Transmission Disengaged After Sudden Stops

My 1999 Mercury Tracer has 86,000 miles on it and the automatic transmission generally works great. Problem I do have is that if a make a sudden hard stop, it seems the transmission disengages. If I shift into various gears to include park and reverse and rev the engine, the transmission will eventually reengage (normally while I am in 1st gear) and I can then proceed on my way. Other folks who have driven the Tracer say that the transmission seems a bit slow to engage when you are stopped and shift from reverse to drive or vice versa. I also do notice just a bit of slipping sometimes when starting off from a dead stop. Any ideas what might be likely causes?

Low fluid would be the first thing to come to mind. Since you didn’t confirm it, I can see it sloshing away from the pickup at a hard stop …pause a while until the pump starts seeing fluid again …and off you go. Same thing with the REVERSE to DRIVE. Inertia of the fluid in a low level state.

This is often a symptom of a low transmission fluid level. Have you checked the level? If it is low, then you have a leak that needs to be found and fixed.
When was the fluid last changed?
If you have let this go on for a long time (it sounds like you have), then it is very likely that you have done considerable transmission damage and may have to rebuild or replace it.

Why do I find myself in the middle of the next episode of “Scare Tactics”? (sighs, pinches bridge of nose and shakes head slowly).

I did say “very likely”, not “certain.” Maybe I should have just said “likely.”

Obviously, the OP should start by checking the level and bringing it up to the correct amount. After that, he may find that he is very lucky and not have any serious problems for years.

Conversely, I am convinced that if the OP goes to a chain transmission shop, they will tell him he needs a new transmission no matter what.

Sorry! Forgot to mention fluid level is good. In fact we changed the fluid thinking it may be problem (fluid was darkening). After replacing fluid and filter, transmission shifts smoother than before but I can still disengage transmission with a sudden stop.

Sorry! Sorry! I do not believe I EVER drove the car with low transmission fluid and fluid was always the same, full level when I checked it.

Transmission fluid was always good when I checked it.

Find a good, local transmission shop and have it scanned for codes - there are transmission codes that can be present without turning on the check engine light, and a typical OBD II scanner won’t do it. (Or is the check engine light on?)

If you come up with some codes, post the exact codes here.