Ever see what happens when a forward drum in a T-400 explodes. Your lucky to come out of that with both feet attached to your legs. These days we use tranny blankets and shields.
Actually when the sprag broke in my TCI TH400, it just lost 2nd gear. Another guy was driving the car the TCI was in. It broke on the 1st time trial. So I told him to make another pass, and hit the ratchet shifter twice, real fast, and see if it would go from 1st to 3rd. He did, it did, and he won the race. If I remember correctly, the ET only dropped a couple of tenths.
When I asked a local tranny guy about the TCI, he said they probably just used a stock 16 element int sprag. He said all you gotta do is buy a sprag for a Caddy TH400 that came behind a 500 cube engine. Back then, I think most of the big name tranny builders sold these GM sprags, repackaged, with their name on 'em. He was correct. And the caddy sprag fixed the TCI tranny. Worked perfect after that. So, from that time on, the 34 element sprag has been standard equipment in all my TH400's.
One note here, for those who may be considering a TH400. Beginning somewhere around '71 and up, the TH400 no longer had the 16 element sprags, which can be easily replaced with the 34 element sprag. Instead, they had a very weak roller clutch. The later style drums are different and will not accept the earlier type sprags. The entire drum must be replaced with an earlier style, or the drum from a 4L80E trans. Used drum assemblies are for sale on Ebay.
