73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Rough75C20 on November 04, 2025, 04:56:57 pm
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Hello,
I’m waiting on a transmission to be rebuilt, but can no longer wait as the place I’m storing it needs it moved. I don’t have the transmission and the guy rebuilding it won’t contact me. The guy probably stole it. Either way, I need to figure out how to know what th350 I need. Are there different versions? I have the two piece driveshaft and it is a 2wd long bed with a 305 engine. How do I tell?
Thank you
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TH350 with a 9" tail shaft should have been in there if it was always an automatic.
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TH350 with a 9" tail shaft should have been in there if it was always an automatic.
Awesome. I’ll look for that. Anything else that I need to look for other than the 9 inch tail shaft to make sure it will work with the driveshaft?
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Output shafts are all the same spline in the TH350 and TH350C. A 700R4 swaps in if you move the cross member a little. Attached is measurements
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If you are going to get a new transmission grab an extra gear and go with the 700R4
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My TH350 is on it's last legs. Have considered a 4th gear but have conflicting info on the control cable/system damage if not done correctly.
So much so, that I'm just stuck. Hate it..... :(
Where can I get the straight dope (oxymoron?) on this subject? AI?
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The TV cable just needs to be set correctly. It's not hard to do. If a 700R4 hasn't been updated and you leave it loose or disconnected it's an easy way to kill it fast.
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Thanks VZ.
Is the manifold mounting bracket different?
Recently did a 2.5 lift with Skyjackers.
Rode the 33" till Friday. BFG finally released the 35x12.5.15 and she really looks good. AND a much smoother ride. 8)
I had changed the rear differential from a 3.73 to a 3.41(?) to drop freeway RPM. Probably should go back to OEM if I drop in a 700R, along with taller tires.
Your thoughts?
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I would definitely have kept 3.73's and dropped in a 700R4
The detent cable and TV cable are basically the same thing with a different purpose. The difference is how the transmission uses the input. The detent cable (TH350) basically lets the transmission know driver demand is high and forces a downshift while the TV cable (700R4) operates the Throttle Valve to sense a range of motion of driver demand. The TV valve and Governor valve control upshift and downshift points and the TV valve helps modulate pump pressure. The failure was historically having low line pressure when demand was high due to an out of adjustment TV Cable or disconnected or broken etc. There are several updates to the 700R4 which make them much less failure prone. Nevertheless, the TV cable needs to be properly adjusted.
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Understood, thanks!
My anxiety over this is lessening.
May have asked this prior: is there a year range of production of the 700r that I should focus on? I vaguely recall a certain time where they were not as reliable for some forgotten reason.
Well, it is inevitable, the TH350 will fail. Keeping her clean just to keep her on the road...Reverse has a noticeable lag in engagement.... :'(