The_Head

OK, I have an autometer trans temp gauge and a mag hytec DD transmission pan. Total fluid volume is like 11 quarts now, I think. The probe is in the place provided by mag hytec.

When driving around normally the guage almost never registers (range is 100-250) sometimes it might touch 125. When I did some towing (6000-7000 lb camper trailer) it got up to 150 and would spike to 180 when I would stop.

I was just curious to know if these numbers sound ok to you guys... kinda worries me that the temps are so low when not towing.

unixcowboy

The temp you're reading IS cooler than the fluid in the internals.

The 'out' line is the best place to read the temp because it is coming directly from the internals, and I remember hearing that it actually come from the TC itself - but don't quote me on THAT - and not mixing with the fluid in the pan - which has cooled some due to air flowing around the pan.

I don't know if anyone has compared the two temps but drive the truck for a while making a few blasts through the gears. Stop and feel the difference between the line that has the sensor in it and the return line from the front of the engine......You'll feel the difference.

What you're measuring where your probe is now is the return temp mixed with fluid in the pan.

I just read what I said and it seems somewhat foggy.....But I've been that way for a while.
Did I make any sense ?

The_Head

I think I understand what you mean. Basically my probe is not in the best place.

unixcowboy

Better than nothing...

The_Head

If you could provide a picture of where it should go that would be cool.

I'm going to be out of town soon, so I will be leaving my truck at the local Diesel shop to get a fuel pressure gauge put in. I might as well have them relocate the transmission temp probe while it's there.

unixcowboy

Since you already have it in the pan, you could leave it....

I found this note on Cummins Diesel Forum :

"If you put it in the pan you don't want to see over 200 degrees. You would have to be towing real heavy to even see that.

If you go into the converter out line you don't want to see over 275 or so."

From one of the trans guru's there.

Also from this forum "....not over 225* in the pan."

And I found this :
"I put a brass tee into the factory sender spot and then put the factory sender on one end and the autometer sender on the other."

Should give you something to think over.

The_Head

Thanks for the help. I will just leave it there.

Firstgenfanatic

I just installed my new Isspro Trans temp gauge yesterday. The probe location is in the factory temp sensor boss (for overdrive). I went on a test run and hit the steepest hill in town........ saw a max temp of 160 degrees.

tcs 91

i have the same setup. i see about 150 driving around. goes right up from ambient when i start it up in the morning though. cools down when it should. i would agree on about 2oo or 210 . that seems like enough for that much fluid and the sensor in the pan. if the temp is floating around there's something amiss. my ga is the digital one, don't have the model handy.

The_Head

You have a first gen?

1985cucv

ive heard of this before. As long as the thing shifts good and firm i wouldn't worry about it. i think fluid is suppose to be around the 160-190 region

archer39

does not appear so. anyway...

i have a deep pan and have my sensor mounted in the pan. When towing my camper (6500gvw) i will easily hit 210. when driving around town i will see between 150-200. in the summer its normally around 180-200. winter, so far has been around 150-175.

Ace

A question to ask about the trans temp along with "what" it's doing, depending on "where" the sensor's located is "when(?)" it's doing it. There's always going to be some variation in temperature throughout the system. The key point is knowing your highest average temp over time while it's working. That means under load in the summer after at least an hour or more, steady state. That's where if you get too high, fluid and seals start getting degraded or damaged.

The pan's a good place to see that average temp over time. The case/body and trans internals all converge on a closely average temperature over time while running (or sitting parked in the garage, for that matter. The torque converter is always going to tbe the hot spot while running, with the lowest and highest temps will normally be at the cooler outlet/inlet respectively, but will track with a steady average over time.

Ideally, a properly functioning cooling system be it water, oil, air-to-air, whatever, would be able hold a steady state temperature under max load conditions basically indefinitely. But it's not a perfect world we live in. The max allowable temp depends on several factors, not the least of which is the coolant, in this case trans fluid. Synthetic fluids will better withstand higher temps for longer periods.

I don't think the technology was good enough to get this stuff totally right when these trucks were designed, so we have make a few adjustments to get the most out of them.