Vannin' Community and Forums Forums Chevy General Discussion 1978 g10 5.7l 350 won’t drive!

I recently got a 78’ Chevy g10 with a 5.7l 350 v8, which someone had for some reason removed the transmission (a turbo 350) and left it sitting in the back of the van. I was told that the van ran great prior to the trans being taken out, and it has fairly low miles at 158k but it had been sitting for more than a few years, not exactly sure how long but a good while. Rats had destroyed the spark plug wires and most of the belts and hoses, and so on, but after a lot of work, I was able to get the transmission back in and driveshaft and so on, cleaned out the rat crap as best I could and with new belts and finally (I think) sorting out the mess of vacuum lines, I got her to fire up quite easily. Now I go to take it on a quick test drive and at first it does drive but really really little power to the wheels. The motor revs up like it is In neutral and just barely starts to get going finally and I get a half a block and make a turn and then it won’t go anymore. Motor still runs, and will rev and rev, but the van just won’t go anywhere. It seems to move a tiny bit easier in reverse but not much. One big concern and this could be the sole cause of this and I’m just not too familiar with transmissions really so I don’t really know but it is still missing the detent cable, whatever ya call that cable. So the hole in the trans where it should go is just open still. Writing this I now am feeling pretty certain that of course this is the problem but I’m just wondering what y’all think. I am by no means a mechanic, but I am a die hard diy’er and when something on my truck breaks; I learn how to fix it by figuring it out and fixing it; in fact I do that with anything not just my truck, and I’m pretty damn good at fixing stuff I guess lol but this whole van project was my first go at a transmission project so I’m still just wingin it haha

Sounds like the transmission is smoked, however it's very important that the detent cable be in place.

That being said I could have sworn the kickdown function on the TH350 and TH400 transmissions was vacuum controlled. Maybe the transmission that was in the back of the van was the wrong one.

How much fluid did you put in the transmission before your test drive? And did you verify the correct level prior to trying to drive it? I thought the detent cable was only needed for it to kick back down into second under heavy acceleration. Like NateB stated, it does sound like the transmission was slipping before you drove it.

The fact the trans was out in the first place should be the first sign that something was wrong with it. Pull the pan and check for glitter/chunks. You're looking at about $1200 to take the trans to a shop for them to rebuild, or $1800+ to limp the van to a shop for them to remove, rebuild, and replace the trans.