70cutlass350

Hey ya'll. I was driving my cutlass today, the first real time this year. and this winter i put a tci 2500 stall converter in my th350 trans. i was wondering what is the temp supposed to be. i was running at 60 mph about 2200-2300 rpm with a temp of 190-195 about. the rear diff is a posi 2.73 gear. i do have a external trans cooler. it is like brand new fluid. the trans was rebuilt winter of 2011.

any input would be great! thanks

oldcutlass

What temp is your thermostat?

TripDeuces

http://www.tciauto.com/tc/trans-life-expectancy

Direct from TCI

ah64pilot

Was your trans temp 190-195? If so I'd say you're good to go according to what Trip posted.

I think the normal trans temps are about 230? if you're just using the radiator cooler. If you have an aftermarket cooler I would imagine you will see quite a bit lower temps.

70cutlass350

like my engine temp? it is just under 210

70cutlass350

yeah my temp was 190-195, that is right in the middle of that chart.

someone told me that trans missions should not go over either 230 or 250. and that they run at about 170 or so. but that was for newer cars. so i just thought i better see what a th350 was supposed to run at. thanks!

oldcutlass

Are you using the radiator and a trans cooler? Btw, on your engine temp, I would try and get that a bit lower during cruise.

70cutlass350

would using a 185 degree thermostat bring it down? yes i am using both rad and external.

oldcutlass

Yes it would it would if your running a 195*. I would run a 180*, which in turn should bring your trans temp down about 10*.

70cutlass350

okay i will change that out and post what it reads after that. thanks ya'll

TripDeuces

I would use the external only, bypass the one in the radiator

70cutlass350

why just the external?

TripDeuces

TCI and others don't recommend the radiator one because they feel it just adds heat. If you're trying to keep your transmission at 175* then running it through a hot radiator just defeats the purpose. If you look at that chart going from 175* to 195* reduces the life of the transmission by half, that is substantial for only a 25* increase.

http://www.cpgnation.com/forum/tci-t...faqs-2095.html

70cutlass350

okay, put the 180* thermostat in, the engine now runs at 190-195. i disconnected the trans cooler in the radiator, so it is running Only on the external one. and it was running at 180, then after some more aggressive driving it went to 210-220 and stayed there for the rest of the drive(about 9 miles) I didn't like that....i have the temp sensor spliced into the lower (inlet) line that would go into the lower hook up in the rad. is that a good place to have it? or is there a better place to hook it up to that would be better?

ah64pilot

The problem with reading the temp at the inlet is that the fluid passes the hottest part of the car through a steel tube before being cooled...the exhaust. I would imagine that it would give you a higher temp reading than if you took it at the outlet of the cooler or inlet of the transmission. Does that seem right?

oldcutlass

I'm not positive, but I believe the lower line is the output side, the upper is the return. So the temp will be higher there. The return line ought to be cooler.

70cutlass350

yeah, that kinda makes senses. but were would be a better place to hook it up?

ah64pilot

I would think that the most accurate reading would be taken at the transmission. If the fittings are the same, and you have room...I would connect the sending unit at the transmission. If you take the outlet temp at the transmission it will give you the hottest reading (that the transmission sees, before it's heated again by the exhaust) and if you take it at the inlet temp it will give you the coolest reading (that the transmission sees after the fluid is cooled and then passes the exhaust).

70cutlass350

okay. i will have to lift the car up and see how much room i have. i am running flowtech headers so there is not a lot of room there... are you running headers on your car? are you running a auto? if so where do you have yours?

TripDeuces

If your cooler isn't doing the job there are always bigger ones. Personally, I would use the biggest one I could fit in front of the radiator. I see you live in Minnesota. If you drive the Cutlass in the winter that may be a concern. You don't want the trans fluid turning into jelly, it has to flow.

brown7373

I'm not sure what temp my transmission is running, but I recently made some changes on my 72 350/350thm. I have had a brand new 4 core radiator I bought years ago and never installed. In addition, I added the heavy duty Hayden fan clutch (2747) someone on this site suggested. I had it out last Sunday with the top up and the A/C running. It was almost pegged at 180 for the 45 minute drive. When I was stopped and it idled for about 5 minutes it went up to almost 185. A little more roar at low speeds from the tighter clutch but the 180 thermostat opened and it stabilized and never moved.

70cutlass350

the car is not really driven in the winter. as soon as it snows and they put salt down the car gets stored untill spring.

I think i will try hooking up at the outlet on the tanny and see what kinda of temp i'm getting there.

oldcutlass

Can you put the gauge at the exit of your aftermarket cooler or where the line goes back into the trans? You can "T" off that area and its easy to get to.

70cutlass350

But wouldn't i want to know what the temp of the fluid coming out of the trans is? and not what the already cooled fluid is.

oldcutlass

I guess your probably right, you would want to see the highest temp as the fluid leaves the trans. My initial thought was to see if the cooler was actually doing it's job. You seem more interested in what temp your running at.

70cutlass350

Well i was just think that is how it should be hooked up. but that is a good idea seeing if it is working i could hook the gauge up to the return line and see. abot how much should it cool? like a 20* difference or a lot more?

TripDeuces

Also look into a stacked plate design cooler rather than the tube and fin type. Stacked ones work much better.

70cutlass350

okay, sorry it took so long to get back on here. my internet got zapped in a lightning storm we had.
i put the 180* thermostat in the engine so it runs at 190* i was just running the external cooler for a while but on a long drive she would get up to 210. so i am running both the rad and external coolers now, and it will run 175-185. I may look into getting a stack type cooler later on, but for now i like where it is running at.

Thanks for all you help!!

_Luke_