4L80 Transmission Temporarily Overheating

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Westieterrier

OBS Enthusiast
Joined
Oct 17, 2021
Messages
58
Reaction score
91
Location
Portland, OR
HWB, they are trucks donated to the Western Antique Airplane and Automotive Museum (WAAAM) in Hood River, where I volunteer several times a month. Some of these trucks may be taken inside eventually and made to run, others may just sit. We have alot of vehicles. I give people rides in old cars and teach a Model T driving class as well. If you are ever in Oregon, you should swing by for Second Saturday (of every month). I am so grateful to have access and interaction with all these great old cars, and people. I took a flight in a 1921 Curtiss Airplane, which will be my last. Not too keen on the old airplanes . . . P
 

mr_josh

OBS Enthusiast
Joined
Mar 12, 2020
Messages
79
Reaction score
147
Location
Oregon
Hey! I have been to the WAAAM several times, lots of fun.

Several GMT400s with truck campers on this site, here's mine in eastern Minnesota this past summer. This is a few weeks after we drove up 97 through the Gorge when it was 116 degrees. The transmission got plenty warm on that one.

You must be registered for see images attach
 

Schurkey

Supporting Member
Supporting Member
Joined
Jan 14, 2018
Messages
10,963
Reaction score
13,741
Location
The Seasonally Frozen Wastelands
3rd with the torque converter locked is better than OD with the converter unlocked. Unlocking the converter clutch leads to heating the fluid.

The engine and trans are working good now. A trans fluid flush and new filter is probably a good idea. But that's just part of getting the "usual" maintenance issues dealt with. At the mileage you have, and the heavy use it'll get, I'd replace EVERY fluid and filter in the vehicle--axle lube, PS fluid, coolant and hoses.

And I'd consider replacing the PS hoses, oil-cooler hoses (if used) and assure that the accessory serpentine belt and tensioner/pulley are in good condition.

And with that load on a regular basis, take an inventory of the trans cooler(s), PS cooler, engine oil cooler because unlike many folks, you might actually need that stuff.
 
Top