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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1974ChevyC20 on November 15, 2018, 12:11:14 PM

Title: Transmission Trouble
Post by: 1974ChevyC20 on November 15, 2018, 12:11:14 PM
I have a 1974 C20 that doesnít want to move when I first put it in gear. It moves a little and then stops and eventually will move after 5 minutes of revving the engine. I changed the transmission fluid and filter. After it gets moving itís fine. Could it be the torque converter? Thanks! 


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Title: Re: Transmission Trouble
Post by: MIKE S on November 15, 2018, 12:22:49 PM
If your saying it moves and shifts normally when warmed up, more than likely you have hard seals and or sticky valves in valve body. I would try some additive like trans x. Its a seal softener and varnish dissolver. If your saying it always has trouble taking off from a stop then you may have a burnt clutch. Does the fluid smell or look burnt? 
Title: Re: Transmission Trouble
Post by: 1974ChevyC20 on November 15, 2018, 12:36:13 PM
It takes off from stops fine. Itís just when I first start and move it after itís set a day.


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Title: Re: Transmission Trouble
Post by: JohnnyPopper on November 15, 2018, 01:20:19 PM
Sounds like stuck valves, try Seafoam Transmission product. Works good.
Title: Re: Transmission Trouble
Post by: VileZambonie on November 15, 2018, 03:41:04 PM
Are you checking the fluid level with it running at operating temp?
Title: Re: Transmission Trouble
Post by: MIKE S on November 15, 2018, 04:06:46 PM
If when you start it cold and it takes like 10 seconds or so to move and its not slamming into gear once it catches and your fluid level is good then you probably are suffering from converter drain back. In other words as it sets the fluid in the converter is draining down into the pan and it takes 10 seconds or so to pump up the converter. The cause is usually worn bushing in pump and converter drive hub. tear down would be necessary. 
Title: Re: Transmission Trouble
Post by: 1974ChevyC20 on November 16, 2018, 02:27:56 PM
Yes. I am checking it running at operating temperature. It takes a lot longer than 10 seconds to go and keep moving though. It moves about 2 inches as soon as I put it in gear.


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