Flush or Replace OEM transmission cooler

The new radiator was not ran with old transmission. I am rebuilding the engine, and doing a few transmission mods, and don't know history of front cooler, so I was just trying to find out if it is worth flushing, or not. I purchased the M7B cooler. The radiator cooler, and the new M7B cooler, should be plenty sufficient. I don't plan on towing anything but maybe a utility trailer every now and then. I appreciate all the help and knowledge!

CHEVYS4ME said:

That's my next question... I have replaced radiator already with an aluminum 3 row. The trans lines go into radiator trans cooler, and out to front mounted trans cooler, then back to trans. Should I just bypass radiator trans cooler, and just use the new front mounted one only? I am going to get the M7B cooler.

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Don't replace the cooler, flush it. Buy 2-3 cans of Supertech engine degreaser and 2-3 more of Supertech brake cleaner and shoot the degreaser through the cooler and lines first, then the brake cleaner for the final wash. Lots cheaper. I have airless paint sprayers and just pump lacquer thinner through everything.

Do NOT bypass the auxiliary cooler. It is a heat exchanger that both warms the fluid on cold start (think of line pressure when it's 0 degrees outside) and cools when things are getting hot in the summer and running hard.

The penny pinching factory did not go to the significant expense of designing, manufacturing and installing radiators with heat exchangers in them just for the hell of it.........

Hook up both coolers and lines to the trans but, don't hook up the lines to it. Then get a couple cans of this stuff (or similar) and spray it in both directions until it come out clean. Then blow out the lines with compressed air. Next hook the lines up to the trans and fill it.

CHEVYS4ME said:

The new radiator was not ran with old transmission.

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Ah OK I was thinking it had been. My mistake. Yeah in that case I would replace the AUX cooler with the M7B (mainly just as an excuse to gain some cooling capacity over the OEM one), install the new radiator, and call it a day. You'd probably be fine with a flush as others have pointed out but the M7B is cheap insurance and a nice upgrade.

df2x4 said:

Ah OK I was thinking it had been. My mistake. Yeah in that case I would replace the AUX cooler with the M7B (mainly just as an excuse to gain some cooling capacity over the OEM one), install the new radiator, and call it a day. You'd probably be fine with a flush as others have pointed out but the M7B is cheap insurance and a nice upgrade.

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I agree. M7B purchased...

I had just replaced my transmission when the torque converter went bad and found shavings in the pan. Flushed it a couple cans of transmission flush. Two years later, no issues. I’m not saying it will work for you, but I didn’t want to spend the extra dollars.

Don’t forget about the Transmission lines, flush or replace all three lines, Do not reuse the flexible rubber hose. As for the cooler in my opinion sometimes the original OEM part if in good condition are better than aftermarket parts.

Burb99 said:

As for the cooler in my opinion sometimes the original OEM part if in good condition are better than aftermarket parts.

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The TruCool M7B is literally exactly the same as the OEM AUX cooler except larger. It's even made by the same company, Long Mfg.

CHEVYS4ME said:

Just trying to figure out if I can safely flush my oem auto trans cooler? I can remove it, flush it, use compressed air to clean out solvent, etc... But want to know if it is recommended? I know some say just replace it. I have a brand new GM remanufactured 700R4 in my 92 c1500 now, but trans before this, and right before I bought it went out. Now I just tore up the front crank thrust bearing, apparently from too much pressure on torque converter pushing against crankshaft and pushing crankshaft forward with pressure wearing out bearing. I'd rather clean it out if it is ok.

Waiting to hear what the experts around here have to say

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New trans costs what $15-2200? A cooler costs about $60/80 bucks?
I wouldn’t reuse a cooler. It’s not worth it imo.
If you flat out have to....install a inline transmission fluid filter.

Does the M7B have the low pressure drop feature?