The Stovebolt Site Forums The Shop Area Driveline 700r4 cooling

I have tried to make sense of the information that I have been reading on this subject and still not sure whether to install this for my particular application or not?
This is my very first build and I am considering installing a heat sink type Trans/Cooler such as the Jegs Derale 13249.
http://www.jegs.com/i/Derale/259/13249/1000
My set up is stock 4.3v6 170HP with stock 700r4 Transmission. I will not be doing any racing and just want to cruise. Not sure about the Technical application of this? Would appreciate to know if Anyone knows if this would keep things ok installed near the transmission on the frame rail.

Thanks for your time & consideration.

Only as supplemental cooling. Use the radiator cooler first, then this. I wouldn't depend on it to cool the transmission oil by itself.

as on the other thread - it might do OK for occasional light use [10" is about the smallest made], but having no GVW rating on it I'd be leery of taking a chance - also, what happens in hot weather [if you get any ] when you're stuck in traffic and there's no air flow around the unit? your best bet would be to have a tube and fin unit in front of the rad ... check some of Derales tube and fin types, or look into PermaCool or TransLife, check your local parts stores and see what they carry, find something that has a rating, at least 9-10,000 GVW, too much is OK, not enough is grief .... and make sure whichever way you go to have a trans oil temp gauge

Bill

Lots of common sense in this advise. Just ordered everything I need. Also would have never thought of adding the temp gauge to monitor things before ruining my transmission.
Much appreciated.

From a lot of experience working with the 700R4/4L60 transmissions since they were brand new, let me assure everyone that they need all the cooling they can get! With at least 5 sets of clutches, there's a tremendous amount of heat buildup during even normal operation, and if the OD clutch cycles in and out much the temp goes up dramatically. These transmissions need the original radiator-mounted cooler and an auxiliary cooler in series with it if anything other than routine driving is involved. If you do ANY trailer towing, lock it out of OD! Your gas mileage will improve, and the trans won't roast itself.
Jerry

Jerry,

I think its going to depend on how the converter clutch is wired.
On my 69 C10 you can almost see the trans temp climb if you don't get it up into overdrive while towing. Its because the converter clutch is wired to only lock up in OD. I also have the vacuum switch to unlock the converter at low manifold vacuum (84 chevy p/u style). That causes the trans to heat up quickly if the engine load gets high, even in OD.

regards,
Leon

I taught the GM repair course on the 700R4 for several years. There are actually 4 different shift strategies involved:

1. Direct drive (3rd. gear) converter clutch unlocked
2. Direct drive converter locked
3. OD (4th. gear) converter unlocked
4. OD converter locked

The converter clutch is a 1-plate disc inside the torque converter with a friction surface about 1" wide. It is ONLY intended for light-load situations to eliminate the 10% slip built into all converters. Any low-vacuum conditions should immediately disengage the converter clutch to prevent the fuel system from going into "power" mode and destroying gas mileage, and avoiding internal damage to the converter clutch.

Attempting to use the OD while trailer towing results in repeated engagement/disengagement of the overdrive, with resulting overheating as the OD cycles in and out of engagement.

BTW, there's nothing new about lockup converters. The 1949 Studebaker had one on their automatic transmission, and the 55 Packard Ultramatic also had that feature.
Jerry