Transmission shudder on a 1992 XLT.

[jsrealestate]

I have a 1992 Explorer with 217,000 miles. My auto transmission is shuttering at 1500 to 1800 RPM when cruising on the highway at 55 mph while in OD. The shutter is especially bad when it is raining or very damp weather. I thought it was an ignition problem since I had the transmission fluid changed at 214,000 miles. So I replaced the spark plugs and wires. Still had the shutter, but it was better. I cleaned the throttle body and the air bypass valve. I tried cleaning the air bypass valve, but I was only able to spray throttle body cleaner inside the two ports and blow shop air into it. The inside still seemed to have crud on it. The cleaning helped a lot. However, the shutter has abated, but it is still there. Before I spend the $90 bucks on a air bypass valve, I would like confirmation that I am on the right track. Comments are much appreciated

 

[BrooklynBay]

Welcome to this forum! I've moved your thread to the transmission section. Is your fluid bright red or somewhere in between? Try some Lubegard additive. This chart is in # 34 in my list of useful threads:

 

[jsrealestate]

Air Bypass Valve

The fluid is bright red and was recently changed. I took the bypass valve off and cleaned it for the second time. The explorer now has 218,500 miles and the shutter is gone.

 

[BrooklynBay]

Thanks for the update!