TH400 rebuild
 

I have a 67 C10 with a 427 and a TH400 transmission. I bought this spring and drove it 1000 miles home, but recently have had issues with it. It sat outside without a hood on it and the truck started to leak transmission fluid. It also did nothing when put into gear, but likely because it's low on fluid. I took it to a local transmission shop recommended by my mechanic, and they pulled the pan off and said that it looked like water had gotten into it and might need a rebuild if the clutches got wet. However, there is no way to tell unless I start to drive it. The transmission is leaking out of just about every seal it can and will need to be pulled and resealed. I was quoted $500 for just a reseal, but there still wouldn't even be a guarantee that the clutches would be ok and haven't gotten wet. The other option is to rebuild it. For a full rebuild he estimated $1000-1200 depending on what needs to be replaced, but likely just soft parts. I think I am leaning towards a rebuild and be done with it, but would I be able to get by with just a reseal? Would rebuilding it add value to the truck? I was thinking about selling it in the nest ~year as well. Are these prices reasonable? Or any other thoughts?

Re: TH400 rebuild
 

I'd be wondering how water got into it. Typically, leaving a hood off won't result in water in the tranny unless one of the follow is going on:

- No tranny dipstick tube - rain water went straight down tube

- No air cleaner assembly on carb - rain water entered carb then leaked down into intake manifold and was pulled into tranny through manifold vacuum connection to modulator valve.

Another way water can enter a tranny is through the vent on the case if the tranny is submerged in water. Water can also be pulled in through poor seals when submerged. The tranny cools quickly when submerged creating a vacuum.

Whatever the source of water, I would highly recommend having it totally rebuilt. I would also keep the TH400.

Re: TH400 rebuild
 

I'm not really sure where the water got in, it had the tranny dipstick in it and the air cleaner on, I even went and put a tarp over everything and it definitely didn't get submerged. I guess that's beside the point now, water got in somehow. I think I was already leaning towards keeping the TH400 and doing the rebuild, I just wasn't wanting to spend that much on a transmission right now. Would his quote of $1000-1200 be fair?

Re: TH400 rebuild
 

I have that quote for my th400. Rebuild it......if u reseal it and it needs more than you spend more money, time and effort.

Re: TH400 rebuild
 

might want to check radiator cooling tank could be ruptured have seen thi happen before.if you didn't live so far away i could build it for you