Incontinent Coupe
Q. I have a '40 Ford coupe 350/350 SBC/Turbo. In the November SRM there was a question from the person with the '49 Merc and C6 with shifting and leaking problems. I have a similar issue with my 350 transmission, and although it shifts wonderfully, I have a puddle of fluid on the floor if I let it sit for two weeks. Driving once a week is no problem and I never see a drop. Transmission places tell me the torque converter is draining back into the body and filling it so it drops fluid. It has been rebuilt recently (4,000 miles).
Am I having the same problem as the Merc fellow? What gives?Dale SchicketanzVia the Internet
A. To get an answer to your problem, Dale, we passed your letter along to Zack Farah at Gear Star Transmissions. Here's what he had to say:
Dale's situation is in fact caused by the torque converter draining back through the pump and input shaft and overfilling the case, creating a higher fluid level than normal. When this happens, the fluid level goes higher than the selector shaft seal, TV cable boot, filler tube O-ring, and pan gasket. In extreme overfill cases, sending the ATF will be above the pump's O-ring,
Unlike the previous reader with C6 morning sickness, it shouldn't leak in the case of a 350 , even when overfilled, unless one or more of the mentioned components have been compromised. The transmission builder could have improperly installed the selector shaft seal, may have cut the pump O-ring, or it could be as simple as retightening the pan bolts, especially if a cork gasket is used. It can also be an installation error where the filler tube O-ring or TV cable O-ring may have been damaged. In some very isolated cases, the speedometer cable housing may be the culprit.
To find the leak, dry the transmission completely with non-flammable brake cleaner, then use compressed air and a blowgun to dry it off, watching those areas mentioned for signs of leakage. Once found, it's a matter of replacing the seal or gasket that is causing the problem.
Gettin' Pumped
Q.I recently installed an electric fuel pump on my car. After reading your recent story on relays, I decided to include one while I was at it. Should I use a circuit breaker or a fuse in the wire to the pump?Daniel HoytLouisville, KY
A. We generally use fuses on electric fuel pumps just because the pump won't come back on if there is a problem (we also like to use a separate switch so the pump can be shut off independently of the ignition switch). However, to get a second opinion, we asked Dennis Overholser of Painless Performance for his take on the subject.
According to Dennis, racers like a circuit breaker on electric fuel pumps so it will reset and the car can keep going, provided it is not tripped due to a major problem. A fuse is better suited for street applications (particularly when the fuse is in the passenger compartment, where it's easy to get to) because it will not automatically reset. If the fuse blows repeatedly, there is a problem that needs to be addressed. Bottom line: Use a circuit breaker for racing, and use a fuse for the street.
Shifting Options
Q.I was wondering what transmission you would recommend for using behind a Ford Flathead. I am trying to stay old-school but want to drive long distances. I have a '39 tranny but have concerns that it may not be strong enough behind the 150- to 180hp motor I have.
You have written about the cast-iron mid-'60s to '70s four-speed top-loaders using the Jeep shifter and I believe this will work on the three-speed overdrive versions from the same years found in the Granada and some vans, but today the T5s from a late-model Mustang or S-10 seem to be the tranny of choice. Since this is my first Flathead-powered car, I'm not sure which would be the best choice or fit to put into my 1936 Ford coupe.