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Transmission fluid temps

1989 Dodge B250 camper van hitop with 318 engine, and I think it’s an A727 transmission. Not sure if it has a trans cooler. Bought it last year and am in the process of fixing it up and learning its quirks. It has a transmission fluid temp gauge, and I’m wondering what the “normal” temp ranges are. I’ve noticed temps in the 180-190 range last summer. Today, on a long (90 minute) highway drive, at 60 mph, with an outside temp of around 45, the max gauge reading near the end of the trip was about 145 deg.

I guess my question boils down to: what is the temp at which I should start to worry? Is the 180-190 range normal/acceptable for summer driving?

You can’t look at what the tranny temp runs at, but instead what the engine coolant temp runs at. If there’s no separate tranny cooler then the tranny fluid will only get as cool as the engine coolant because the tranny cooler is in the radiator. So on a hot summer day the tranny fluid temp could get as high as 240-250 degrees. Which is not good for tranny fluid life.

I would install a separate tranny cooler so the coolant temp doesn’t effect the tranny fluid temp.


Dodge Vans don’t come with transmission fluid temperature gauges…Since yours has one, I expect it will also have a separate, aftermarket, transmission cooler…Is the Van equipped with a trailer hitch? A former owner might have set it up for towing…

Normally, there is transmission intercooler contained in the radiator…In this setup, the transmission fluid temperature will parallel the engine coolant temperature…By using a separate transmission cooler, a big cooling load is removed from the radiator and overheating problems are reduced or eliminated… In vehicles with no separate transmission cooler, you can expect the transmission temperature to be in the 180-190 degree range…

Caddyman, this is a Traveler XL camper conversion, so I believe the gauge package (trans temp, vacuum, and rpm) was installed by the conversion company. Does not have a trailer hitch.

You said that you would expect a separate cooler installed with the gauges…but that the 180-190 degree readings are consistent with NOT having a separate cooler…so I’m guessing there’s no separate cooler, but I can look underneath…

Tester, sounds like you’re saying 240-250 is the worry zone…fortunately I don’t think I’ve broken 200 yet…

Thanks, guys.

Here is my WAG, The transmission fluid cooler is next to the radiator. Radiator temps range typically form 180 deg to 210. I would guess that would be a normal operating range for trans fluid.

“Today, on a long (90 minute) highway drive, at 60 mph, with an outside temp of around 45, the max gauge reading near the end of the trip was about 145 deg.”

To me, this says transmission cooler…If it exists, it will be mounted in front of the A/C condenser, or below it, but in front of the radiator.

Follow the tubes out of the tranny, they’ll either go into a tank on the radiator or into a separate radiator. Worth knowing for sure.

OK, will check tomorrow and post results.

Sons grand prix had extra gauges. Trans temp too. Trans are weak links on supercharged gp’s. I drove it in city traffic once and I noticed 205f approx on gauge. This was basically sitting at stop light. Thought that was pretty warm for casual driving.

Caddyman, your first post was correct…trans cooler lines go into/out of radiator…so no separate cooler.

Thanks for all the help, gentlemen.

You are getting the same temp reading I got on my 1997 Chevy 1500 4x4 pickup. I installed a trans temp gage on it. It also had a trans cooler installed. It sill ran thru the radiator cooler also.

180 to 190 is perfectly normal. Worry about it when it gets up to 240+.

Some tranny coolers are set up that way…In that case, the heat exchanger inside the radiator becomes a transmission fluid WARMER in the winter time…

I need help :0 I have a 2001 Ford Taurus which I just got from my dad. I took it for an oil change and they told me they could not change the oil because my transmission was done, that I should consider getting a new car or a new trans. It’s still kind of running, but when I step on the gas, it like holds back and it smokes sometimes. Should I get a new trans or is there something I can do?
I don’t know anything about cars !

Mary, you’ll get better visibility for your question if you start your own topic. Click the “Ask a Question” button at the top right corner of the page and retype your question with an appropriate heading. Otherwise your question is buried at the bottom of this thread that I started with a different question.