zman might have meant a plate style cooler as being more efficient than a tube/fin. however, i had a plate style and a transmission pro suggested removing it and replacing with a tube/fin. he said the higher pressure fluid flow of the tube/fin was less likely to get stopped up than the low pressure flow of the plate design.

during you recent desert trip, did you have the AC on? I notice on mine the temps go up a lot when the AC is on and the condenser is working.

someone makes cooler with an attached fan. i've seen it over on the diesel sites.

4lo will run cooler, as things are turning a bit faster at engine and trans with less slippage.

+1 on replumbing it back through the radiator. the radiator will pre-cool down to 200ish and then allow the trans cooler to do its job. chances of radiator failing and mixing the fluids are very very low.

 

I am glad that you posted this thread today because it made me go out and test The Dawg aux trans cooler made by haden ( http://www.haydenauto.com/New%20Prod...g/Content.aspx ). I picked mine up at Pep Boy here locally. It has a 10" fan on a tube and fin and is mounted to the left (drivers side) of the condenser because of the hood latch. I have a switch it the cab that I manually turn it on and off. When diving a mix of highway and city driving with it off the temp is around 150. When 4x4ing with out it on at 15 MPH the trans is at 186. With the fan on it is at 171. The only problem I have now is that my engine temp is nearing 215. I suspect that my thermostat is not opening. I only 4x4 in sand on the National Seashore here in the Corpus Christi, TX area. We have a stretch 60 miles that offers great fishing on the beaches of the Gulf of Mexico. We fish for shark, king mackerel, red fish, speckled trout and various other indigenous salt water fish. I also have a double deep tans pan from mag-hytec. I only use the fan when 4x4ing and never have tested the temps before. I only did this today on my lunch break. I do not have a temp gauge for the trans. I used my digital multimeter that has a temp probe on it. I hope this helps you figure out what you can do to cool the trans down some while 4x4ing. In the sand we can 4x4 up to 35 MPH and at that speed the temp is 160.

 

That is the route I am going to take with a small fan in front of the cooler. I want to get the trans oil temps below 200* if I can. If not well then it was fun killing time!

I didn't have the AC on when I was wheeling as I don't like being cooped up in the cab outdoors. I have noticed that my engine temp has gone down a few degrees after I bypassed the radiator. I need to go back out there and do some steep climbs in 4lo to see how much difference it makes too.
That fan that was suggested actually has a fan shroud depth of 1.25" and the motor adds more giving it a total of 2.50". I found the measurement on another site so I can't use it. I took some more measurements and it looks like with some finessing I can fit this one in there. It has a total depth of 2.05". I think I will put another gauge and sender coming out of the cooler as well to see the comparison. Besides, you can't have enough cool looking switches and gauges.

On my old 95 ZJ with the 46RH I never had any of these problems but they did come with a small aux trans cooler but nothing special. I never had one trans issue with that one and I sold it at 225k miles still running good.

http://pitstopusa.com/i-5082830-spal...r-440-cfm.html

 

I forgot to mention that this was with my A/C on.

 

A number of the Third-Gen F-Body crowd like water wetter for improving efficiency of the cooling system..... some have seen as much as a 15 degree drop in max temps just by adding the stuff to their coolant.

 

I have been thinking about that. I am going to drain some of the coolant and add more distilled and try that water wetter stuff. I assume it's safe for the radiator?

 

That looks interesting. What would be te coolant mix with that route?

 

Just add a bottle to what's in the radiator. That's it. (provided there is room, if there isn't, drain some coolant out.)

 

I looked at the site and am guessing that I should use two bottles for our cooling system size.

 

Our cooling system is less than five gallons. Only need one bottle.