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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Fish on January 15, 2009, 06:45:25 pm

Title: th350 is not shifting??? Help please
Post by: Fish on January 15, 2009, 06:45:25 pm

Hi guys & gals,

I just drove my 86 SB home for the first time since putting the moter and tranny in and it would not shift out of first.  The vaccum is hooked up to the manifold vaccum.  I don't know what the issue is.  Fluid is good.  It is a fresh rebuild, so there should be no issues with the tranny, but there is.  Anyone have any ideas?  Thanks in advance,

Fish

Title: Re: th350 is not shifting??? Help please
Post by: VileZambonie on January 15, 2009, 07:12:18 pm

Is the detent cable hooked up? Is the governor gear ok?

Title: Re: th350 is not shifting??? Help please
Post by: Fish on January 15, 2009, 07:22:26 pm

Yes to both.  The only thing that I think it could be is the connector in the vaccum hose isnt letting enough vaccum get to the tranny, do you think this could be it?

Title: Re: th350 is not shifting??? Help please
Post by: VileZambonie on January 15, 2009, 07:26:40 pm

pull the hose off the modulator with the engine running. Is there vacuum? If the detent cable is adjusted correctly and the governor valve is good you'll have to give more detail on what you did to the transmission.

Title: Re: th350 is not shifting??? Help please
Post by: Jon87V20 on January 15, 2009, 07:34:15 pm

Which port do you have the modulator getting its vacuum from?

Title: Re: th350 is not shifting??? Help please
Post by: Fish on January 15, 2009, 07:35:45 pm

Its getting the vaccum from the manifold

Title: Re: th350 is not shifting??? Help please
Post by: roadrage41 on January 16, 2009, 07:27:08 am

you have a shift kit installed during the rebuild?

Title: Re: th350 is not shifting??? Help please
Post by: Fish on January 18, 2009, 03:53:18 am

Yes

Title: Re: th350 is not shifting??? Help please
Post by: joesgarage71 on January 18, 2009, 10:44:24 am

Quote from: Fish on January 15, 2009, 06:45:25 pm

It is a fresh rebuild

I'd be takeng it back to the rebuilder.

Title: Re: th350 is not shifting??? Help please
Post by: DnStClr on January 19, 2009, 11:56:51 am

Could it be that the modulator might have to be swapped with a modulator to match the shift kit?

Title: Re: th350 is not shifting??? Help please
Post by: joesgarage71 on January 19, 2009, 01:16:06 pm

Quote from: DnStClr on January 19, 2009, 11:56:51 am

Could it be that the modulator might have to be swapped with a modulator to match the shift kit?

Some are adjustable, sm screw in the vacuum port.