Does My Truck Have An External Tranny Cooler?

bdbwtie · July 24, 2011

Hi, I am new here! I own a 97 chevy 1500 z71. This truck has a 16ft landscape trailer on the hitch about 90 percent of the time. I just had the transmission rebuilt as the old one was shot with 158k on it. I just installed a temp guage in the pressure point so i have an idea what is going on now. It currently runs about 150-160 around town empty. I have yet to pull with the guage installed so i dont know what it will do then. Ive been looking into external coolers and running it in series with the raidaitor cooler. Im receiving conflicting reports as too if i have one already?? ive tried following the lines but get lost in the mess without tearing stuff apart. So does anyone know if i would have one from the factory?? if so should i be looking at an aftermarket or what are your opinions?? Just dont wanna risk buring up an expensive tranny again!! Thanks in adance!!

8.1HD/ALLISON · July 24, 2011

You should be able to follow the lines to the front. If the truck has an external cooler, it will be in front of the ac condensor. It should be roughly 1/4 to 1/2 the size of the condensor. If you got 158,000 out of the last tranny and pulled a trailer that much, I wouldn't worry too much. I would make dang sure whoever put the new tranny in flushed and checked the flow rate of the cooler system and lines. Hate to burn a new tranny up cause a 100 dollar cooler is clogged.

bdbwtie · July 24, 2011

You should be able to follow the lines to the front. If the truck has an external cooler, it will be in front of the ac condensor. It should be roughly 1/4 to 1/2 the size of the condensor. If you got 158,000 out of the last tranny and pulled a trailer that much, I wouldn't worry too much. I would make dang sure whoever put the new tranny in flushed and checked the flow rate of the cooler system and lines. Hate to burn a new tranny up cause a 100 dollar cooler is clogged.

i tried following them but loose them underneath the bottom raidiator line. i do have another cooler in front of the a/c condensor but im not sure whats it for. one tranny line does look like it continues under the raidaitor towards the grill though, but i cant see any lines off of the small cooler as its at the bottom of the grill. I know when they built the tranny they did flush it good and it has a warranty so i would think they made sure it was right.

I bought the truck with 78k on it and have been pulling a trailer since roughly 120k so it hasnt had alot of trailer pulling. the old tranny did get kicked into limp mode atleast 2 times prior to it going. And heat is what eventually took it out. (over heated, blew out tcase seal and pumped tranny fluid out vent) tq convertor wasnt fully locking up. Just want to avoid this issue. The tranny is built for pulling now, just want to makes sure everything else is too.

txab · July 25, 2011

Look through your grill and see if you have something like this in front of your condenser. May be 1/2 the size of the one pictured.

wavery · July 25, 2011

If the guy built the trans for towing, I'm fairly certain that he would have sold you a trans cooler if you don't have one......at least I hope he would have....

One thing that I found helpful on mine is a pusher fan for the cooler. It makes a big difference. Especially in stop & go traffic on a hot day:

bdbwtie · July 25, 2011

Look through your grill and see if you have something like this in front of your condenser. May be 1/2 the size of the one pictured.

Yes i do have something about half that size in front of the condensor. Would be bottom left of grill while looking head on. Guess i while have to tear it apart to find out forsure as i have to replace the raidiator anyways. On that note, what would you guys recommend? running through the internal cooler and external or by passing the internal and going to a big external or possibly two externals?

wavery · July 26, 2011

Yes i do have something about half that size in front of the condensor. Would be bottom left of grill while looking head on. Guess i while have to tear it apart to find out forsure as i have to replace the raidiator anyways. On that note, what would you guys recommend? running through the internal cooler and external or by passing the internal and going to a big external or possibly two externals?

Run it through the internal cooler and external.

The external cooler is not nearly as efficient as the internal cooler. However, the fact that the fluid going through the internal cooler is not as hot (because of the external cooler) it takes stress off of the radiator which helps cool the engine at the same time. The whole system works together.

The pusher fan also helps the radiator and A/C condenser to be more efficient.

If you're going to buy a new radiator, you might want to see if you can find one with an additional row of core.

redvett · July 28, 2011

Look at the RPO codes and see if its got KNP HD trans cooler.

bdbwtie · August 13, 2011

Look at the RPO codes and see if its got KNP HD trans cooler.

What are these RPO codes and were would i find them?? I im thinking about doing a pusher fan, what would be a good recommendation?? Also what do they get wired into as far as a thermostat for engaging?? Im thinking I need to do something as i have seen it slightly over 200. Granted this was loaded with the trailer and over 90 degrees farenheit outside with the ac on blast. But it wasnt stop and go either.