Thank you for the info. It is a th400 built by Hughes to see abuse. Lucus oil sure shift fluid. I don't think that I am getting an accurate temp reading in line. Was lazy and didn't want to pull pan and put sender in. At the time I purchased radiator I was not thinking of the auto trans. Will probably get one with cooler soon.
CK5
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Trans temp?
- Thread starter dangerdog
- Start date
Thank you for the info. It is a th400 built by Hughes to see abuse. Lucus oil sure shift fluid. I don't think that I am getting an accurate temp reading in line. Was lazy and didn't want to pull pan and put sender in. At the time I purchased radiator I was not thinking of the auto trans. Will probably get one with cooler soon.
If your temp sender is in the "out" line from the transmission to the cooler is the hottest fluid you can have, that's where I like to have the probe. From that point it all has to be cooler fluid since it has all the heat exchangers and fluid coolers to go through yet. Pan temps give you an idea on what the fluid temp is prior to going into the system, temps on the out going line tell you how hot the fluid is after the system. I've wondered about the delta between the two temps often.
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I’ve seen 220 coming from the out line at the same time as 175 in the pan. Pan was indicated from ecu.
Yes the probe is in the out line. So maybe it is not as far off as I think.
red EOD
1/2 ton status
Plumbed liquid-liquid cooler first or liquid-air cooler first?
red EOD
1/2 ton status
Have a few hard 90 degree turns, pinched hoses, or a blockage in the hoses?
Coolant temp, and is the engine fan clutch actually working?
Also how are you using the truck, heavy tow rig?
Coolant temp, and is the engine fan clutch actually working?
Also how are you using the truck, heavy tow rig?
Might have missed it when skimming over the multiple pages of replies, but there is one thing I did not see mentioned regarding the trans fluid cooler built into the engine radiator. I don't believe the trans fluid cooling capacity is limited by the engine temperature, meaning if you have a 190 F t-stat and the engine is running at that temperature that does not mean the trans fluid can never be cooled below 190. Rather you should be using the temperature of the ambient air running through the radiator as the temperature delta when considering how much heat can be removed from the trans fluid. I can tell you that if the heat sink for the trans cooler was truly 190 F then that is not a very efficient cooler at all and the trans would likely overheat.
There are no cooling fins for the trans cooler in the radiator. It is surrounded by coolant only. It's basically a small tank within the passenger side radiator tank.
red EOD
1/2 ton status
Fan CFM?
Engine operating temp?
High stall torque converter or a slipping trans will also build heat fast.
Would have to look and see what the cfm is. Big fan covers most of radiator. Engine temp 180- 215. Converter b&m 18-2200 stall. Tra ns not slipping. Brand new Hughes performance
I understand that, but still don't think that the engine coolant temperature is the sole governing factor in the trans fluid heat dissipation. Or maybe it's just that the engine coolant is a good bit cooler in that location of the radiator than the engine operating temperature. Let's say the trans fluid ran the same temp as the engine, but that would say the in radiator trans cooler was 100% efficient and I'm pretty that is not the case. Of course maybe I'm just over thinking this.......
I can't recall what the drop across the radiator is supposed to be, I want to say its around 20*? So maybe ~170*.
This kind of burns a hole in the idea of a thermostat to slow flow to increase cooling. Output of the trans is not governed via temp, and is cycled through at a high rate of speed.
In any case, it's pretty typical for folks to install an auxiliary cooler, obviously the factory setup is not able to keep up under certain conditions.
This kind of burns a hole in the idea of a thermostat to slow flow to increase cooling. Output of the trans is not governed via temp, and is cycled through at a high rate of speed.
In any case, it's pretty typical for folks to install an auxiliary cooler, obviously the factory setup is not able to keep up under certain conditions.
red EOD
1/2 ton status
Overthinking it. With liquid-liquid coolers the fluid that is inside the smaller diameter tubes only has surface contact with the fluid in the main body. No way for air to make contact with the smaller tube because it's fully surrounded by the fluid that's in the main body. So if the coolant is 180F then given enough time (theory) it can cool the trans oil down to 180F. The outside air has surface area contact with the main body, cooling it (antifreeze in this case). Cooling capability of a liquid-liquid cooler is always limited by the temperature of the fluid in the main body.
With the engine temps going from 180-215F, a single electric fan, good sized/plumbed lines, then I'd suspect airflow issues across the radiator/coolers. Could just be dirt, or not enough CFM from the fan.
