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I haven't tried it yet, but someday I'll fit this TH-700R4 4-speed auto to one of my Opels. It's from a Chevy S-10 with the 2.8 V6.

The bellhousing is close enough in overall diameter that it will allow me to mill off about 2" from the front edge and then graft on a piece of bellhousing from a spare 4-speed Opel tranny.

I'll have to have a custom torque converter made, but the local racing tranny shop told me that's no big deal for them to do. I'll use a custom 8" converter which bolts to the Opel flexplate and fits into the TH-700R4 pump spline.

The 'new' tranny is exactly 4" longer than the TH-180. It's a bit thicker in section, and certainly heavier, but the gearing should be awesome. I'll run 3.89's in the rear axle, and with the .70 OD that'll leave me with a 2.72 final drive.
 

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· Super Moderator
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15,243 Posts
Neat idea, and you have the skills and equipment to get it done. Two problems come to mind though, the first is an easy fix with an after market shifter and cable. The other is a little more sticky, you have to run a detent cable on a 700R4 (unless it is modified by the racing tranny shop) or it will melt down in short order.
Thanks for the info Lloyd. I knew I need a new shifter for the extra gear, wasn't aware about the detent cable. And since I will be attempting the overhaul myself (although I haven't rebuilt an auto tranny in 20+ years!), the tranny shop wasn't going to touch anything other than the converter.
 
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