Hard Shift 1-2 gear

[ima93chevyguy]

Hey guys so my truck is a 93 C1500.

So this has been going on for several years now.
Anyway, when i first bought the truck it did not shift hard, but after several months it started doing it.
So, within a year we replaced the trans with a new one from the factory and it still did the same exact same the same way. It's been doing the hard shift for years now.

Basically its like a laggy shift..? it jerks really hard when it lets go of first and picks up second. It makes my whole dash shake and my flip up head unit almost smack itself. It is completely random when it does it, but usually happens 75% of the time. Weather independent, engine temp independent.. just completely sparatic.

So with all of that, what could it be? I mean it's a new trans (well not new anymore) and it still does the same exact thing it did with the old one. Someone mentioned to me i might want to try another ECM and see if that helps anything.

Any advice or somewhere to start?
Thanks in advance.

 

[Blue 04 Z71]

Had a severe problem with this in a 99 Tahoe. After 2 rebuilt and one used trans we figured it out. It was bad speed sensors. I had my ecm re flashed, new valve body's in the trans's and I added an 1870 eliminator shift kit and none of it worked until I changed the speed sensors.

 

[Oldblue98]

Had a severe problem with this in a 99 Tahoe. After 2 rebuilt and one used trans we figured it out. It was bad speed sensors. I had my ecm re flashed, new valve body's in the trans's and I added an 1870 eliminator shift kit and none of it worked until I changed the speed sensors.

When you say "sensors" are you talking as in which sensors ? Have exact same thing going on and have had it back to transmission shop numerous times it never made a bit of difference ... Got the exact same problem I started with many $$$$ later. It is like it has a harsh shift kit in it and I know it does not. Transmission is rebuilt, torque converter is new, supposedly new solenoids etc etc . The guy had been in business 25 years and I put trust in him. After numerous returns to have the same problem every time, called the transmission shop few days back and number is not in service any longer. Shop out of business !

 

[Blue 04 Z71]

Vehicle speed sensors on the transfer case. The autotrak transfer case had 2 of them. Same part #s. If it's a 2wd I'd assume it would be on the tail shaft of the trans.

You must be registered for see images attach

 

[Oldblue98]

Vehicle speed sensors on the transfer case. The autotrak transfer case had 2 of them. Same part #s. If it's a 2wd I'd assume it would be on the tail shaft of the trans.

You must be registered for see images attach

Ok thanks it is two wheel drive, I have tried everything else , I will roll the dice on this thanks. I thought it was just one on mine but wanted to ask anyways. It is in shop now for upper & lower intake gaskets, soon as I get it home I will give this a go. Compared to the money spent in the transmission, it will piss me off and make me happy at the same time if this is the cure . Thank you very much.

 

[ima93chevyguy]

Thanks guys

Mine is 2wd as well so I'll crawl under it sometime and give a look around and find a part number.
i tried looking it up but i couldn't find anything on a parts website for a 2wd one, they all listed ones that went on the transfer case.

 

[beardeddummy]

It will either be the speed sensor or maf messing up on 96+ trucks

 

[Blue 04 Z71]

The one I posted is for 4wd the 2wd most likely looks different. It might be on the drivers or passenger side rear tailshaft of the trans on a 2wd.

 

[Oldblue98]

Thanks guys

Mine is 2wd as well so I'll crawl under it sometime and give a look around and find a part number.
i tried looking it up but i couldn't find anything on a parts website for a 2wd one, the
I found my part number for the ac delco VSS for m

Thanks guys

Mine is 2wd as well so I'll crawl under it sometime and give a look around and find a part number.
i tried looking it up but i couldn't find anything on a parts website for a 2wd one, they all listed ones that went on the transfer case.

I kind of searched through sites and got a ac delco part # for mine and ordered it and a new connector pig tail on ebay. I know the 93 is more than likely a different number. Good luck with yours

 

[Oldblue98]

Had a severe problem with this in a 99 Tahoe. After 2 rebuilt and one used trans we figured it out. It was bad speed sensors. I had my ecm re flashed, new valve body's in the trans's and I added an 1870 eliminator shift kit and none of it worked until I changed the speed sensors.

Funny you should mention ecm, because I have one and it has been flashed to my vin I just need to install and do the crank position sensor re learn and anti theft re learn procedure on it. So if the VSS does not cure it, I will try that next. VSS is a cheap try compared to what I have spent on it so far. I would have thought transmission shops would deal with these things daily and know troubleshooting procedure, but I must say the shop that did mine was chasing his tail, right up to the point of closing his doors after 25 years in business.