I have a 1999 Ford Ranger. The automatic transmission will not shift into drive when warm unless you put it into one or two first after using reverse. The transmission shops all want to rebuild it. I have had the transmission fluid changed by the local shop. When warm if you just go to drive, it will jerk into gear, similar to sidestepping a clutch. When it is cold it will ease its way in to drive fresh our of the garage from reverse, and you will feel it take a hold. It does not slip when driving, shifts fine, and downshifts when you need it to downshift with throttle response.

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On other forums it was suggested to change a gasket inside the valve body. I had the valve body gasket changed. Could this be a fluid problem cured by some mouse milk additive or a different fluid. It has 150,000 miles on it.

I'm not a auto tranny expert, but your issue sounds like an issue with the valves; they can usually be refurbished for far less than an overhaul including the clutches.

The sign near the drive indicator says

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SHIFT TO 1 BEFORE SHIFTING INTO DRIVE

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This has been the best solution for about 3 years now. It is much cheaper than paying REDLICH TRANSMISSIONS $3500 for fixing something that is not broken.
Thanks Rusty for your input.

Rusty, This may have come up before . Would it be a good idea to use synthetic trans fluid in 1970's gm auto trans?

Should be OK - check the backward compatibility claim for "Type A"(which became Dexron). I'd avoid the Dexron/Mercon combo products.

quote:

I'd avoid the Dexron/Mercon combo

Rusty could you please elaborate on your suggestion?

It all relates to "slip-stick differential"(SSD). Type A (GM) had a smooth SSD, that locked up gradually. Type F (Ford) had a an SSD that locked up quickly.

SSD is a measure of how the friction behaves as two sliding surfaces slow to static. GM SSD has less friction as static occurred, so static engagement was smooth. Type F SSD friction increased as static approached, so the lockup was firm.

Over the years, Dexron and Mercon became close in specs.

quote:

Originally posted by Rusty:
It all relates to "slip-stick differential"(SSD). Type A (GM) had a smooth SSD, that locked up gradually. Type F (Ford) had a an SSD that locked up quickly.

SSD is a measure of how the friction behaves as two sliding surfaces slow to static. GM SSD has less friction as static occurred, so static engagement was smooth. Type F SSD friction increased as static approached, so the lockup was firm.

Over the years, Dexron and Mercon became close in specs.

Rusty, Do you think the oil combination would be any contributing factor to my sticking valve. I do not know what was put in the Ranger transmission but, I will ask the mechanic the next time I get in for service.

The fluid formulation would have little to do with the sticky valve, although it might be some sludge or varnish, not specific to the blend.