Reverse Shifts at High RPM Only
 

I have a 2000 Ford Ranger, 3.0 V6, 4x4. It has 140,000+ miles.
The problem I am having is that it will not hardly shift into reverse. To get it to shift there, I have to put it into reverse, then rev the engine up to very high RPMs, hold the break so it doesn't fly backwards, and then it hard shifts into reverse. Also, at times gears 1-3 will hard shift, but if I get into OD my OD light flashes. I recently took it to a transmission shop, to see what they could do to fix it. They changed the gasket on the transmission, because it had a hole in it. I drove it for a week and a half after that and all seemed fine. Then out of the blue, it started doing the same thing. There doesn't seem to be any fluid or anything leaking, and the thought is that it may not be a transmission problem at all, because it still changes gears, and is not completely shot. I've heard some folks say that there is a sensor in the air system somewhere that can cause these issues, but have taken it all apart to see. If anyone has any suggestions, or happens to know a solution, that information would be greatly appreciated.

I doubt it is external.
Automatics work by Pressure, lots of it, the blown internal gasket meant lower pressure.
When you increase RPMs the transmissions main pump can output more pressure.
Repairing the gasket restored the pressure, but my bet is that it has blown again, so they fixed the symptom but not the problem.

No, there would be no leaks if internal gasket goes out.

Unfortunately a rebuild or used trans would be best bet.

You can read here for tips on your 4R44E trans: http://www.sonnax.com/articles/195-T...he-4R44E-5R55E