XJR Transmission temperature
#1
XJR Transmission temperature
I have done the MB transmission service a few times in the past (drop pan, replace filter/sleeve/gasket, refill per procedure). It has always been difficult to get the transmission temperature up to 80 C; generally takes longer than I expect. When I have checked the level on my XJR just as an occasional precaution it's usually right at 80 C after I've driven it awhile. I've never seen it higher.
Today, on a whim, I decided to check the transmission fluid level after driving to my nieces graduation and back. It was a fair amount of stop & go driving with a couple of long lights. The engine temp never went above 205 F and settled at 203 F when parked in the garage (it's between 194 F and 198 F generally while driving). When I checked the transmission fluid level it seemed a bit too high, even though it was perfect the last couple of times I checked it.
I decided to check the transmission fluid temperature and it was about 85 C.
My question: Is 85 C too high? What is considered running "hot" for the MB transmission fluid?
It shifted perfect and was wonderful to drive today, so certainly no performance problems.
Thanks,
Today, on a whim, I decided to check the transmission fluid level after driving to my nieces graduation and back. It was a fair amount of stop & go driving with a couple of long lights. The engine temp never went above 205 F and settled at 203 F when parked in the garage (it's between 194 F and 198 F generally while driving). When I checked the transmission fluid level it seemed a bit too high, even though it was perfect the last couple of times I checked it.
I decided to check the transmission fluid temperature and it was about 85 C.
My question: Is 85 C too high? What is considered running "hot" for the MB transmission fluid?
It shifted perfect and was wonderful to drive today, so certainly no performance problems.
Thanks,
#3
Thanks for the link, Bob.
I use a method I learned reading a number of threads on the 722.6 fluid change procedure. I use an infrared thermometer. I've tested it in various ways on "known" temperatures and found it to be very accurate. I do expect that the average temperature of various points on the surface of the pan (the method I use) is probably still a few degrees off from the fluid temperature but accurate enough to get the fluid level pretty darn close.
Since I had no "trans temp" warning lights and everything worked perfectly it really just raised the question "what temperature is considered too high?".
I googled for a while thinking it would be a simple specification to find; not so much.
At what temperature range should I be concerned that the unit is running too hot? If my baseline (admittedly using the infrared thermometer) is 80 C then what increase from that should concern me?
I use a method I learned reading a number of threads on the 722.6 fluid change procedure. I use an infrared thermometer. I've tested it in various ways on "known" temperatures and found it to be very accurate. I do expect that the average temperature of various points on the surface of the pan (the method I use) is probably still a few degrees off from the fluid temperature but accurate enough to get the fluid level pretty darn close.
Since I had no "trans temp" warning lights and everything worked perfectly it really just raised the question "what temperature is considered too high?".
I googled for a while thinking it would be a simple specification to find; not so much.
At what temperature range should I be concerned that the unit is running too hot? If my baseline (admittedly using the infrared thermometer) is 80 C then what increase from that should concern me?
#5
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motorcarman (06-09-2018)
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