Well starting to get cooler out and I was wondering what your guys trans temps are? I have a 278mm Circle D converter and a 40k tru-cool trans cooler with the thermal bypass installed. I did not by pass the radiator but it seems that my trans temps are on the cool side.

I put a piece of cardboard in front of the cooler and driving down the highway last night with ambient temps roughly around ~40* I could barley muster 135* with the converter locked. Even with the cardboard blocking the cooler the highest I got it was 165* when the converter was unlocked. Am I worried over nothing? I just dont want the temps to be too cool and cause premature wear seeing it isnt even really cold out yet. Just thought Id see what other guys trans temps are in the cooler climates.

 

I have a 40K TruCool and I usually run about 100 deg on short trips and upto 130 on long trips when the temps are below 40. TBSS converter, shift kit, built trans. HTH

 

165 is actually warm by my standards lol. You're fine man.

 

There are few different conditions according to my hydra-matic book for lockup. IMO just because your fluid temp is below 140* does not mean it a bad thing. As long as the TCC can function your fine. Below is some info from my book.

As long as the vehicle operating temps are appropriate for the TCC to be applied, the PCM provides the ground signal for the tcc circuit. Tcc function can happen after the engine is at 68*. The trans fluid temp must be around around 85* and will allow the lu to apply in 3rd gear. After 135* the tcc can be applied at all times in 4th gear, as apposed to having a scheduled LU apply.

I would look at what your temps are without the blocked cooler to see if it is really needed. As I mentioned above there are things that have to be met to make TCC function correctly. In my opinion 135* is not a bad thing when its cold out. Keep in mind you have a huge cooler so you should be running cooler temps when its cold out! I personally feel that no damage should occur at those temps. Vince

 

I figured with the cooler blocked that it would get a little warmer thats all. To be honest I think that is the highest I have ever seen the trans temps. I am more concerned about the lower temps.

I get what your saying. I live right by the highway and before I put the cardboard in front of the cooler the trans temp just made it to like 115*~120* seeing I just hopped right onto the highway and the converter locked right up. I guess my big question is/was...is there a temp I should want to keep it above? Is it fine as long as the converter locks up?

 

Yes I would have to say as long as the TCC is working you are good to go. With the parameters mentioned above GM did this for a reason on factory vehicles. So if your modified vehicle can operate with them more power to you!

 

Keep in mind that transmission fluid is not oil...it has different viscous properties than oil so it can operate well without being completely warmed up. Hence why in cold climates, you only see engine block heaters, not block heaters AND tranny heaters.

 

No so fast.. My Dmax locks the converter in high idle mode in park to warm the drivetrain up quicker.

Good question/discussion Jake, I was wandering too as im installing my Tru Cool soon too. If the verter locks we are good!

 

I have a P.I. 3000k 9.5inch stall and I see temps down as low as 50 below zero. I usually let my truck get warmed well before moving, but the tranny is usually around 90 or 100 before I start moving. At 30 below zero, I really have to do alot of stop and go driving to get up to 130 degrees. I ran around with the same tranny for 2 years driving it year round with the turbo on it. I run mobil 1 dex VI. I just lost some clutches at the track this summer but I don't belive it is because of premature wear in the cold weather. Just my take on it.

 

It doesn't take too long (10-15 minutes) for my trans to be above 120 degrees. In the winter, it usually runs around 135-140 degrees. I have the 40K cooler also, but without the external cold-weather bypass piece of crap.

BTW, that's the same operating temps(135-140) that it runs in the summer time.

What I'm trying to show is that my transmission runs the same normal temps in the winter that it does in the summer. Just like my engine coolant temps.