shake

[83kid]

Hi,
I have a 1983 k10 with what i believe is a 1990, but deffinataly a 700r4
So when im sitting at a stoplight,once it turned green id accelerate pretty heavily, and at some point a few weeks ago when it went to shift from 1st to 2nd i would get a shake, if i let off a little the shake would be less, if i let off completely the shake would disappear
I only use up to 3rd (not OD, cause i have 33's on it and never go fast enough or get high enough RPMs to need OD), by just putting it in the spot on the prndl gauge that has a 3, 3rd.
Through other shifting, its fine, and under light throttle it wouldnt do it, not occasionally goes

Any clue what this would be?

thanks!

 

[MadOgre]

U joint?

 

[83kid]

Possibly, did one like a year ago, but its lifted and my friends trucks always eat them up... driveshaft doesnt move when you try to wiggle it/turn it, and it doesnt happen like 30ish which ive seen ujoint do it... its only when shifting... could that be it? It is the kinds of shake you get when its a u joint though, just i doubted it because of it only dsoing it when shifting

 

[MadOgre]

Transmission mounts?

 

[83kid]

What could i do to test for those?

Also, my main question here is... Am i gonna have to do any work to the transmission? Seems odd that itsonly between 1st and 2nd no matter the little it of difference in speed your moving when it shifts

 

[MadOgre]

I dunno. @HotRodPC

 

[HotRodPC]

Very possible a cracked sunshell. #1 Problem with 700r4's is broken sunshell. You're obviously hasn't let go completely if that's what it is. The Sunshell will affect 2nd 4th and Reverse. Problem is usually first noticed in 2nd, and not as noticeable in 4th with lower rpm, and reverse almost not even detected until it lets go completely then you won't have reverse either. Not sure that's your problem, but if you used OD you might notice some issue with OD too. Though I wouldn't push it and try it unless you're prepared to remove it and tear it down. If it is cracked, using it in OD may be what does it in for good.

 

[HotRodPC]

The correction for this issue is to have a Sonnax Beast Sunshell or GM SmartShell installed.

Here are some different pics of the Beast.

Top pic is difference between OEM and Beast. The Beast is reinforced at the splines.

 

[83kid]

Very possible a cracked sunshell. #1 Problem with 700r4's is broken sunshell. You're obviously hasn't let go completely if that's what it is. The Sunshell will affect 2nd 4th and Reverse. Problem is usually first noticed in 2nd, and not as noticeable in 4th with lower rpm, and reverse almost not even detected until it lets go completely then you won't have reverse either. Not sure that's your problem, but if you used OD you might notice some issue with OD too. Though I wouldn't push it and try it unless you're prepared to remove it and tear it down. If it is cracked, using it in OD may be what does it in for good.

Only thing i think that may elimate this is that it only does the shake between 1st and 2nd, not in first, not in second, but between it.. could this still be it?