TH400 3rd gear lockup

[-83MONTESS-]

Today I got the Monte out for the first time this year. I was winding out the gears leaving my driveway and when I hit 3rd gear the rear wheels locked up and the engine revved high like I downshifted and then stalled out. I slipped it in neutral and it started right back up thankfully because I thought I had just seized it up. As I drove home I had no 3rd gear however. It locked long enough to leave 2 20-30ft skid marks! I initially thought I fried 3rd gear but checked the fluid and it looks fine, and all other gears work reverse included which is weird because isnt reverse and 3rd gear failure the most common TH400 problems if there are any? After doing some thinking I began wondering if the shifter cable is just out of adjustment and if so do you think going from 3rd to 1st at about 4-4500rpm is enough to kill a stock 30+ year old TH400? I didnt have time to check the shifter cable because of work but its been on my mind all day. Could I be this lucky? Thanks

 

[lilbowtie]

Had the same thing happen @ the track - thought the rear end had seized. took a new set of slicks to the core. Turned out valve body gasket let go
activating reverse band. A straight edge across the case in this area showed it not to be flat.

 

[-83MONTESS-]

Oh man thats not the kind of pic I wanted to see but oh well. Since the engine is coming out I may as well just rebuild the trans anyway. I guess my next question is there anyone that can refer me a rebuild kit for a trans that will be behind a mild 496 stroker? I priced a few last night on Summit and looked for opinions on google but figured I would try here.

 

[lilbowtie]

I have been using Northern Auto for engine and trans rebuild kits. Their trans kits are Transtar which uses Raybestos clutches and they under $100.00 for a 400.
If you need any hard parts give me a shout I probably have it.

 

[liquidh8]

Had the same thing happen @ the track - thought the rear end had seized. took a new set of slicks to the core. Turned out valve body gasket let go
activating reverse band. A straight edge across the case in this area showed it not to be flat.

Similar issues to my brothers TH400 I was telling you about. The bands and drums were shot, he had no reverse. When you take it out, I couldn't hurt to grab the TH400 book, and pull it apart. No speacial tools are needed.

 

[-83MONTESS-]

Had the same thing happen @ the track - thought the rear end had seized. took a new set of slicks to the core. Turned out valve body gasket let go
activating reverse band. A straight edge across the case in this area showed it not to be flat.

Similar issues to my brothers TH400 I was telling you about. The bands and drums were shot, he had no reverse. When you take it out, I couldn't hurt to grab the TH400 book, and pull it apart. No speacial tools are needed.

Yea im definatley going to buy a good book for it because the last time I rebuilt one the book saved my *ss numerous times. I made the mistake of getting on craigslist and found a decent priced M22 but would still need a clutch, bellhousing, throw out bearing, yadayadayada... I guess I will wait to make a final decision until I pull the 400 out and look at it.

 

[lilbowtie]

How to work with and modify the turbo 400 transmission - by Ron Sessions. I don't think you can get it any more but it will be available at the library.
Great book w/ a lot of mod's your going to want to do.