jhawkthebeast

Hey what’s up guys. I recently drove my 72 cutlass from Dallas to okc ( I was scared shitless) I made it all the way to the border and my trans started like downshifting and what not so I exited right at the red river and let it cool down cuz I checked the fluid it was all good and full. I got gas then got back on the road. Then it started doing the same after 30 mins of driving. It’s a new tci I we put on just before I left for college. Basically I had to stop every 30-45 mins because the trans would overheat and downshift. I’m just wondering if I should get a trans cooler since it only happens when I’m driving on 3rd gear for an extended period of time. If so can u guys recommend which type and which brand. If not let me know what I should do.

oldcutlass

First see if the kick down cable is adjusted right or sticking.

Fun71

I have never heard of a TH350 downshifting due to excessive heat.

Vintage Chief

No. You already have a transmission cooler at the bottom of your radiator which is nominally designed to cool your ATF. You do not need nor do you want to add a separate dedicated transmission cooler. You only need to resolve the issue you are having.

70W-32

Did you install a highew stall converter with the new trans?

Vintage Chief

I make no apologies - are you sure you're transmission is "overhearing"? I'd like to hear what it heard.

Fun71

Agreed that there is already a trans cooler and an external may not be needed. Minor technical point, the trans cooler is on the right (passenger) side of the radiator and not the bottom. You can see it if you look in the filler neck on a radiator that's empty or has very low coolant level.

Vintage Chief

Oh yea....my bad.....on the RH side. I have my 2003 F250 6L diesel on my brain (the trans cooler is on the bottom). I need to change out the ICP valve on that bloody thing ASAP. Argh.

Fun71

I hear ya about so many vehicles you lose track of which one has what. The trans cooler on the replacement radiator that I just installed in my Jeep Wrangler is on the bottom as well (even though it has a manual trans - universal part to fit all applications). The main reason why the trans cooler location on the Cutlass is burned into my brain is mine leaked after getting the radiator rebuilt and having to bring it back to the radiator shop to have the cooler replaced, so I saw the radiator disassembled with the cooler exposed.

jhawkthebeast

no it’s actually a lot lower then the previous one it’s 2000 rpm stall

oldcutlass

Which is still higher than stock, but that's not your problem.

Vintage Chief

If it was running properly at cruising speed I wouldn't suggest this - because it wouldn't be the transmission vacuum modulator correct? But, since it is not operating correctly at cruising speed, it does lend itself to the possibility the vacuum ATM (automatic transmission modulator) is suspect or a vacuum hose on the TVS assembly? JS

Vintage Chief

Do you have the 1972 CSM? Check out the location of the ATM valve on the transmission - any oil leaking from it? Is the vacuum hose securely attached to the ATM valve? Trace the vacuum hoses on the TVS (DVCS) assembly - ensure they're all securely attached. Ensure the electrical wire harness at the top of the TVS solenoid is secure.

70W-32

If your trans is actually overheating, the trans fluid will smell burnt and be changing color to a dark red/burgandy color instead of the bright red it originally looked like.

Schurkey

You've got a failed transmission.

At best, the filter is plugged. Shutting the engine off allows some of the sediment plugging the filter to fall to the bottom of the pan. Depending on what the sediment is, MAYBE you could replace the filter and be OK. (Not likely. Possible.)

At worst, the filter is plugged because the clutches are coming apart.