[truckdude]

I overfilled my chevy TH400 tranmission by about 2 quarts. drove about 8 miles with no problems( truck had been rebuild from the ground up and I got excited about getting the darn thing running and overfilled it somehow) anyways after checking it again i siphoned out the correct amount and know tranny won't engage,(vaccum line is hooked-up) Could i have blown my seals so fast? Also after my tranny got rebuild it sat for about 2 yrs with no fluid in it before my truck was ready for. could this have caused some damaged?

[DoubleVision]

if it sat for 2 years I`d say the seals were already hard. Overfilling it didn`t help matters any due to the higher pressure, In fact, that maybe the only reason it worked when it did, overfilling it created enough pressure for it to overcome the leaky seals. I recently stripped and rebuilt a TH350 that had sat in a shop a long time, the former owner said the same thing "I had it rebuilt 2 years ago by a known shop, I can`t understand what went wrong" when I tore it down the seals were all rock hard and the clutch packs were all cooked. My tech school instructor used to say "if your gonna have a tranny rebuilt and don`t intend on using it for a while, coat the seals in vasaline to keep them moist"