Dear Mike,

I have a '66 Chevy II with a 477 c.i. big block and a turbo 400 transmission with a brake. The problem I'm having is that it broke the bellhousing where the top four bolts attach. The car has a front motor plate with the solid motor mounts still being used and a rubber trans mount. I do not understand why it would crack the bellhousing like that. The drive shaft has about 1 inch of movement before it bottoms out on the tail shaft of the trans.

Some other people told me that if the bellhousing bolts aren't tight enough it would cause this, but I did not find them loose.

Thank you for your time. Any suggestions will be appreciated.

Tom

Dear Tom,

The TH 400 O.E.M. case is only thin cast aluminum. We don't know where your particular case has been ­ possibly in a one-ton work truck for 200,000 miles. It may have already been fractured. The standard 400 bell is thin aluminum.

Other possibilities for you might be a 475 factory case, which has a thicker bell. Or you might get an Ultra Bell replacement bellhousing for your TH 400.

It sounds like the trans is correctly mounted; you may just have a bad case. Chassis flex can also come into play by making the transmission case a loaded member. Good frame connectors can help by making the frame more rigid.

Mike Stewart

Mike Stewart is owner of Mike’s Transmission in Lancaster, California. He will answer your questions about automatic or powerglide transmissions. Email: Mike@racingnetsource.com

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