I HAVE A 2000 EX, 7.3 , 4r100 transmission. This past weekend Saturday at Las Vegas the ambient temperature was 118 deg. I noticed the trans temperature was at 200 deg, While at the stop light waiting for the light to change I put the trans in neutral to hopefully cool it down. As soon a I did that the engine revved up and came back down, it seemed like the transmission torque converter was locked while I had my foot on the brake. The shifting got worse and when it shifted up the engine was revving before the gear changes were late and also the transmission shift was harsh (hard) . The shifting feel was like this all the way home to San Diego. This morning the transmission was cool, drove it to work the shifting was fine and the transmission temp did not even reach 160 deg ( this is the normal day to day temp for the transmission). I was told by the Ford service rep that the transmission fluid temperature is allowed up to 230 deg, but if this is the way the transmission will act with this temperature then it is not good.
For the main question, I was told the transmission cooler for the 6.0 enginge is much larger than the 7.3 and is better and will cool better than the stock cooler. If I swap the cooler to the 6.0 there will be no modification of the mounting nor the modification of the fluid lines. Can anyone verify or make comment about this before I spend the money?

 

It is about the same for mounting. You are going to have to change the fluid lines. Just make yourself an adapter to change it from 3/8 to 1/2 in line

 

You are not talking about any radical temperatures so it should not be what's affecting the shifting. I think you should service the trans, drop the pan for inspection.

 

Same thing happened to me while towing a large travel trailer during summer heat. I thought the tranny was toasted. Got home, next morning the cooled off tranny was fine. I dropped the pan, changed the filter and fluid anyway. Six months later still no problem. I read somewhere on this site that the tranny goes into somewhat of a "limp" mode when they get too hot. I am also interested in increasing the size of the tranny cooler and possibly installing an additional external filter. Does anyone know of a good combo package available. Thanks everyone !!!

 

I don't have my trans gauge in yet but I have read many great things about the UltraCool "CoolMax" setup on FTE. I got mine from Dieselsite who has it for $130. Its a real easy install and it shouldn't take more than 2 hrs taking your time. Here is a pic of it in my truck: