1990 GMC Sierra SL1500. THM400 3-speed. OEM fluid is obsolete, so help me pick something from modern offerings. Current fluid looks nasty gray and gives off slight burnt smell. 133k miles, so could be factory fill...
Couldn't find any info on ATF capacity. Different forums claim 4-8 quarts. Many Corvette guys claim that TH400 shifts better with JD Hy-Gard or UTF. Anyone can confirm or bust this myth? I do plan to install the biggest transmission fluid cooler I can find in near future.
Couldn't find any info on ATF capacity. Different forums claim 4-8 quarts. Many Corvette guys claim that TH400 shifts better with JD Hy-Gard or UTF. Anyone can confirm or bust this myth? I do plan to install the biggest transmission fluid cooler I can find in near future.
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