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My 91 Reatta convertible exhibits the following symptoms:
At initial start up the car begins to roll out in second gear then shifts to third gear at around 25 mph. Unless, while at normal operating temperatures, I depress the accelerator hard at which point the transmission drops into 1st gear. Then shifts to second at around 20 mph and to third at around 33 mph.
Fourth gear is only attained when the car is cruising at above 48 mph or greater and I accelerate hard (placing the engine under heavy load and reducing manifold pressure). At which time the transmission shift up in to 4th gear. If throttle pressure is kept constant or released the transmission drops back into 3rd gear, rpm’s increase and speed remains constant.
When test driven with the vacuum modulator disconnected and the vacuum line plugged the transmission works properly.
The modulator was examined and verified to be the correct part for the car although it is an aftermarket part.
Under heavy acceleration, when the transmission finds its way into the proper gear the power brake light illuminates. The light goes out a few seconds after the engine load is reduced.
The car had been stored in a heated garage for about 5 years due to an engine failure. The engine was rebuilt and reinstalled.
The transmission pan has been dropped and no significant material was found. The throttle position sensor has been replaced. A reputable auto electric shop has tested the solenoids and they were found to be working. The solenoids were tested by a transmission specialist at a local GM dealership and found to be “questionable”. The GM dealership has estimated a cost of $950 to replace the three solenoids. The solenoids cost $25 each the remainder of the cost is for labor and supplies.
Before I invest $950 in the dealership what other options can you suggest?
1. Can the Solenoids in the transmission be tested with out dropping the transmission for $900 dollars?
2. What other causes are there for this strange behavior?
Thanks for your assistance.
Rhr_entrepot – Tulsa Oklahoma
At initial start up the car begins to roll out in second gear then shifts to third gear at around 25 mph. Unless, while at normal operating temperatures, I depress the accelerator hard at which point the transmission drops into 1st gear. Then shifts to second at around 20 mph and to third at around 33 mph.
Fourth gear is only attained when the car is cruising at above 48 mph or greater and I accelerate hard (placing the engine under heavy load and reducing manifold pressure). At which time the transmission shift up in to 4th gear. If throttle pressure is kept constant or released the transmission drops back into 3rd gear, rpm’s increase and speed remains constant.
When test driven with the vacuum modulator disconnected and the vacuum line plugged the transmission works properly.
The modulator was examined and verified to be the correct part for the car although it is an aftermarket part.
Under heavy acceleration, when the transmission finds its way into the proper gear the power brake light illuminates. The light goes out a few seconds after the engine load is reduced.
The car had been stored in a heated garage for about 5 years due to an engine failure. The engine was rebuilt and reinstalled.
The transmission pan has been dropped and no significant material was found. The throttle position sensor has been replaced. A reputable auto electric shop has tested the solenoids and they were found to be working. The solenoids were tested by a transmission specialist at a local GM dealership and found to be “questionable”. The GM dealership has estimated a cost of $950 to replace the three solenoids. The solenoids cost $25 each the remainder of the cost is for labor and supplies.
Before I invest $950 in the dealership what other options can you suggest?
1. Can the Solenoids in the transmission be tested with out dropping the transmission for $900 dollars?
2. What other causes are there for this strange behavior?
Thanks for your assistance.
Rhr_entrepot – Tulsa Oklahoma
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