Haunted Powerglide?

[thelawdoc]

Hello to the Forum. This is my first post after some months of reading through the informative threads here. Alas, I come hat in hand, having recently traded my Harley for a '65-'66 Chevy C10 (Fleetside 250 I6 with 2 speed, automatic, aluminum Powerglide) which is now presenting an issue that has me and my mechanic scratching our heads.

Briefly, here are the facts: Although the truck (and transmission) was running perfectly, I recently noticed drops of transmission fluid from the front and rear seals leaking. I decided it was time for a rebuild. I gave the truck to a shop that has a stellar reputation for working on these trucks and they gave the truck back to me one week later running even better than it had before.

This past Saturday I set out from Brooklyn, New York on my way to vacation in Maine -a 12 hour drive. I was on the interstate about four hours, cruising along at 65 mph, sometimes 70, feeling as good as good can be, and the truck was sounding as happy as I was. Then I stopped to pay a toll. When I accelerated to leave the toll booth, all I got was a revving of the engine. She would not go forward. I tried reverse and she would not reverse, offering the same revving as I got trying to go forward. I tried for a few minutes more, but it was clear that she was going nowhere. A truck gave me a push for a short distance to get me off of the turnpike and into a nearby lot. While I waited for a tow truck, I gave another try and the transmission engaged perfectly, but she would only move about 100 feet and then just rev. In the couple hours that I waited for my tow, I started her up several times and each time the transmission would engage -but only for some several dozen feet of travel forward or backward. Then she would just rev. At no time were there any noises or other clues as to what could be bothering her. Of course I checked the fluid -it was fine. The fluid was perfectly clean and without any burn odor and exactly where it should have been on the stick. I went under the truck and saw that the linkage was not damaged. All lines and hoses appeared just fine to my eye. She was flat-bedded the 200 miles back to my mechanic's shop in Brooklyn where she sat until Monday morning. Monday morning she acted the same for my mechanic as she did for me two days previously.

Around 5pm my mechanic calls me and says I can take my truck. I queried him as to what caused this catastrophic failure of the transmission that he had just rebuilt. He said he honestly did not know. He told me that he dropped the tranny and spent most of the day trying to find something. He found nothing. He says he "hit the books" and consulted with others, but no one had any ideas. He put the tranny back together and into the truck with the intention of sending the truck to another shop. But he started her up and put her into gear, she engaged and drove perfectly! Forward and reverse. He then went out driving and drove for nearly an hour, at all speeds. She performed beautifully. I then took the truck and went driving for about an hour. Everything perfect. Today, I drove her again for an hour. Still perfect.

So I present to this forum the above information in the hope that someone here might be able to tell me what they think the "problem" was. The only idea that I can come up with stems from my mechanic mentioning that he cleaned the valve (pressure valve?). But he says the valve was fine and he cleaned it only as a matter of procedure and did not believe that the valve would have caused the condition that presented itself to us. He insists that he did nothing in the way of any repair. He is scratching his head and I am now too paranoid to get back on the road with the truck for a 12 hour drive up to Maine where my family awaits me. Flatbedding is not cheap, and my nerves get frazzled when I am stranded hundreds of miles from home.

I hope this post is not a ramble. My mechanic is telling me to drive the truck an hour or so each day for a couple more days and, if all remains well, to hit the road. But I am nervous. Unless this forum opines that I go, I am not going. I would appreciate any help that anyone here can offer. Thank you. Alden