1994 HDJ81 for reference, the original radiator had some crazing so I recently replaced it. As the factory radiator was NLA I went with the recommendation of a few Mud posts and picked up the manual transmission equivalent radiator (PN 16400-17020) which does not have a built in trans cooler. To make up for this I installed a Derale 15830 auxiliary cooler I had lying around.
After getting everything buttoned up I took a test drive around town and am seeing a lot higher transmission temperatures. With the factory radiator/cooler setup temperatures would be pegged around 85C/185F around town and then bump up to a max around 105C/221F after long periods of idling. After peaking it usually took a few minutes of consistent ~50mph driving to get things back down to 85C.
Now with just the Derale cooler temperatures settle in around 95-100C/203-212F in town and max around 120C/248F after long periods of idling. After ~15 minutes of driving at 50 mph temperatures did not drop below 95C/203F. My temperature sensor is right at the hot output line of the transmission itself for reference.
My first question is if this is too hot? I don't like that it's significantly hotter than factory and I'm pretty sure torque converters don't like more than 100C/212F. The transmission warning light has never come on but I've read that trips at a ridiculously high number. Over the summer I spun a bushing on the transmission pump so I'm very paranoid about overheating the transmission and causing more issues.
The only reason I went with the 15830 was that it was a free leftover from a work project but it's only rated for 6,000 BTU/hr. Derale makes other coolers with up to 67,000 BTU/hr of capacity but they cost around $400. What are other people running for auxiliary coolers when they lose the integrated cooler in the radiator? Anybody have transmission temperatures to correlate with their coolers? I have a hunch that not many people have trans temp gauges so they might be running hot without knowing it or causing any immediate issues. I'd like to avoid buying too big or expensive of a cooler so if anybody has recommendations I'm all ears.
After getting everything buttoned up I took a test drive around town and am seeing a lot higher transmission temperatures. With the factory radiator/cooler setup temperatures would be pegged around 85C/185F around town and then bump up to a max around 105C/221F after long periods of idling. After peaking it usually took a few minutes of consistent ~50mph driving to get things back down to 85C.
Now with just the Derale cooler temperatures settle in around 95-100C/203-212F in town and max around 120C/248F after long periods of idling. After ~15 minutes of driving at 50 mph temperatures did not drop below 95C/203F. My temperature sensor is right at the hot output line of the transmission itself for reference.
My first question is if this is too hot? I don't like that it's significantly hotter than factory and I'm pretty sure torque converters don't like more than 100C/212F. The transmission warning light has never come on but I've read that trips at a ridiculously high number. Over the summer I spun a bushing on the transmission pump so I'm very paranoid about overheating the transmission and causing more issues.
The only reason I went with the 15830 was that it was a free leftover from a work project but it's only rated for 6,000 BTU/hr. Derale makes other coolers with up to 67,000 BTU/hr of capacity but they cost around $400. What are other people running for auxiliary coolers when they lose the integrated cooler in the radiator? Anybody have transmission temperatures to correlate with their coolers? I have a hunch that not many people have trans temp gauges so they might be running hot without knowing it or causing any immediate issues. I'd like to avoid buying too big or expensive of a cooler so if anybody has recommendations I'm all ears.
