One of the more popular Ford transmissions these days is the Torshift. It’s a solid, dependable unit that’s been around for a while, making it one that you’re likely to see in your shop.
As dependable as it is, there are a couple problems that have become fairly common on the Torqshift:
- Delayed engagements
In this article, we’ll look at these two conditions. In each case, there are a few different possibilities that can cause a similar problem. Here’s how to isolate that different conditions and pinpoint the exact source of the problem.
Torqshift transmissions can have delayed engagements in forward or reverse gears. We’ll start with delayed forward engagements:
Delayed Forward Engagement — Since there are no solenoids involved in applying the forward clutch, a delayed forward apply is almost always caused by low line pressure. Several conditions can cause low line pressure. The two most common are:
- A worn or defective PCA/line pressure control solenoid.
- A worn manual valve (figure 1).
A faulty PCA/pressure control solenoid can be one of the main causes for low line pressure.
The PCA solenoid (figure 2) provides boost oil to the pressure regulator valve. Without that boost oil, the pressure regulator valve will only regulate pressure to about 11-15 PSI. This line rise circuit requires a strong flow of boost oil at all times.
Another place for these transmissions to lose line pressure and cause delayed engagements is the manual valve, which tends to wear.
Checking for a Worn Manual Valve
You can use a “wet test” to check the manual valve for wear with the transmission still assembled and in the vehicle:
- Drop the pan and the filter.
- Block the filter intake hole (a mop handle works great for this).
- Blow air into the mainline pressure tap.
Watch for excess fluid leaking from the front and back of the manual valve (figure 3). A large leak indicated a worn manual valve. Replacing the valve may correct the problem.
Delayed Reverse Engagement — Delayed reverse is different than a delayed forward engagement. In reverse, the coast clutch solenoid provides apply pressure; all other solenoids prevent flow in reverse.
But the coast clutch only applies in reverse as a back up for the overdrive sprag. If this solenoid isn’t working, the transmission will still have reverse: The sprag will hold and drive the geartrain (figure 4).
Bindups occur when one or more applying components (bands, clutches, one-way clutches) apply in the wrong gear. Bindups can be caused by electrical, mechanical, or hydraulic issues.
Electrical — A bindup can be caused electrically when a solenoid is commanded on incorrectly or powered up at the wrong time. This is often due to a wiring problem.
Use a scan tool to monitor the solenoid commands. Shoot a movie of the event and scroll through the frames as the bind up occurs. If the solenoids are being commanded incorrectly, the most likely cause is a computer failure (figure 5).
Another problem can occur if wiring harness gets too close to the exhaust, causing the wires to melt together. That can be a tough one to find; even an ohmmeter may indicate proper resistance with the wires melted together.
In a perfect world, the computer would set an electrical code, giving you somewhere to look. But, when the wires melt together, the may not happen. In that case, you’ll need to perform a visual inspection of the wiring harness and its related connections to find the problem (figure 6).
Hydraulic — To check for a hydraulic problem causing a bind in reverse, shut the engine off and see if the vehicle rolls back and forth freely. If the vehicle rolls freely in both directions with the engine off, you’re dealing with a hydraulic problem.
Unfortunately, there’s really no way to test solenoid flow without a very expensive machine. So you’ll need to start with something more basic: Visually inspect the solenoids for sticking valves.
If the valves look good and the transmission still had a hydraulic bind in reverse, the easiest test is to switch the overdrive (SSPC-B) LP/LA solenoid with the torque converter clutch (TCC) LP/LA solenoid. If the overdrive solenoid is faulty the bind will be gone, but the engine may die because the faulty solenoid is now applying converter clutch too soon (figure 7).
Intermittent Bind in Drive — This one is a bit less likely, because more than one solenoid will have to allow fluid to flow to create this condition.
If the bind is intermittent, watch the solenoid commands. If the signals are correct, replace the overdrive (SSPC-B) LP/LA and the coast clutch (SSPC-C) HP/LA solenoids (figure 8). They’re most likely sticking occasionally, applying two clutches at the same time.
The Torqshift is a common unit, and it’s one that doesn’t have a lot of problems. But when problems do show up, a clear understanding of the situation and a directed diagnostic approach is the best way to make sure you continue to have fun the transmissions.