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Old 06-26-2018, 10:59 AM   #1
Gregski
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Turbo 350 Transmission Don't Feel Shift 2 to 3

Hi guys/gals

I am no automatic transmission expert, (prefer a good ol' fashion 4 speed) but my 69/71 2WD 350/350 stock torque converter I imagine, 1/2 ton GMC is an automatic.

The problem is, if it can even be a problem, heck maybe this is normal, is that I don't feel the shift from 2nd gear to 3rd gear but watching the Tach I do see a quick drop in RPMs so it appears to be shifting.

So starting in D ie 1st gear I start from a dead stop and depending how hard I accelerate it will shift to 2nd gear anywhere between 1500 around 2100 RPM. But it seems to be going 1st... 2nd/3rd (2nd then 3rd that quick, shift shift)

instead of 1st... 2nd... 3rd...

When I shift gears manually I get all the gears so I know 3rd gear is there as are all the others, the shifter on the column works fine if that helps

I removed and inspected the governor and it appears to be in working order the weights expand freely.

I replaced the red stripe modulator with another red stripe one and tested it with a vacuum, though the original may have been just fine. I may have also turned it (the screw inside) both clockwise and counter clockwise to get more of a kick in the pants feel from shifts and no difference.

the kickdown cable is brand new and properly connected/adjusted (ie the free play) to the 1407 3028 Edelbrock carburetor.

Help me please
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Old 06-26-2018, 03:49 PM   #2
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

My shift from 2nd to 3rd is the same - barely perceptible - but also I know the shift is happening. I am guessing it is normal...
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Old 06-26-2018, 04:35 PM   #3
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

Is TV cable connected and properly adjusted?
Is a manifold vacuum line connected to modulator?
Is modulator good?
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Old 06-26-2018, 06:09 PM   #4
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

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Originally Posted by OregonNed View Post
My shift from 2nd to 3rd is the same - barely perceptible - but also I know the shift is happening. I am guessing it is normal...
Shifts like my wife's Honda Pilot so it can't be normal for a MAN's TRUCK, lol
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Old 06-26-2018, 06:10 PM   #5
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

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Originally Posted by demian5 View Post
Is TV cable connected and properly adjusted?
Is a manifold vacuum line connected to modulator?
Is modulator good?
yes, yes, and yes
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Old 06-26-2018, 06:14 PM   #6
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

Looks like I need an Automatic Transmission Governor Recalibration Kit

TH350 Governor Adjustments (Tranny Guys Wanted)

I swear I have better luck doing a random Google search and finding stuff on our forum than actually using this forums search.
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Old 06-26-2018, 06:58 PM   #7
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

That will just delay or shorten your shift. If you want a solid feel to the 2-3 shift, you can buy a reasonably cheap shift kit that will firm it right up. I used the cheapo B&M kit back in the '80s in a Chevy Vega I had, and it would chirp even going into 3rd. Having a GT engine and 3.36 axle helped a lot with that, I will admit. It was also a panel "truck", so no rear seat, just an extra storage compartment. Nice light little vehicle. Nobody but the DMV considers it a truck, but having panels instead of rear side windows forced me to have it weighed and to get commercial plates. 1/4T truck! I used to buy, fix and sell those critters. If I had known beforehand, I'd have popped in some glass from a wagon in my batch of Vegas as a temporary measure.
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Old 06-27-2018, 12:11 AM   #8
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

Quote:
Originally Posted by Steeveedee;828944[B
...If you want a solid feel to the 2-3 shift, you can buy a reasonably cheap shift kit that will firm it right up...
Yep, remember, Chevrolet wanted Grandma and Grandpa to glide down the ol' blvd. in total luxury, with their smooth shifting full size Capris sedan.

...nevermind that it wears out the friction plates faster and probably makes the thing run a little hotter on average as well.

A shift kit like a B&M is definitely a step in the right direction.

Comes with very good step-by-step instructions, follow to the letter and take your time.

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Old 06-28-2018, 09:45 AM   #9
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

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Originally Posted by Steeveedee View Post
That will just delay or shorten your shift.
that is really what I am after, I may have misspoke above or mislead you guys

Quote:
Originally Posted by Steeveedee View Post
If you want a solid feel to the 2-3 shift, you can buy a reasonably cheap shift kit that will firm it right up.
I skierd to install one of those, so I will save it as last resort.

Quote:
Originally Posted by Steeveedee View Post
I used the cheapo B&M kit back in the '80s in a Chevy Vega I had, and it would chirp even going into 3rd. Having a GT engine and 3.36 axle helped a lot with that, I will admit. It was also a panel "truck", so no rear seat, just an extra storage compartment. Nice light little vehicle. Nobody but the DMV considers it a truck, but having panels instead of rear side windows forced me to have it weighed and to get commercial plates. 1/4T truck! I used to buy, fix and sell those critters. If I had known beforehand, I'd have popped in some glass from a wagon in my batch of Vegas as a temporary measure.
hello my Californian brother, we had a blue station wagon vega back in the mid 80's ourselves, and yes our DMV is a force to be reconed with, ha ha

Last edited by Gregski; 06-28-2018 at 09:55 AM.
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Old 06-28-2018, 09:52 AM   #10
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

found this Superior brand Governor spring and weight kit on eBay for half the price ($47) of the TCI or B&M ($76) kits sold on Summit.

