Hmmm...I found this "The THM200 and the THM250 have pans shaped like a THM350, HOWEVER, the THM200 will have the words HYDRAMATIC DIV. and METRIC stamped into the pan."
at this site http://www.nastyz28.com/chevy-transmiss ... cation.php
'89 Astro, 4.3L, TBI. Minor intake and exhaust mods. Rebuilt 700R4 trans (by me). Corvette servo, 0.5" boost valve, police grade 1-2 accumulator spring (shifts fast and solid). B&M stacked plate trans cooler. Bilstein shocks. Belltech sway bars front and back. New head unit, speakers and subwoofer. Needs paint and a new headliner.
name's Steve
I can't remember all I've forgotten about that....
That THM250 may have been a better choice for your mini truck, as the trans body is much smaller in diameter, and would fit in the trans tunnel with less modification. Strength won't be an issue, as these trannies came behind 305 and 265 chevy V8's, as well as the 200 and 229 V6. You don't need the super low 1st gear of the 700R in a light weight mini, but you would have to count the shift detent stops on the linkage to see whether it is an overdrive unit or not.
Same basic transmission that was installed in the Buick Turbo Coupe, and the successor, the Grand National. Hardly a weak design in my book.
Marrying a chevy/spicer shaft to your Mazda shaft will be quite easy. Mazda has a flat flange, and spicer and neapco make 1310 U-joint flanges. Beat one of the flanges off of your Mazda driveshaft, and take it with you to your local driveline shop. If they can't find a perfect match, the holes can be drilled in the axle flange to match. Be sure that the snout that centers the shaft flange to the diff flange is perfect. If need be you can buzz the diff flange off, and have a machine shop open/match the pair before installation.
The driveshaft will hold up fine. I would hold off on chopping the Mazda end off of the shaft. Most likely it will have to be shortened, and you can simply buy a weld yoke that fits your driveshaft tube. Being Mazda and Ford shared that truck platform, chances are good that it will have 2 inch tubing, which is very available. Then your toughest problem would be pounding in a new u-joint.
yep, there are a whole bunch of what the industry refer to as "bastard" joints, with one size on one side of the cross, and another size on the other. I have joints in my Suzuki Samurai that are 1310 spicer on one side, and Toyota Land Cruiser on the other. You should be in luck.
Make sure your buddy has driveline experience. Improper phasing of the ujoints will cause vibrations like no other. Phasing is the alignment of the yoke placement. Look at your shaft as it is, you will see that the U-joint yokes are all installed in the same direction, to cancel out harmonics of turning in a concentric circle. Pretty darn close is good enough, because a degree or two will not affect things. If its just welded on wherever, you will have nothing but trouble. If you need more of an explanation, I have a buddy that put together a video on phasing, so you can see what I mean. Let me know if you need to see it.
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