Hey guys,I was out and about last night and gave a bit of heavy throttle,enough to engage kickdown .......Then all of a sudden very little drive and a lot of rattling!!! so i limped home and took out the transmission today and sure enough the 8 roller sprag has burst out of its cage,is there a upgrade sprag unit I can replace it with?preferably the whole unit as it is damaged...
her is a pic

 

I'd check with TCI. Their stuff is about as HD as it gets for high-perf autos.

www.tciauto.com

 

I assume its the intermediate sprag youre talking about and yes, there is a 34 element style one available. Not only are there more "elements" they are a dog bone style rather than a spring and roller style. Last time I rebuilt a th400 it was because of a sprag failure and I installed a 34 element style.

 

Great to hear I'm not the only one that this happened to,where did you get the replacement parts and what was involved to do it eg;did you have to modify anything?thanks for your help.

 

Got it from the same place I got the rebuild kit from, local supplier called caltrans but shouldnt be a problem getting one, all over the internet. No modification necessary, just drops in place of the factory one.

 

34 element sprag is a must for any T400... hell those can break too... I think there is 36 element sprags out now for them...

Usually you'll pop a sprag when tires are spinning then suddenly "hook up"... Like rolling out of the burn out box at the track and letting the tires screech at the end...

 

That intermediate overrun clutch is very similar to the TH350 - I've broken several of those spring-and-roller types until I installed a Coan 36-element intermediate sprag (which is similar to the TH400 34-element sprag style). No further problems.