Superior, so it's gotta be good, says so right there on the box "Technology That Works" as oppoed to those who sell technology that doesn't work, ha ha
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Old 06-28-2018, 11:01 AM   #11
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

found these excellent GOVERNOR RECALIBRATION KIT Installation Instructions be it for the B&M brand

here are a couple highlights:

"The B&M Governor Recalibration Kit will allow you to raise or lower, relative to vehicle speed, the points where your transmission shifts." well that sounds like exactly what we are looking for

it goes on to say:

"The B&M Governor Recalibration Kit will not substantially change the quality, or crispness of the shift. This is done by recalibrating the valve body of the transmission." good to know, as some of you have already pointed out above

and here are the gold nuggets of information:

"Heavier weights produce earlier shifts, lighter weights produce later shifts."

"Stiffer springs tend to produce earlier closely stacked shifts, weaker springs tend to raise and spread apart shift points." aha that's what we need, weaker springs so that the shifts are further apart as the hot rod gods intended
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Old 06-28-2018, 11:10 AM   #12
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

Gregski, don't be skeered of that B&M shift improver kit. I'm no mechanic, far from it, I just do basic maintenance and minor repairs in my carport. I installed one of those kits in my TH350 many, many years ago and have never had a problem with it. Job is easy and the supplied instruction are great. Shifts are RIGHT NOW, sometimes you want to work the throttle a bit to keep it from slamming hard gear-to-gear. I have never regretted doing this mod, if you want quick shifts then go for it.
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Old 08-10-2018, 12:06 PM   #13
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

ok, Game On
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Old 08-10-2018, 07:06 PM   #14
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

so I decided to weigh all the middle weights as they call them and my original ones to get an idea what my current setting was

as it turns out mine weighed approximately .4 ounces or 11 grams, I switched the scale to grams to get a more better accuracy as the ounces was rounding off too high

A - .5 oz or 15 g

B - .5 oz or 12 g

C - .4 oz or 11 g (same as my OEM weights)

D - .3 oz or 7 g

E - .2 oz or 5 g

F - .2 oz or 5 g
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Old 08-10-2018, 07:07 PM   #15
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

and here's a look at my governor in the wild
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Old 08-10-2018, 07:09 PM   #16
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

and here we go cutting off those factory nails and taking things apart
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Old 08-10-2018, 07:12 PM   #17
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

and here's the anatomy of an automatic transmission governor

after all that showing off with the weights, I decided to start off by simply swapping to the lightest springs (so one purple and one red), I really don't get why they don't give you spring pairs, ie two red springs, two purple springs, etc.

there is a reason why they give you a few extra E clips as they call them, they tend to wonder off the kitchen island during reassembly, LOL
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Last edited by Gregski; 08-11-2018 at 10:28 AM.
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Old 08-10-2018, 07:56 PM   #18
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

I like your scientific testing results. That's some cool shift.
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Old 08-10-2018, 08:04 PM   #19
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

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I like your scientific testing results. That's some cool shift.
ha ha, yup this shift better work!
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Old 08-10-2018, 08:16 PM   #20
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

I'm paying attention to what you're doing as I just picked up a used TH350 for my 69. I'm about to drop the pan on it and see what's in the pan. Fluid smells good. If it looks good inside I'm thinking about a mild shift kit and run it. I am interested in moving the shift points if it needs it too.
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Old 08-11-2018, 10:09 AM   #21
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

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there is a reason why they give you a few extra e clips as they call them, they tend to wonder off the kitchen island during reassembly, LOL
I've heard them called "Jesus" clips and "Oh S##t" clips for that reason. And they don't just wander, sometimes they full on shoot towards the far corner of the room.

Cool stuff, thanks for sharing all of the details and pictures. This could come in handy if I am ever brave enough to peek inside my TH350!
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Old 08-11-2018, 12:35 PM   #22
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

My first suggestion would have been to attach a vacuum gauge to the line at the modulator and check vacuum sweep. Hook up the gauge and snap the throttle, the needle should sweep immediately. If not there could be a carbon build up where the metal line attaches to the manifold allowing a build up of vacuum in the line itself. Remember to attach the gauge at the line where it attaches to the modulator.
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Old 08-11-2018, 02:31 PM   #23
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

not sure if I mentioned this but I forgot to lift the butt of the truck up in the air when I removed the governor this time like I did the last time so I got covered in trans fluid (well sort of) but it did drain a ton

don't be me
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Old 08-11-2018, 02:32 PM   #24
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

well that sucks, just completed the first test drive after going to the lightest springs, now the transmission does not shift at all, top speed is 30 MPH at 3,500 RPM, also I am unable to shift gears manually you know, L1, L2, D

so gonna let her cool and going to try a middle of the road spring combo I'm thinking an Orange / Green pair
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Old 08-11-2018, 02:34 PM   #25
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Re: Turbo 350 Transmission Don't Feel Shift 2 to 3

Quote:
Originally Posted by Sharptrans View Post
My first suggestion would have been to attach a vacuum gauge to the line at the modulator and check vacuum sweep. Hook up the gauge and snap the throttle, the needle should sweep immediately. If not there could be a carbon build up where the metal line attaches to the manifold allowing a build up of vacuum in the line itself. Remember to attach the gauge at the line where it attaches to the modulator.
thanks I tested the line and the modulator's response to vacuum and even replaced the modulator for a brand new one already
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