Today I took the '94 Regal out with the data scanner for a general health check. One of the areas involved a round trip through a local mountain pass, which is in the neighborhood of a 10 mile long, 3.5% grade. Conditions were partly cloudy, with temperatures in the 75* range.

Engine was having a grand ole time, and even at the worst of it, with demands being made of it some would consider quite unreasonable, wasn't pushing much past 200*.

Transmission temperatures as reported by the scanner, however, weren't so lucky, with much of the run north of 200, even at dead cruise, with a rise to 230* in the worst of it. The transmission also seemed unwilling to cool right back down after loads dropped off and normal cruising was resumed on flat land. It took quite a bit of time, and really didn't seem to bottom back out until hitting the stop and go traffic again.

Research on the internet has suggested the following:
4T-60s like to make a lot of heat.
Ideal temperature is 160-180*, and ESPECIALLY below 200*, not even counting that 220* is the temperature that varnish begins forming.

But ultimately, I am not sure how much attention is really warranted. External thermostatically controlled cooler is probably ideal for the desert southwest, but then again, the behavior only exhibited while over open road, which would probably only happen a few times a year, if that.

I also know that service history has not been this car'* strong suit, between 2 previous owners that sold it because they were too old to drive, and another owner that often deferred all maintenance, I imagine that the fluid isn't in the greatest shape either.

How much attention does this warrant? Thoughts/suggestions?

I'd say do a pan drop w/filter and use Dex 6 and then re-test. The synthetic fluid may help to keep things cooler.
I also add a bottle of Lubegard red- transmission protectant, that reduces temps by 10%.
If then temps are still high, yes a larger trans cooler w/ thermostatically controlled fans would be great !

Is the TC locked up the whole time? If so, then you may need to add a cooler.

TC is locking properly. For the longest time it wasn't however because the brake switch was bad, which is another arguing point for the pan drop/fluid change.

Most of the climb the TC was unlocked however due to power demands.

This is where your heat came from. I would do the drain/fill and add an external cooler. Even if you don't drive that grade often I would add it.

I agree. unlocked TC'* cause higher temps.

What the guys are saying is, when the TC is not engaged, the converter is slipping.......for example at 65 mph, with the TC engaged, typical slippage is 15-25 rpms......with no TC lockup, 150-200 rpms......this slippage is what causes the heat...under a load, even more....

And another fun part is that on the back side, it doesn't really cool down because the transmission is dragging the engine while coasting, so the transmission is set to simmer until it csn get enough throttle back under it to lock the tcc.

I have a trip planned in a couple ofweeks (250mi round trip in to the mountains) and will probably try and exchange some fluid out of it before then, and start strategizing a pan drop afterwards.

I also plan to look at where pulling it out of overdrive on the ascent fits in with the lockup strategy. If I can get lockup in third rather than unlocked in 4th in the meantime, that should hopefully keep some heat out of the tranny.

Thanks for the brainstorming so far.

You coulllllld install a switch to manually command the TC to lockup whenever you wanted.

That is an interesting idea, but implementation would be.... interesting.

I'll have to look in to that a bit more.