Adding Trans aux cooler need advice

[Dannothemanno]

So im trying to add an oil cooler to my truck since I just got my transmission rebuilt and I was wondering if it would be a great Idea to just bypass the cooler in the radiator or just connect it to it. And what would be a good cooler to add I was planning on adding this one but I'm not sure what all I'd need to do to make it fit

https://www.oregonperformancetransm...1uRqQXfnGDr1yDjAmiPVAuG0qfoNwUZRoCdJ4QAvD_BwE

 

[df2x4]

Personally I would use both the radiator cooler and the AUX cooler. I know some people disconnect the one in the radiator, but it does provide quite a bit of extra cooling capacity at higher temps, and it will help the truck come up to temp sooner. That last part won't matter as much to you being in Texas, but still a good idea IMO.

That Tru-Cool 40K you linked to is a great cooler, but it's huge. You'll be moving the bracket that the horns mount to at the very least. If you want something smaller that will still do a good job check out the Tru-Cool M7B. You can add one of those in the factory AUX cooler spot and even use the factory brackets if you trim them a little. Here's a how-to thread on that.

https://www.gmt400.com/threads/how-to-factory-auxiliary-trans-cooler-upgrade.18104/

And here's a link to the Tru-Cool M7B.

https://www.amazon.com/Tru-Cool-M7B-ENGINE-OIL-COOLER/dp/B003TQ7WDA

 

[Dannothemanno]

Personally I would use both the radiator cooler and the AUX cooler. I know some people disconnect the one in the radiator, but it does provide quite a bit of extra cooling capacity at higher temps, and it will help the truck come up to temp sooner. That last part won't matter as much to you being in Texas, but still a good idea IMO.

That Tru-Cool 40K you linked to is a great cooler, but it's huge. You'll be moving the bracket that the horns mount to at the very least. If you want something smaller that will still do a good job check out the Tru-Cool M7B. You can add one of those in the factory AUX cooler spot and even use the factory brackets if you trim them a little. Here's a how-to thread on that.

https://www.gmt400.com/threads/how-to-factory-auxiliary-trans-cooler-upgrade.18104/

And here's a link to the Tru-Cool M7B.

https://www.amazon.com/Tru-Cool-M7B-ENGINE-OIL-COOLER/dp/B003TQ7WDA

The reason I was wondering if I should bypass the radiators cooler is because the past owner installed a delphi radiator but I don't know how long ago and i hear people say that if the radiator breaks it could cause the coolant to leak in my trans

 

[df2x4]

It can happen. I've personally never seen it but I know some people here have. In my opinion the benefits of using it outweigh the risks, but that's just me.

 

[L31MaxExpress]

The reason I was wondering if I should bypass the radiators cooler is because the past owner installed a delphi radiator but I don't know how long ago and i hear people say that if the radiator breaks it could cause the coolant to leak in my trans

I have seen it time and time again on Nissan midsize SUVs and Trucks but not on GM vehicles. Hot fluid from the trans should enter at the top of the in radiator cooler, the lower fitting should be the outlet into the external cooler, finally the external cooler outlet is the return to the transmission. I ended up adding a thermostat on my Express van to automatically bypass the external cooler when it was not needed. In 40*F weather at highway speeds my trans was only running 120°F.

 

[Dannothemanno]

It can happen. I've personally never seen it but I know some people here have. In my opinion the benefits of using it outweigh the risks, but that's just me.

So I've decided I'm going to bypass the radiator but do you think the cooler you mentioned would have enough cooling power?

 

[df2x4]

So I've decided I'm going to bypass the radiator but do you think the cooler you mentioned would have enough cooling power?

I doubt it. If you're bypassing the radiator cooler I'd stick with the 40K.

 

[L31MaxExpress]

So I've decided I'm going to bypass the radiator but do you think the cooler you mentioned would have enough cooling power?

If you bypass the radiator cooler you will lose cooling capacity. If you run uphill with an unlocked converter it will overheat your trans.

 

[Dannothemanno]

I have seen it time and time again on Nissan midsize SUVs and Trucks but not on GM vehicles. Hot fluid from the trans should enter at the top of the in radiator cooler, the lower fitting should be the outlet into the external cooler, finally the external cooler outlet is the return to the transmission. I ended up adding a thermostat on my Express van to automatically bypass the external cooler when it was not needed. In 40*F weather at highway speeds my trans was only running 120°F.

So should I change the way the lines are set up then

 

[1989GMCSIERRA]

I always completely bypassed the radiator cooler when I install coolers. And I put a inline filter On the cooling system

I use the cooler from a 6.0 Ford on every automatic trans truck I own. My GMC is gonna get one also. I just get the 32 row coolers. I swapped out my 7.3 factory cooler to a 6.0 cooler back in 2004. 180,000 miles on a 4R100 and not one issue. I did replace the TC but other than that no issues.