Originally Posted by tkoopen
Hi there Hot Rodders, got a question. I have an 18' Open Road C30-class 1972 motor home with a 350 Chevy engine and it came stock with the TH350 heavy duty?? transmission. My current problems are the high RPM's at cruising speed of 55 miles an hour being approx. 2800 to 3000. I believe it came with 4:11 differential gears that I do not wish to currently drop down for climbing altitudes of 7,500 feet and then having to pull over to let traffic pass as required because then the "poor girl" does her best getting up an rolling again from a near dead stop.
So, given that said I am currently researching to see if I can modify this transmission to a TH350C overdrive type with a locking torque converter which I read was available and part of this transmission application. I have read the postings and felt you could answer this possible modification.
The T-350C is not an over drive transmission. It is the same 3 speed trans as a regular T-350
The T-350C does have a lockup converter design. The fuel mileage benefits would be minimum
You can not converter your T-350 to a T-350C trans