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Classic/Antique Car Repair/1977 GMC 4x4 th350 tranny

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Expert: - 2/3/2008


Question
when i 1st start the truck, it will run in all gears, when it gets warm/hot i only have low and reverse gears, im thinking torque converter,

Answer
It has been my experience that the torque converter has very little effect on the shift points of a transmission or whether it will or will not shift. It sound like the warming up of the transmission might be effecting a transmission valve body valve, the governor, or softening a seal in one of the pistons. But the problem sounds internal.
Brad

Classic/Antique Car Repair

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Brad Sears

Expertise

All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.

Experience

Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Publications
Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

Education/Credentials
More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

Awards and Honors
Moto Award winner. And much more.

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