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Ok, so this is really about the Tahoe but I have a question. I looked but can not seem to find any info on what the minimum operating temp should be for our transmissions (since both the Crew and the Tahoe use versions of the same one) It has been single digits with a wind chill of about -11 for the last couple of days here. In the cold weather the transmission does not want to hold cruise speed, I have to downshift using the throttle on hills. Yesterday the highest trans temp recorded by the scanguage was at 72mph registering 102, in stop and go traffic on the way home in the snow storm it was averaging 89. I have the high capacity plate style trans cooler in the Tahoe that came as part of the towing package. Any ideas? should I try to get the temp up some by blocking that cooler for the winter?

Personally , I would not get too excited as long as it meets the minimum temperature for operation. For my truck that is 73 degrees. That is where the converter finally locks after warm up, so that is my assumption.

In extremely cold weather a winter front is something I might consider. You really need to keep an eye on them as it is easy to go too hot if you are not paying attention. if it is a short term thing, I don't think I would bother.

One thing that popped to mind is the switch I added to keep the converter from locking. Torque Converter Control That might help it maintain operating temp?

I knew the specs for the transmission has 75 degrees listed as the lockup temp so yours sounds about right. What concerned me a bit was that the trip home yesterday was in 4wheel drive with the trans locked into 3rd. At speeds of 40mph max I sort of expected the temps to reach a little higher. TCC mod a bit much right now working in the driveway with a whopping 16 degrees forecast today. I might go with the down and dirty cardboard and zip ties just across the trans cooler to see if that helps with the shifting. With the scanguage I do keep a good eye on the trans temp and the water temp gauge on the dash is sitting at a good point right about 180 so I don't think I want to block the entire grill although that would help on warm up.

Brian, You may actually find your temps run cooler as a general rule as you drive slower in a lower gear. Unless you were pulling heavily at 40mph the increase in engine rpm will also result in an increase in oil flow in the trans thus circulating more through the tranny as well as the cooler. Increased power available is not the only reason to lock out higher gears. Reduced temps which kill a tranny if allowed to rise too high are also an important benefit. As Brule said anything above 75F on trans temp is okay lower than that and you should perhaps have a cold front to assist.

04crewvt wrote:I might go with the down and dirty cardboard and zip ties just across the trans cooler to see if that helps with the shifting.

I think it's worth trying out.

Try covering half of the cooler first and see if you OD condition improves and if not try covering the whole thing and see what happens.

Steve

If the problem persists, you could always try switching out the cooler to a different style. The one I have from B&M prevents overcooling and it is around $50.