I own a 2000 Ford equipped with a 7.3L Powerstroke and 4R100 transmission. The transmission finally needed to be rebuilt, so I took the truck to a reputable shop in western Washington State that specializes in performance diesel engines and transmissions. I was told that this 4R100 was built to handle 450+ hp, which is more than I’ll need. The transmission build included a triple-disc billet torque converter, Transgo Tugger-shift-kit, Banks Transcommand, and a fluid top-off with their recommended synthetic ATF.
Since the transmission rebuild, our family has moved to Seabrook, Texas, where I began a new job. From the first test drive, the transmission has had a busy shifting problem, but I suppose that all the miles driving from the Northwest to Texas has made the busy shifting problem all the more annoying. Around Seattle, I never drove the truck enough for the problem to be as grating. When I accelerate, I can find a combination of speed and throttle position that causes the transmission to constantly search up and down for the best gear. The truck will do this even when using more power and throttle position. I have taken the truck to several shops here in Texas but they can’t find a solution to the problem. I spent nearly $4,000 the first go-around in Washington. I don’t want to do that again.
Jeff Syphurs Seabrook, TX We believe that a big part of the problem in finding a solution is because of the number of non-standard parts and products involved with your particular truck and transmission build. A performance transmission rebuild usually involves modification to the valve body and/or the addition of a shift kit that alters hydraulic clutchapply pressures and sometimes shift scheduling, and a performance billet torque converter can sometimes operate or lock up differently than a stock unit. Also, the Banks Transcommand electronically alters operation in some important ways, though usually for the better. In short, these non-stock variables combine to make it hard for even a well-trained and experienced Ford 4R100 tech to find a solution to a
problem. When someone wants a performance automatic installed in his or her truck, we recommend working with a quality shop that has developed a good reputation over some number of years. Alternately, when buying a package from out of state, we recommend a complete performance transmission package from a reputable vendor who is used to dealing with long-distance customers. They have the experience to know what products or what combination of products will work together to produce the results the customer is looking for. And they have enough technical support on hand, as well as an incentive, to troubleshoot most any problem that might develop. Obviously, the shop that did the primary work would normally be our first choice in helping to solve this problem. If that’s not possible, we’d remove every aftermarket product that alters programming or performance that you or someone else added in an effort to get the transmission and the engine back to a baseline that a shop in Seabrook would be familiar with. Try to get the transmission operating normally with as few non-standard variables as possible. If the transmission cannot be made to operate normally when the truck is brought back to a clean baseline, the problem is definitely internal to the transmission. That said, and before pulling the transmission, we’d ask a qualified Ford-trained 4R100 tech to go for a “ride-along” with a scan tool. There is a wide range of transmission-related functions that can be viewed and analyzed in real time. We’d want to know that the Throttle Position Sensor (TPS) and Engine Speed Sensor (ESS) are relaying the correct throttle position and engine speed information to the vehicle’s Powertrain Control Module (PCM). Shift solenoid function can be monitored, and the scan tool can even be used to select gearing and torque converter lockup manually. There’s a lot to be learned by a ride-along. You didn’t mention any trouble codes, but we suspect there may be one or more. Any codes you discover would help to narrow the possibilities. Good luck.