Transmission Shifting Hard

[MustangP51]

I have a 00 5.0 AWD. The transmission has been shifting hard for some time now and I have taken it to several garages and they cant figure out what it is. It did this several thousand miles ago and when I had the fluid changed (non synthetic) it worked fine for a long time. Then it started shifting hard again, so I had the fluid changed again, this time with Mobil 1 ATF. Nothing changed, It still shifts as hard as it did before. The weird thing is it will have days where it will shift fine, then the next it slams through the gears.

I know the fluid was changed to, that was the first thing I checked.

 

[BronxBroncsFan]

Throw in a bottle of Lucas' Transmission Fluid. This could help and would be a cheap fix. It would make the existing fluid thicker, and if your Trans. is old this will help. Says right on the bottle 'eliminates hard shifting'. I throw in a bottle on every car I owned.

 

[BrooklynBay]

Do you have any codes or a flashing overdrive light?

 

[MustangP51]

No codes and no flashing O/D

 

[BrooklynBay]

Does the shifting problem happen when it's cold, hot or under a heavy load from towing? How long does it usually take to appear after you start driving?

 

[MustangP51]

usually if I drive very easy on it it shifts fine, with the exception of a few shifts. It seems that it is the worst when it downshifts when the rpms are low at around 1,300 RPM then ends up at around 2,000 to 3000 RPM, usually going up hills. I think Im going to try to get a video of it tomorrow, but im sure its not going to do it with a camera in the car.