I did a search and didn't come up with anything, so here goes. What should the temp range be for an A4 tranny under city stop and go driving? What is considered a dangerously high temp (where damage might occur as a result)?

And where would one mount an external cooler if it was deemed necessary? I see no available space anywhere that wouldn't compromise the efficiency of the components already there.

 

BTO recommends 160 F for their 700R4. The cooler you keep the fluid, the longer the transmission will last. I just installed a "very large" aluminum race radiator (Becool) and eliminated the tiny external tranny cooler some performance shop put in for me. The transmission fluid temp will rise with the coolant temp, so you need to keep the coolant temp low. In the corvette there isn't a lot of room for an external cooler without retricting flow through the radiator. Either spend the bucks for a good performance radiator or change (flush) your transmission fluid often. Preferrable both.

 

I agree there's no room for a cooler. So where did you put yours?

I seen tranny temps up over 200 degs at times in stop and go traffic. That CAN'T be good for it.

 

that is absolutley not good at all! you need an external cooler for your trannie, run it after your heat exchanger. remember anything is better than nothing the ideal temp is 150 but 160 when idling is acceptable. If you are getting as high as 200 you need to change fluid every time you change your oil. Having a manual fan switch is one way to cool your engine temps.

 

The tranny cooler that a shop installed for me did not bring the transmission fluid temperature down at all. It was a B&M mounted directly to an after market copper core radiator (front face in the middle). Since then, I've gone with the hi-perf all aluminum radiator. Some mechanical modifications need to be made to the stock housing because the hi-perf version is much fatter.

Temperature problems in the Vette are very common. Not too many want to spend $500-600 on a good all aluminum radiator, but if you want the engine and tranny to run cooler, you need to make the investment.

Sounds like you have a transmission temp gauge. Install a tranny cooler and see if there is a difference.


[Modified by Beth396, 7:42 PM 10/6/2003]

 

That really depends......A stock LT1/4 cooling system in top notch shape will keep your engine nice and cool. I installed a new stock radiator when mine started leaking, flushed the entire system, installed a 160F thermostat and re-programmed my fans. So my entiure system is pretty bone stock in terms of cooling capacity:
In 80F to 90F temperatures here I have yet to see 200F coolant/oil/ATF temp. Depending on ambient temps, my coolant runs in the 173 - 195F range, my ATF in the 150 - 195F range and my motor oil in the 180 - 200F range.

In terms of optimum temps: Coolant should be 180 - 200F, motor oil should really be 200F and ATF should be 150 to 175F for max longevity. Once you go over 200F on the ATF, it really reduces life of the fluid. I would mount the biggest ATF cooler you can fit right in front of the steering fluid cooler. Not the best spot, but it will do.


[Modified by Alex D, 3:40 PM 10/6/2003]

 

The owners manual for my 95 states that normal operating temperature for the auto tranny is considered anything up to 200 degrees. This weekend in 90 degree outside temp. I saw 222 degrees in stop and go driving and with "brisk" acceleration. When i got up to the limit of 75 mph with air on it would go down to 197 to 205 degrees.Even at steady high speed driving over 75 the trans temp remained the same. I think the big problem is that the ATF fluid does not circulate as fast when going slow. This might explain why some with the added external coolers still see high temp. when in traffic. I feel even 222 degrees is safe especially since I am using 15 quarts of Mobil 1 synthetic ATF. But I am also looking into a B&N cooler with fan.

 

have a look at the TCI site and the transmission temp/life expectancy chart here:
http://www.tciauto.com/tech_info/tra...expectancy.htm

Here is what they say:
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"How hot is too hot? The ideal operating temperature for automatic transmission fluid is between 175 and 225° F. At approximately 240° F, important additives in the ATF begin to cook. The result is the formation of varnish inside the transmission. At approximately 260° F, internal transmission seals (which are typically manufactured from a polyacrylate material) begin to harden. The end results are leaks, both internal and external, simply because the seals lose their elasticity. At approximately 295° F, transmission clutch plates begin to slip because the oil is breaking down further. At approximately 315° F, seals and clutches effectively burn out. Carbon forms in the oil and for all intents and purposes, the transmission is junk. Just for your information, a typical transmission will die within 2000 miles if subjected to 300° F+ heat."
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TRANNY OIL CHANGE MADE EASY:
It is however very easy to change the tranny fluid on the LT1/4 cars. The ATF cooler line on the top of the right hand side radiator tank is the hot oil coming from the tranny. If you want to change the oil, just disconnect it and slip a hose over the line. There is plenty of space to do this. Route that hose into a bucket with quart markings and start the car. Make sure to fasten the hose somehow to the bucket so it doesn't slip out when the oil begins to flow. Pump the old oil into the bucket. I got about 7 quarts out that way. When the oil out of the hose begins to sputter, shut the car off. Now you can take the oil pan off if you need to change the ATF filter. When I did this, there was only about 1 cup of old fluid left in the pan. After changing the filter, refill the pan with the amount you removed (read your marking in the bucket. They are actually acurate enough). Do not disconnect the hose yet! You still want to pump another 3 to 5 quarts of the fresh ATF throught the tranny and push the rest of the old fluid out of the tranny and converter. After thats done, replenish what you pumped out and you're done.

This way you will replace over 95% of the entire tranny fluid fill and if you don't need to change the filter, you can do this in much less time than an engine oil change. One tip: Do it while you are on your ramps. More oil will pump out when the car is on an incline.





[Modified by Alex D, 6:51 AM 10/7/2003]