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Discussion Starter #1
Hey all, I'm back again. This time my recently rebuilt TH350 will not shift into 3rd. I did the rebuild myself and on my first discussion post I had issues with it not going into reverse which I was able to fix with all of your comments and advice/tips. I have checked around and found suggestions like replace the vacuum module or check the governor. The vacuum module is new and before installing the governor I checked to make sure it moves freely and gave it a thorough cleaning. What else could it be? Any suggestions out there? I also installed a B&M shifter kit. Thanks
 

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Holds second gear and doesn’t attempt to shift? Or shift to third, but then doesn’t engage third correctly? Your passing gear linkage might not be hooked up correctly.
 

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Discussion Starter #3
Holds second gear and doesn’t attempt to shift? Or shift to third, but then doesn’t engage third correctly? Your passing gear linkage might not be hooked up correctly.
Exactly. Holds second gear and doesn't attempt to shift. So should the detent cable engage at full acceleration or should it be engaging as the accelerator is opening?
 

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For a quick test just drop the downshift cable from the carb and see it it shifts to third. At least you will know if it is an adjustment problem. The cable is for the kickdown to second gear when on a heavy acceleration, or "passing gear"
 

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Discussion Starter #5
For a quick test just drop the downshift cable from the carb and see it it shifts to third. At least you will know if it is an adjustment problem. The cable is for the kickdown to second gear when on a heavy acceleration, or "passing gear"
Thanks for confirming what I thought it was for. That sounds like a quick and accurate test. I'm such a rookie! lol
 

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Hope this helps you find the problem. I run a TH350 in my 66 with a 355 sbc and 871 Weiand blower on the street since 1980 and have had no problems. I don't even have the cable installed and have a manual shift kit in the trans. I figured I dont actually need the passing gear with all the torque I have. Here is a quote from another site.

"Other than the convenience of automatic downshifts into passing gear at highway speeds, there's no real need for a simple kickdown cable on those transmissions like this TH350 that have a vacuum modulator. "
 

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Discussion Starter #7
OK now that I have the transmission issues resolved another pops up. The rear end is humming pretty bad. My question is will any early model GM/Chevy rear end bolt right on without mods as long as it's off a coup/sedan?
 

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A noise that is loud under load, and quiet at the coast mode, probably has a bad carrier bearing on the pinion side. You might be able to fix it with an inexpensive bearing from ORileys?
 

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Discussion Starter #9
A noise that is loud under load, and quiet at the coast mode, probably has a bad carrier bearing on the pinion side. You might be able to fix it with an inexpensive bearing from ORileys?
Can you tell by these pics what year this differential is from? I see a 65 but not sure.
NOVA_1.jpg
NOVA_3.jpg
 

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Sorry, I don’t know anything specifically about gen1 diffs, I was just speaking generally about car differentials. The early Chevy S-10 rearends are fairly narrow, that might be an option?
 

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the ser / model # is on the front of the Pass side axle tube.
take picture of the dif from behind that shows the cover bolts( ten or 12) and housing shape.
 
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