Automatic transmission fluid change - temps too high?

[bloodspatteranalyst]

Hey guys

I just spent 3 hours under a lift doing an automatic transmission fluid change for the first time ever. I think all went well, I followed this guide:

http://forum.e46fanatics.com/showthread.php?t=438667

Ended up only needing about 4.5 quarts of ATF, which is weird because the kit provided 6.

I noticed a huge improvement in shifting. The car is now quick to find gears, and acceleration is vastly improved. My car also had no history of having its fluid changed and its now at 195k.

I still get a little bit of chassis movement when shifting at low speeds but I think that's mostly due to my driveline bushings being shot.

But by far my biggest concern is the temp reading I got from the pan. I used an infrared thermometer, aimed it at the pan, and it read 155F. The DIY suggests an operating temperature of 85-120F. This seemed to indicate that the fluid level was too high, but when I removed the fill plug, no ATF spilled out, which indicates that the fluid level is too low. So I topped it off and called it a day...

Other than this temperature issue, everything else seems fine. Not sure how to proceed. If any of you have experience with this, let me know!

EDIT: I used Redline D4 ATF, just fyi

[Pip]

Really happy D4 worked for you. Not sure how to proceed with the temp, but fluid level seems right if the car was running when you did the last top off.

[bloodspatteranalyst]

Thanks, Pip. I'm actually going to go back and do another complete tranny flush. I'm thinking the weird temps could be because the old fluid hasn't been completely drained and is mixing with the new fluid. I don't know what the previous fluid was but it probably wasn't D4.

The transmission is supposed to be warm but after having the car on for 5 min and shifting between gears, it was hot to the touch. You could even see the heat waves. Doesn't really make sense because the tranny is definitely filled if not overfilled, and tranny overheating is usually a symptom of low fluid levels. I didn't measure to make sure the pan was level but I assumed it would be since it was on a lift, so yeah I'm pretty clueless at this point.

HOWEVER, I did "forget" to turn the AC on to increase the idle speed of the car...but I feel like that wouldn't have been a gamechanger.

[WOLFN8TR]

I wouldn't worry about not turning ON the AC while doing the fill. As long as you got the tranny fluid up to the proper temp to check the level you should be good. When I did my tranny fluid change I used the Redline D4 ATF kit from ECSTuning. I do believe I used just about all of the fluid. The difference may be how long the car sat before you drained the pan. When I did my truck transmission I drained the pan, removed the pan and let it sit for 2 days and it was STILL dripping oil! My car was sitting in my garage for a few days and I jacked it up onto 4 ramps. When I refilled my transmission to the proper level I idled the car for about 5-10 minutes (NO AC either) and went thru the gears. It was up to the proper temp at the 10 minute mark but it never hit 155 like your car did. I would bet money on the Transmission Tstat under the Exspansion Tank being bad. When I did my entire cooling system my trans Tstat broke into pieces. To get to it you have to drain the radiator, remove the Trans Cooler and Exspansion Tank.

FYI- I wouldn't do a Trans flush, just drain and refill with Redline D4 Oil. I read up on this subject for my ZHP and Duramax and the flush could cause issues by flushing debris logged in the Transmission into areas the might cause problems later on.

Here is a link for the Tsat on Amazon:
http://www.amazon.com/dp/B00AM2952U/...=IGFL7W892OMCL

Tstat Info:
http://www.zhpmafia.com/forums/showt...anual+vs.+Auto

How the Trans Tstat works:
With regard to the lower thermostat, its purpose is to allow the ATF to be warmed when the engine is warming up, and then cool the ATF when it gets hot.
Basically, when the engine coolant is below normal operating temp, the coolant from the engine block is fed through the ATF heat exchanger, so as the engine is rising in temp, the ATF fluid is also heated.
When the engine coolant gets to operating temp, the lower thermostat operates, and now the coolant that goes through the ATF heat exchanger is coming out of the radiator, so the ATF is cooled.
The lower thermostat operates at about 80 deg C, which is slightly lower than the normal engine thermostat (about 87 deg C). What this means is that if the car engine coolant is at normal operating temp (slightly above 87 deg C) the lower thermostat is fully open, and all of the coolant going through the ATF heat exchanger is coming from the radiator.
This effect is quite noticeable if you start the car when it's up on jack stands. As the car is warming up, there is no fluid going through the radiator, but if you put your hand on the transmission pan, you will feel the temp of the fluid warming up very quickly. It's a very good design, as most of the damage done to transmissions happens when not at the correct operating temp.

[bloodspatteranalyst]

Hmm I drained and refilled while the tranny was still pretty hot. I only gave it 15 min.After all, I took it to the lift rental place I last went to and didn't have time to sit around. I let it drain for a few min but as soon as it started dripping instead of streaming, I closed the system.

Where did you read that it's bad to do a drain and fill with D4? Should I flush all over again with a different fluid?

And should I be concerned about the temps? Perhaps I would have gotten a different reading if I used a digital thermometer and stuck the sensors into the fluid, instead of aiming an infrared therm gun at the pan...

I'm really hoping my trans t-stat isn't bad because that doesn't look like something I can accomplish myself.

EDIT: also my expansion tank was replaced less than a year ago because it exploded during a pressure test.

[WOLFN8TR]

Hmm I drained and refilled while the tranny was still pretty hot. I only gave it 15 min.After all, I took it to the lift rental place I last went to and didn't have time to sit around. I let it drain for a few min but as soon as it started dripping instead of streaming, I closed the system.

That's probably why it only took 4.5 qts.

Where did you read that it's bad to do a drain and fill with D4? Should I flush all over again with a different fluid?

I think you misread my reply. Flush isn't recommended, Just drain and refill again with Redline D4 ATF.

And should I be concerned about the temps? Perhaps I would have gotten a different reading if I used a digital thermometer and stuck the sensors into the fluid, instead of aiming an infrared therm gun at the pan...

They recommend testing the fluid rather than the pan temp but I would imagine it's pretty close. It's possible my Tsat was bad when I did my ATF change and not your's. Reason being is the Tsat is suppose to remain closed upon start up. If mine was stuck open it wouldn't heat up as fast.

I'm really hoping my trans t-stat isn't bad because that doesn't look like something I can accomplish myself.

EDIT: also my expansion tank was replaced less than a year ago because it exploded during a pressure test.

Replacing the Tstat isn't that hard just time consuming. Did you replace the tank or did a shop??

[bloodspatteranalyst]

Replacing the Tstat isn't that hard just time consuming. Did you replace the tank or did a shop??

It was at a shop. I didn't own the vehicle at the time.

[WOLFN8TR]

I wonder if they replaced it?

[Dave1027]

I think the "operating temperature of 85-120F" is the temperature window you are supposed to check the fluid level at. If you filled it at 155 degrees then you let the car run too long and missed the window. In other words, You may have an incorrect level. If the tranny got too hot then you should shut the car off and let it cool then restart, check the temp and top off when in the correct temp range.

[bloodspatteranalyst]

That's odd because I had it running for no more than 5 minutes. Thanks for the insight though