I picked up my 700r4 from a guy who has been building transmissions for a very long time, he was converting the electric speedo to cable drive, anyway, he asked me what I was using to cool the transmission, and I told him I bought a aluminum radiator with tranny cooler. He said I was way better off not using the radiator cooler and just add a aux cooler, the kinds that just mount in front of the radiator. He said the transmission would practicly last forever if I did that. He told me that the radiator coolers were just short of worthless, and that the aux cooler would cool much better, and also the engine would run a little cooler. I bought the radiator with a cooler, but I am going to take his advise, because one thing I know for sure, and that is, he knows a whole lot more about that stuff then I do. Anybody have any thoughts about this?

I am not an expert but the information below sounds about right, wouldnt hurt to run in series, would be the best of both worlds?


http://www.transmissioncenter.net/competition.htm

(per the above) You must have a transmission cooler in your radiator regardless of what someone has told you for the transmission to last. Auxiliary coolers are just that, in addition to. Water cools better (faster) than air always, period. The transmission fluid comes directly from the torque converter at a much higher temperature than the water in your radiator and is cooled to the water temperature fast. Then it goes to the auxiliary cooler to be cooled far below the water temperature. If you don't need a cooler in your radiator why does GM spend all that money doing so? If you wanted to cool a red hot piece of steel fast would you stick it in water or air, see the point. Your transmission will run cooler with a lock-up converter. This is more important with stall speeds of 2000 RPM or higher.


The most often asked question is should I bypass the radiator cooler when I install a auxillary cooler.
Most cooler manufactures and automobile manufactures information we have read, recommends installing the coolers In-Series with the factory radiator cooler for maxium cooling efficiency.
So unless the manufactures who have spent 1000's of hours testing different installations are wrong, the suggested cooler installation is in-series......
Transmission > Radiator cooler > Auxillary cooler > then Back to the transmission.
If you must bypass the radiator because the cooler tube is leaking or for other reasons, be sure to increase the size cooler you install by 1 to 2 sizes.

I am not an expert but the information below sounds about right, wouldnt hurt to run in series, would be the best of both worlds?


http://www.transmissioncenter.net/competition.htm

(per the above) You must have a transmission cooler in your radiator regardless of what someone has told you for the transmission to last. Auxiliary coolers are just that, in addition to. Water cools better (faster) than air always, period. The transmission fluid comes directly from the torque converter at a much higher temperature than the water in your radiator and is cooled to the water temperature fast. Then it goes to the auxiliary cooler to be cooled far below the water temperature. If you don't need a cooler in your radiator why does GM spend all that money doing so? If you wanted to cool a red hot piece of steel fast would you stick it in water or air, see the point. Your transmission will run cooler with a lock-up converter. This is more important with stall speeds of 2000 RPM or higher.


The most often asked question is should I bypass the radiator cooler when I install a auxillary cooler.
Most cooler manufactures and automobile manufactures information we have read, recommends installing the coolers In-Series with the factory radiator cooler for maxium cooling efficiency.
So unless the manufactures who have spent 1000's of hours testing different installations are wrong, the suggested cooler installation is in-series......
Transmission > Radiator cooler > Auxillary cooler > then Back to the transmission.
If you must bypass the radiator because the cooler tube is leaking or for other reasons, be sure to increase the size cooler you install by 1 to 2 sizes. Thanks for the feedback! That is what I was trying to figure out, and that is, why dont the manufactures just use a aux cooler? And maybe I just misunderstood him as to the fact that I need to run both for long gevity. I have used aux coolers before and had them hooked up as you mentioned, and never thought you could just run the aux cooler without the radiator cooler. I had to have misunderstood what he was saying, and I will run both. I have read that for every 20 degree drop in transmission oil temp doubles the life of the transmission.

I can tell you this. I own a 1-ton Ford van that came stock from the factory
with a seperate tranny cooler mounted in front of the radiator hooked up in
series with the cooler in the radiator. Everything on this van is heavy duty
and it is set up for towing. I currently have 155,000 miles on it and have had
no tranny problems at all.

