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View Full Version : Transmission maintenance: synthetic or standard trans oil?



coxfmly
07-21-2012, 11:17
Hello,
I’m planning a summer road trip and need to have my transmission serviced. I’m thinking about going with synthetic but I’m not sure if it’s worth the cost or might be an issue with an older high mile transmission. Also, some shops drop the pan and others tap into the cooler lines to change all of the fluid from the torque converter, which is best? Should I adjust the trans in any way to help when towing?
While towing my trailer (5500 lbs) on flat roads should I be concerned with running in overdrive? In drive I can pull most hills at 10 psi without a concern. I notice that on flat roads the truck likes to run between 63-68 mph. At lower speed (mid 50’s) it starts to bog down and the egts rise. When I slow down, I downshift to keep things happy until I can speed up a bit. My 94 currently has 219K miles.

Thanks…

rustyk
07-21-2012, 22:03
I had my 4L80E transmission rebuilt and beefed up at Suncoast Converters, Ft.Walton Beach, FL, 2 years ago. Webb Transmissions did the removal and reinstall. (I was the first customer after Webb sold Suncoast). Anyway, the question arose, and Webb said if I intended to ever change the fluid again, the synthetic was unnecessary. He did say the the Mag-Hytech pan I already had was a worthwhile investment.

At cruise (60-65 mph) on 95° days, tranny temp runs around 145°, and that's shoving an 8T motorhome with about 100 sq.ft of frontal area.