Transmission shifting problems

[C203/4]

I have a 72 3/4 ton pickup, the transmission was fine untill the drive blew the motor up (he never checked the oil) now the crank slaps against the block, like a sledge hammer, but ever since, the transmission, when you put it into drive, stays in first gear, take your foot off the gas, and it wants to shift up a gear but it really doesnt, like it is almost in second gear, but not quite, slipping i guess, what do you all think is the problem?

I have almost completed the rebuilding of the 350 chevy (2bolt) but i would like to trade the 4bolt "elcamino special" that came out of the truck for a transmission anyone near Austin? just dont want to put it all back together with that transmission and have spent the "wifes budget" on the truck already!

[bryanw1968]

Make sure you plugged the vacuum line from the carburetor to the modulator at the tail end of the transmission. With that line unplugged, it will act EXACTLY like that.

Good luck,
B-dub

[Longhorn Man]

Yup, and if it pops off in traffic, or if it is too cold or wet to crawl under, you can drive it like a manaul. (I also use this for quick troubleshooting) Place it in first, drive normal, but rev it a little higher than when it would normally shift on it's own, then pop it in 2nd... ditto with 3rd. If the hose is popped off, or the mod is bad, you'll be able to drive it like this.

[skchevota]

Yes the vacume lin e. now you did not say, was it not shifting properly with the old engine while it was knocking and banging. If that is the case, depending on what let go in here, there might not of been enough manifold vacum left to make it shift right. the only other thing would be if the govener is stuck, it wont upshift ither.