Trans fluid change : Best way to determine transmission temperature

[1999750il]

Hi guys,

Its time for a tranny fluid/filter change on my 1999 750il....and I believe the fluid level needs to be checked with the engine running with a fluid temperature of 80c. What is the best way to get the temperature? I dont believe my autoenginuity scan tool and or the car software will display the trans temp. In the past I would use a digital temp gun and try to get the temp from the transmission pan. I know this is a crude way of measuring the temp...what have you guys done to get the correct fluid level?
Thanks

[purplecty]

Hi guys,

Its time for a tranny fluid/filter change on my 1999 750il....and I believe the fluid level needs to be checked with the engine running with a fluid temperature of 80c. What is the best way to get the temperature? I dont believe my autoenginuity scan tool and or the car software will display the trans temp. In the past I would use a digital temp gun and try to get the temp from the transmission pan. I know this is a crude way of measuring the temp...what have you guys done to get the correct fluid level?
Thanks

INPA will display the gearbox temps in the EGS...

[1999750il]

Hi purplecty..thanks for the info. I dont have INPA..and was wondering if there is another way of determining the fluid temp or close enough for putting the correct fluid level.

[georgebest]

Hi purplecty..thanks for the info. I dont have INPA..and was wondering if there is another way of determining the fluid temp or close enough for putting the correct fluid level.

I'm using the iCarsoft BMW/Mini i910, it's $80 on Amazon
You really need something to determine the exact temp, close enough wouldnt work.

[absolutezero273]

I called a local indy who knows his BMWs, the only one I trust, about topping off my trans a few years ago because I couldn't get mine to stop growling when cold. He told me they're is no way you'll get it filled right if it is warm. He told me to fill it cold.

[purplecty]

I guess you can use a laser temp gun...

[Narlift]

^+1 get a $10 infrared gun

[COSteve]

30 to 50 C is 86 to 122F. Put your hand on the pan, if it feels more than a little warm but not hot it's in the range. Not exactly a tough target to hit.

[georgebest]

I called a local indy who knows his BMWs, the only one I trust, about topping off my trans a few years ago because I couldn't get mine to stop growling when cold. He told me they're is no way you'll get it filled right if it is warm. He told me to fill it cold.

Lol, maybe you need to find another indy

[1999750il]

Hi Guys..thanks for all the replies. I have used the digital temp gun on the pan when I have changed the fluid in the past. My concern was that the trans fluid would be at the correct temp long before the pan itself would and if that's the case...the temp would be at a higher temp and I would end up under filling the fluid. I am getting ready to do another fluid/filter change since I noticed a slight leak from the passenger side of the transmission case and I figured I would ask the group what method they used when topping off the trans fluid. Also does anyone know what the part is called that would be on the opposite side of where the transmission gear selector enters the tranny case. The part seems like neutral safety or reverse light switch. What ever it is...I am hoping its somethings that can be easily removed without having to take the valve body out of the transmission...if anyone knows what that part is PLEASE let me know. I will try to research online but always appreciate the great advice I get from this forum.
Thanks again for the help

[georgebest]

I think you need some tool to read BMW error codes anyway when owning this car, any such tool or software can read the proper temp. You should absolutlely not try to top-up when cold, all the oil would just end up on your garage floor (I have done this once, it wasnt pretty). Oil level changes a lot depending on the temperature, you should check and fill in the 30C-50C range only.
Sorry, no idea what that part could be.

[1999750il]

Hi George/all,

Thanks for the suggestions. I do have an icarsoft for my Mercedes. George...does your icarsoft have the ability to read the trans fluid temp on a 2001?? I thought our year cars were too old to have that PID
Thanks for the suggestion...I will look into the icarsoft if its able to read the trans temp on my 99 750il

[georgebest]

Hi George/all,

Thanks for the suggestions. I do have an icarsoft for my Mercedes. George...does your icarsoft have the ability to read the trans fluid temp on a 2001?? I thought our year cars were too old to have that PID
Thanks for the suggestion...I will look into the icarsoft if its able to read the trans temp on my 99 750il

Good point, sorry. I have never considered the age of your car, I have no idea if it can read yours. Mine is 2000/3 and it reads the temp without any problem. I think isoft has different models for mercedes and bmw, not sure if yours will work. Maybe what Narlift suggested then with an infrared gun? Since you have a quite wide range (30C-50C) even if it's slightly inaccurate it should still work. Just dont open the fill plug before you get to 30C, also move the selector while waiting to get to 30C so the oil gets into every chambers before you open it up. Wear some good protective gloves cause you will be working around a hot exhaust pipe. Also, check if your tool fits properly, you only have limited space there. Make sure that the car is level.
It's not a fun job, you will be working aroung a hot pipe in a narrow space and also have limited time before it gets to 50C.

[1999750il]

Thanks George...I know these fluid changes are not fun....having the car running while trying to fill til it spills and then replacing the fill plug in a hurry....all while on your back and trying to dodge the exhaust pipes..UGHH
I recently purchased a 7000 Quick jack...and I intend this trans job to be the first project with it. I will have to look into the Icarsoft for BMW....i hope it will be able to read/display the trans temp
I know these 12 cylinder engine management systems are not user friendly and most scanners will not read them properly.

[COSteve]

So according to this chart filling at 68F and then going to 122F would yield about 1/4 quart overfill assuming 8 quarts total capacity.
When I did mine I filled cold (running), waited for it to get warm and pulled the plug. A few ounces came out. Seems to shift fine.