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Doug, ASE Certified Technician
Category: Car
Satisfied Customers: 8604
Experience:  16 years automotive and OTR repair including specialized training from Toyota and Mitsubishi
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1994 xj 40 85,000 miles, just had full engine service, and

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1994 xj 40 85,000 miles, just had full engine service, and autu box fluid and filter changed, the auto box had no problems previously and was, still is very positive, changes up and down at the correct speed, however, when cold, at maneuver and engine idle, it seems to try to select forward and reverse at the same tim and stalls the engine, this happens 3/4 or even 5 times, but when hot the problem does not exist and the car runs normally at all speeds, any ideas.
Hi Keith,

Given the symptoms and the recent work, it appears that you have either a fluid level issue or perhaps some debris loosened during the fluid change.

The description of "forward and reverse at the same time" is what is normally described when the torque converter is locked up. When it is locked up it gives a 1:1 ratio between the crank shaft and transmission, and since you are sitting still, foot on the brake and transmission input shaft locked due to the resistance of the brake and the weight of the vehicle against the tires on the ground etc. Placing the shifter into gear stalls the engine since the immobile input shaft draws the engine rotation to a halt.

While not the most elegant procedure, you can verify this further by clearing a path in front of you when the problem is present, starting the engine and revving it high (3k+), then with only enough brake applied to move the shifter, pull it down into gear. The increased engine RPM should be enough to overcome the 1:1 lock up and you will take off quickly rather than stall.

Because the problem is temperature sensitive I would be most suspicious of the fluid level before anything else.... the fluid expands when hot, so if it only happens when cold this would make sense as well as coincide with the recent maintenance. If the fluid level is OK, it might be worth considering flushing out the system and/or pulling the pan and filter again (make sure the filter was seated properly etc) or even valve body for cleaning etc.
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