In addition, I believe the radiator 'cooling' cicuit actually help get the trans up to temp quicker in extremely cold weather.

If the truck is only used for summer driving, this is not a concern, but if it is a year round driver or something that might see use in cold weather, it is something to consider.

If installing a cooler, I would not abandon the radiator cooling circuit, both would work together OK, I imagine.

One of the few things that will broast a 700R4 regardless of cooling, parts, current condition, etc.. is if the t.v. cable is not properly adjusted. Aux coolers, etc... will be a distant consideration if the t.v. cable is not setup right.

Do you have the carb with correct mounting points for the 700R4 tv cable or the kit that effectively mimics the mount?

best-
S-D

Attached below is some text concerning the tv cable from Chevy High Performance:
Automatic Shifting Control

All of GM’s overdrive automatics use a cable connected to the throttle that tells the transmission when to shift. If this cable, called a Throttle Valve Cable (or TV cable for short), is connected incorrectly or misadjusted, the trans will shift too soon, too soft, too late, or not at all. Chevy High Performance outlined proper adjustment techniques for the TV cable back in the Mar. ’99 issue in a story titled “Hard Hittin’ Shiftin’” on page 66. If you’ve installed your overdrive and the trans won’t shift right, read that story and check out your adjustment. Holley, TCI, ACT, and GM all offer cable attachment brackets to facilitate TV cable connections to any carb. Also, there is no vacuum modulator used on the TH700/TH200, so you can plug the old line that ran from the base of the carb or intake manifold to the transmission.

If you are aware of all this, no problems-- and have fun with the OD.

In addition, I believe the radiator 'cooling' cicuit actually help get the trans up to temp quicker in extremely cold weather.

If the truck is only used for summer driving, this is not a concern, but if it is a year round driver or something that might see use in cold weather, it is something to consider.

If installing a cooler, I would not abandon the radiator cooling circuit, both would work together OK, I imagine.

One of the few things that will broast a 700R4 regardless of cooling, parts, current condition, etc.. is if the t.v. cable is not properly adjusted. Aux coolers, etc... will be a distant consideration if the t.v. cable is not setup right.

Do you have the carb with correct mounting points for the 700R4 tv cable or the kit that effectively mimics the mount?

best-
S-D

Attached below is some text concerning the tv cable from Chevy High Performance:
Automatic Shifting Control

All of GM’s overdrive automatics use a cable connected to the throttle that tells the transmission when to shift. If this cable, called a Throttle Valve Cable (or TV cable for short), is connected incorrectly or misadjusted, the trans will shift too soon, too soft, too late, or not at all. Chevy High Performance outlined proper adjustment techniques for the TV cable back in the Mar. ’99 issue in a story titled “Hard Hittin’ Shiftin’” on page 66. If you’ve installed your overdrive and the trans won’t shift right, read that story and check out your adjustment. Holley, TCI, ACT, and GM all offer cable attachment brackets to facilitate TV cable connections to any carb. Also, there is no vacuum modulator used on the TH700/TH200, so you can plug the old line that ran from the base of the carb or intake manifold to the transmission.

If you are aware of all this, no problems-- and have fun with the OD. Thanks for your input, makes perfect sense. I did a lot of research before chosing the 700r4, and the proper tv cable setup was well understood before I went with it, I am using a holley 750 with the holley tv and throotle bracket along with the tv cable correcter on the carb, so I should be in good shape.

My trans guy, who is VERY good has told me that the TV cable is absolutely critical with these transmissions. He also told me that running just a trans cooler is not good. The radiator not only cools the fluid, it also warms it to operable temprature. That makes sense because until you warm the fluid, you are yanking on a cold trans.

the reason for the secondary cooler on an overdrive tranny such as the 700r4 or the 2004r (or newer models) is because when the overdrive is in use, and the torque convertor gets into it's 'locked' position, it apparently generates additional heat (more heat than say a th350/400 in the same situation)...

I've done quite a bit of research on this over the years, and this site is a good starting point http://www.bowtieoverdrives.com