Transmission Oil Cooler

[Kilian]

Was the only factory remote transmission oil cooler offered on square bodies the one in the radiator tank or was there an option for a remote cooler in front of the radiator (similar to the remote engine oil cooler)? I've seen mention of the V02 trans oil cooler rpo code...is that just the radiator cooler that seems pretty common?

 

[75gmck25]

AFAIK there was a factory remote transmission cooler option that mounted up in front of the radiator, but I’ve never seen one from the factory. Aftermarket dealer-installed coolers were very common, and were installed inline with the cooler in the radiator.

I have also seen the remote engine oil cooler option, which connected lines to the base of the oil filter adapter, and they ran up to a small cooler in the front.

 

[Bextreme04]

A factory external cooler was definitely offered. The trans cooler was on the passenger side and the engine oil cooler on the passenger side. It was far more common on the 454 and diesel trucks, especially with a trailering package.

 

[Kilian]

Thanks. Do either of you or anyone else know how these external transmission coolers were plumbed to go along with the radiator tranny cooler? Did the lines go to the radiator first and then to the external cooler in front of the radiator?

 

[Matt69olds]

Any cooler is better than no cooler, regardless of the lines are connected.

If you drive in a climate where it gets cold, run the fluid thru the auxiliary cooler first. That way there is little chance of over-cooling the trans. That’s also not a bad idea if the truck tends to run hot, cooling the fluid before it gets to the radiator means less heat the cooling system has to contend with.

If your really working the truck hard, then cooling the fluid after it leaves the radiator might be helpful.

You might also consider a deep pan. A couple extra quarts of fluid is always good. You didn’t mention what transmission you have, but factory 400 deep pans are easy and cheap to use.

 

[CalSgt]

My dad retrofitted an external cooler from a '98 K1500 without too much difficulty. Our engine trans donor truck was a 98 with a 4L60E

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[shiftpro]

They also had an engine oil cooler too, which was super cool. I have one on a parts truck here, maybe a 78 k20 BB, TH400 and that crappy transfer case that doesn't have 2wd.. well anyway it has a pretty cool factory oil cooler!

 

[75gmck25]

Plumbing it in before or after the factory trans cooler is often debated, but the order is unlikely to be critical. Transmission oil temperature in these older transmissions is not very critical until it gets really hot. However, some folks like to plumb it so they get the radiator heat to warm the fluid in cold weather before it’s routed back to the transmission . Mount the cooler with metal brackets, not the plastic ties that push through the radiator. You want it to be solid, and to not scrape against the radiator.

I highly recommend using a stacked plate cooler, not a tube and fin cooler. If you are in a cold climate you should consider something like the Long Mfg. low pressure drop (LPD) cooler, which has a thermal bypass built in to route fluid around the cooler until it is warmed up. They are reasonably priced, and there are models rated up to about 28k GVW.