1975 TH400 Hyrdamatic Transmission question

[lastryde]

Hello all!

Well I finally got my 75 SS running and driving down the road and I discovered that it is very sluggish shifting. Now I did just rebuild the carb and I thought I hooked up everything correctly. I have also drained the trans fluid, replace the filter, and pan gasket.

Is there another reason other than the transmission is going bad. I'm hoping it is just something easy like the vacuum line had become disconnected to the transmission

Thank you everyone!

Lastryde

[Boogeyman Con Carne]

I would indeed check vacuum lines first, especially since you just had the carb off. The transmission vacuum port should be at the rear of the manifold or at the rear base of the carb.

[SmoothNlow]

Yup, when I first took my 69 on it maiden voyage I was devastated by a TH400 that wouldn't shift at all. Hooked the line up to find sluggish unconsistant shifting. Line had a pinhole in it. A quick change of the vacuum line and she was shifting like a dream. Good luck man.

[lastryde]

Thanks Guys,
When I got it out on the road I had to get the transmission almost whining till it would shift into up into 2nd, and shifting into 3rd I had to do the same as 2nd but when it shifted into 3rd it jerked hard and then smooth driving the rest of the way. Shifting into reverse is a bit rough too. If it does not engage the first time then I have to shift through all the gears and back into park then back to reverse and it works.

[lastryde]

I looked at some of the transmission parts would it be possible that the vacuum modulator went out?