87 Regal T Type Tranny shifting....

[CWUSMC]

Ok I put a 350 from a 74 corvette into my regal I have a 350 turbo sitting behind it that I bought completely built with red line clutches and Kevlar bands the whole works - today it changed its whole stance on me..... It dosent go into 2nd gear until its at around 35-45 mph and when you hit 60-70 it shifts again

It chirps the sh*t out of the tires at 2nd gear that I dont mind but i would like for it to shift earlier i checked all fluid and she looks toped off

[maxwedge]

Have you adjusted the tv linkage properly?

[MagicRat]

Originally Posted by maxwedge

Have you adjusted the tv linkage properly?

As I recall, the THM 350 does not use a TV cable. That is used in the THM 700, THM 200 and THM440 transmissions.

The THM 350 has a modulator, which is essentially a switch that uses intake manifold vacuum to control the shifts.

Late shifting will occur if the modulator is stuck or the vacuum line has become disconnected or blocked.

The hot set-up is to use an adjustable modulator, because, when properly set-up, it can compensate for low vacuum conditions caused by long-duration cams.

[maxwedge]

My 350 in a street rod has kick down linkage that can alter shift patterns. I assumed after all the work he did the modulator would be properly connected, maybe you are right here.

[CWUSMC]

looking around I don't see any vacuum lines that arnt connected and the kickdown cable is adjusted correctly there about a 1/2 in of room for it to travel where its connected to the carb. - I have been manually shifting it and if I do it myself everything seems to be fine I'm wondering if the modulator went bad.

[MagicRat]

My money is on the modulator. Just check that the vacuum line going to the mod actually has full vacuum (I suggest use a vacuum gauge) at idle, before replacing it.

Originally Posted by maxwedge

My 350 in a street rod has kick down linkage that can alter shift patterns.

I had to look this up in my transmission rebuild manual. The THM 350's cable performs a more limited function than the TV cables in the 4 speed automatics. The manual refers to it as a kick-down cable, not a TV cable as such.... but as you say, if its out of whack the shift points will be incorrect.

[430-4]

hi, first thing to do is determine if it has a vacume modulator. small round vacume control device usally located on the passenger side toward the front of the tranny case on turbo 350's. let us know & we can go from there.

[HotZ28]

Don't forget to check the servo & governor springs. See pic below for locations.