Getting a Handle on Half a Dozen Speeds
In the 1993 model year GM introduced the T56 six-speed transmission in the F body cars (Camaro/Firebird). The transmission was designed and manufactured by BorgWarner Automotive and was an evolution of the earlier T5 design. Larger and capable of handling more torque and horsepower, this trans became an instant hit with performance enthusiasts, race teams and hot rodders.
EEC-IV and EEC-V Systems – Odd Behavior
EEC-IV and EEC-V systems sometimes may exhibit odd behavior such as erratic shifting, OD or engine light blinking, nonsense or unrelated codes, with no apparent cause.
July 2002 Issue
Issue Summary:
Fluid foaming in the 41TE may be caused by the cooler bypass valve in the case under the pump.
Delayed bang engagement on the Honda Civic HX may be caused by several reasons, one of which is a stretched steel belt slipping in the pulleys.
After replacement of a turbine-speed sensor, Ford/Mazda CD4Es may experience a persistent gear-ratio error.
We also have included a special conversion procedure for Mazda-to-Ford ID
Isuzu NPR/GMC Tiltmaster
The Isuzu NPR Commercial Truck and GMC Forward Tiltmasters use an exhaust-brake system that assists in engine braking during downhill coasting while the trucks are carrying heavy loads. This system is used instead of the familiar Jacobs Vehicle System known as the “Jake Brake.” When the exhaust brake is activated, it restricts the flow of exhaust with a flapper valve in the exhaust pipe similar to that of a heat-riser assembly (see Figure 1). When the flapper valve closes, exhaust pressure increases, causing air intake to decrease. This increased backpressure and slower air intake reduce torque transfer to the geartrain, producing the desired on-demand engine braking needed during downhill coasting with a payload.
Centerline 101
The axis or centerline of an engine is the imaginary line around which the rotating mass revolves. The torque converter also has a centerline. Torque-converter rebuilders will tell you how important it is to maintain this centerline and to keep all surfaces perpendicular to this line. Transmissions also have a centerline. Most technicians learn early on the importance of good bushings and good bushing surfaces. Good bushings and their mating surfaces help to maintain a proper centerline to prevent seal and sealing-ring leaks.
Intermittent No Voltage
When a vehicle has been in failsafe or limp mode, it is important to check for codes to see what has caused this condition. If multiple codes are present, check to see whether there is something in common with each one.
June 2002 Issue
Issue Summary:
This month we cover an interesting situation in 1999 and later Mercury Cougars that can be caused by a defective radio.
Persistent codes for throttle-position and/or vehicle-speed sensor on Nissan Quest/Mercury Villager can be caused by lower engine mounts.
A number of factors can cause a shuttle-shift complaint in RE units behind 5.9-liter diesel engines that cycle in and out of lockup at highway speed.
Solving Some Tough Diagnostic Problems On The New Process 2500, New Venture 535 Transmission
The New Process 2500 transmission, also known as the New Venture 535 transmission. is an aluminum-cased 5-speed, rear-wheel-drive unit introduced by Chrysler in 1987 and produced through 1992. The unit has a top-mounted shifter and a 4-bolt aluminum top cover and was spec’d to use 10W30 motor oil as a lubricant fill. This unit was found in B/AB Ram Van/Ram Wagon, D/AD Ram pickup/Ramcharger/Ram Cab & Chassis, and N/AN Dakota, Dakota Sport/Dakota Convertible. This design has created some noise and shift problems that have been difficult to solve. This article addresses these complaints and what will fix them.
Orbiting Saturn
The problem here is in the assembly of the 1st-clutch drum. At first glance, all four of the piston-return-spring assemblies look identical (see Figure 1). Each caged assembly contains 16 springs and has an average overall height of 1.170 inches. The size and configuration of the spring cage allow for these assemblies to be interchanged among drums.
AX4S/AX4N – No Go/No Charge
With their fingers crossed and the cooler-return line still in the bucket, they start the car up. The cooler line makes a little pop, a spit, some foamy fluid then, lo and behold, a nice clean steady stream of fluid comes out of the line. Mission accomplished. The converter has charge. After the cooler line is re-connected, the trans is topped off, road tested and everything works perfectly. End of story you say. Not quite yet. The question that remains is what did we do to correct whatever was wrong with the unit? We did not find anything to point a finger at as to the cause of the problem.
May 2002 Issue
Issue Summary:
Harsh reverse engagement in Volvo AW50-42LE can have four possible causes.
Chrysler RWD units may experience repeated failures from meltdown of the front quick-disconnect line clips. Replace the quick-disconnect fittings with threaded fittings that will not melt.
Revisions have been made to the valve body and spacer plate on Ford AODE/4R70W.
Transmission-fluid leak from the vent in a 4T65-E can be prevented by replacing the upper-channel-plate cover gasket with an updated gasket.
A stator support turned inside the cover of a ZF-5HP-18 in a BMW can cause no power on take-off, neutralizing, bind-ups and failsafe.
Check for a defective mass-air-flow sensor in AX4S/N, AODE/4R70W and E4OD with converter-clutch shuttle.
It’s a Tight Squeeze
I could only imagine the thoughts that ran through the minds of R&R men after they lifted the hood to view the Cadillac North Star/4T80-E combo for the first time. Perhaps it was something to the effect of, “Where is the transmission?”
