TH350 shifts hard
 

My th350 shifts really hard from park to a gear and going down the road it shifts gears hard. I replaced the vacuum modulator and it still hard shifts.
My truck is a '76 gmc 1/2 ton k15 and used mainly for fishing. I'm afraid I'm
tearing stuff up with it shifting hard. I am also starting to wonder if someone put a shift kit in it. Is there anyway to tell without opening the trans.?

Re: TH350 shifts hard
 

sounds like a shift kit. do it shift hard only when your getting on to it?

Re: TH350 shifts hard
 

im gonna second the shift kit idea.... as long as the vacuum is good

Re: TH350 shifts hard
 

Check your fluid level as well

Re: TH350 shifts hard
 

I don't have to be gettin on it for it to shift hard. It pretty much does it all the time. Anyway to check it? who puts a shift kit in a gmc beater anyway, thats crazy to me.

Re: TH350 shifts hard
 

smell it too.if it smells like burnt toast,dont change your fluid you only going to make it worse

Re: TH350 shifts hard
 

Lol I have a shift kit in mine

Re: TH350 shifts hard
 

lol, i didnt mean to insult. Doesnt it bother you when it throws itself into gear like your waiting to drag race someone?

Re: TH350 shifts hard
 

make sure you are getting good vacuum from the intake/carb. i know mine was shifting real hard and it wasnt getting good vacuum. we gave it a good tune up(rebuilt/tuned carb, timed, etc) and it fixed the vacuum for the trans as well as the advance on the dist. runs great now.

Re: TH350 shifts hard
 

Thats my vote!

Re: TH350 shifts hard
 

Check for a cracked vacuum line. A low vacuum to the modulator will make your tranny shift hard.