TH350 shift points.

[Phoenyx]

OK, here's a question for all you TH350 guys.

Well first, if you don't know. I have an '80 Malibu with factory 305/350 combo. It's all original except dual exhaust and 3.73:1 gears. And it's got less that 50,000 original miles on it.

Now, I didn't notice it before I changed the gears. But now when I take off under light to half throttle it shifts funny. It shifts out of second so fast that it almost skips the gear, but not quite. At first I thought it was the transmission slipping. But after paying closer attention, I noticed it was just shifting from 2md to 3rd really fast. It almost feels like its got a powerglide in it lol.

SO, anyone else have 3.73s and a stock untouched TH350? And if so, does it shift like mine?

Or does anyone know what could be causing this?

It's OK under full throttle, shifts around 4000 RPMs in each gear.

I was planning on getting a shift kit installed this summer. But don't want to bother if the transmission is possibly on its way out.

Any suggestions?

 

[megaladon6]

what it might be is that with the new gears, the governor (which controls line pressure and therefore shift points) is spinning at a completely different speed than before. this makes it think you're going faster than you are and shifts at the incorrect time. also, i'd expect that your speedo is off.

 

[TBRtat2]

if you dont have one, you should get an adjustable vacum modulator. It will let you adjust the part throtle shift points.

The govener more controls the full throtle upshifts.

How does it shift when you are bearly giving it gas? (only as much as needed to get it going to speed)

 

[Phoenyx]

OK, first off. My speedo is right. i had it re,calibrated at a transmission shop.

And. When I'm barely on it, shifting is fine. It's also good when I'm at WOT. My problem is at part to mid throttle.

I was thinking about getting one of those adjustable vacum modulators when I get the shift kit installed.

 

[TBRtat2]

an adjustable modulator should take care of your problem.

 

[Phoenyx]

OK cool. Now a silly question. How hard are they to install? I've heard of and seen them, just never installed one.

 

[TBRtat2]

disconect line, take off one bolt, slide out old, slide in new, tighten bolt, reconnect line, adjust.
Thats about it.

if you want, you can go to most any autoparts store and buy it.
It came in some cars, stock.2
Fram part # FM2310
the fram part comes with directions too, if you need them.

 

[Phoenyx]

OK cool. I'm gonna be borrowing a buddies garage for a night or two pretty soon to install some 6x9s and change my battery (I live in Canada, so it's cold lol). So I'll put one of those in too.

So with the adjuster. Is somewhere around half way a good starting point?

 

[TBRtat2]

it comes already set to stock.

After that, just follow the directions in the box.

Also, check your vacuum line that runs it, make sure its not leaking, or cloged.