I purchased a 95 automatic back in Feb. and I am trying to find out what the operating temperature on the transmission should be. It has 31,000 miles on it and has not been abused; I know the pervious owner.

I started to notice the temperature this weekend after a little road trip the auto temp was reading 213 at about 75mph. Last night I drove the car again and the temp was reading 208 at 72 mph.
I have checked the fluid and it does not smell burt and is bright red in color.

Also I have noticed that the rmps are about 2300 at 75 mph. Is this normal? I have a 93 automatic also and it is high in comparison.

 

The car normally runs hotter than the average car. Normal operating temps are between 200- 220, on average. The raise in temperatures may be caused by an obstruction of the radiator. Check the air intake for any debris which may have been picked up during driving, plastic bags, leaves, etc. It can easily be checked visually by looking at the radiator and a/c from the front of the car.

 

I honestly don't know what is normal.

Here is a link that may provide some information:
http://www.txchange.com/heatchrt.htm

I recently installed a aux transmission cooler and temperature gauge in my '92 A4.
Even on 100+ degree days in Florida, I haven't seen the trans temp above about 170 degrees.
I never had a temp gauge on the transmission before the aux cooler, so I don't know what it did then.

Tom Piper

 

The lines or the trans part of the radiator could be blocked.

I once had something blocking the radiator trans cooler passage. It started getting way to hot and a warning light came on. I believe it was around 260 degrees when it lit up. I immediately pulled over and let it cool down. Later on I tried having the passage and trans lines flushed which did not help. I then decided to go to a B&M external cooler. I bought the biggest one that would fit in front of the condenser. My temps now stay around 170 degrees. Having lower trans temps is said to increase the life of the transmission by many years. I plan on installing a cooler in all cars I own from now on.

 

213° is to high, something is amiss. 175° is a good temp. I have a trans temp gauge and an extra cooler. Mine will run cool at a cruise and heat up in stop and go traffic. A cooler with a fan is best. As above, check the radiator and possibly trans cooler lines to it.

 

In answer to your actual question about trans temp rather than coolent temp ... my 95A4 runs about 195 - 205. I don't see this as a problem at all.

I've put almost 40,000 miles on my 95 since I bought it in March of 05 and have had no drivetrain problems at all. I use Amsoil product in the engine, trans & dif. I've had the trans fluid and filter changed twice since I've owned the car.

As to the RPM the late model C4 autos had two rear dif ratios. Stock was like a 2.59 and then for $50.00 more you could order the "high performance 3.07 rear which is what I have in my 95 and I suspect that you have the same in yours. This gives you much better acceleration but a little less gas milage.

The 95 is a great car

 

Thanks for the suggestions!

OK I have checked infornt of the radiator ----no obstructions

I have taken a water hose and washed out the front of the radiator also.

Saturday it was reading 213 to 219. It was also 102 degrees outside.

I guess this is normal?

 

Rick, how big a job was installing the cooler on your 95? Did you have to pull the radiator/fans, etc. to gain access?

I'm thinking of doing the same thing to my 96 and am wondering what's involved to see how much difference there may be between a trans cooler and the oil cooler I installed on my 86 L98.

Thanks,

Jake

 

It's an easy install. If I remember correctly, you should not have to remove anything. I'm not sure about the bottom trans line. You may also have to cut a small hole in the shroud for one of the lines depending on where you mount it.

It is mounted in front he AC condenser. B&M universal supercooler. I think I went with model #70266. #70274 is a bit larger but I was not sure if it would fit.


If you don't plan on using the trans cooler passage in the radiator radiator, you can run it straight off the metal trans lines to save some time.

 

Thanks for that and info and pics Rick. Very reassuring, since I'm now in labor minimization mode. LOL

Jake

 

Rick,
Does your coolant run slightly warmer (because of blocking the condenser) now than before you put the trans cooler in and does it effect the A/C ?
thanks

 

I would assume that the use of a heavy duty auxillary cooling fan on the external transmission cooler would be necessary if you are not going to reuse the stock transmission cooler in the radiator.

I'd think that connecting an aftermarket transmission cooler in series with the stock cooler would be better because you could have that extra transmission cooling capacity, as long as your cooling system is efficient and the coolant temps are in the 180s or lower. 180 degrees seems to be a happy medium for both transmission temps as well as coolant temps!

 

My coolant temps are still very good. Approximately 176 at night and 181 day at highway cruise in the summer. (Summer temps with A/C off) The highest temp I have seen was in heavy traffic with 116 heat index and 98 degree outside temps. The A/C was fully on and my coolant temp reached a high of 212. I also have a Dewitt radiator, my fans are programmed to turn on earlier, and I'm using a 160 stat. I have a Meziere HD EWP but it is not installed yet. I think the higher rpm's of the EWP will really help in traffic. The A/C works fine also and I have not done anything with it since buying the car in 2004. (no freon, service, etc.) Turning the A/C on does increase the coolant temps some but so far never above 212. When the A/C is turned off the temps go back down.


I was originally planning on using both coolers in series as some have suggested. So far using just the external cooler has shown to keep the trans temps lower. An extra fan has also not been necessary. My trans temps are always lower then my coolant temps. The trans temps range from 160's to 170's. I believe the highest I have seen was around 189. It gets really good airflow where it's mounted.



Here's another pic showing the cooler compared to the condenser and the amount of space it occupies.