I started tracking the car last year so, I added a Setraub 25 plate cooler. (bypassed the radiator). Even with the added cooler my trans was getting a bit north of 250 degrees at the track. (Yes, I do shift it on the track). Last session it hit 265 degrees and the DIC said "TRANS TEMP HIGH".
I soon realized that running the A4 on the track I would constantly be fighting the heat issue. The more I get better, the more cooling the car will need. You're correct, it is impossible to keep the trans temp <200 degrees if you track the car.
With that in mind, I pulled the trigger this week and started buying parts to swap my A4 to an M12.
I soon realized that running the A4 on the track I would constantly be fighting the heat issue. The more I get better, the more cooling the car will need. You're correct, it is impossible to keep the trans temp <200 degrees if you track the car.
With that in mind, I pulled the trigger this week and started buying parts to swap my A4 to an M12.
You should NEVER bypass the radiator cooler. This is a sure way to get the trans to overheat.
Frank
Racer
Joined: Apr 2013
Posts: 253
Likes: 3
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Le Mans Master
Joined: May 2006
Posts: 7,835
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From: Hillsboro OR
Racer
Joined: Apr 2013
Posts: 253
Likes: 3
I can tell you that we've done extensive tests on transmission cooling. We proved years ago that fluid cools better when running through the radiator. We did many tests both with and without running the external cooler "in series". We've also tested many of the popular coolers and designs, as well as mounting placement. If air was a better cooling medium, than engines would be air cooled.
Frank