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350 Turbo shift point adjustment question

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Old 12-25-2002, 01:56 PM   #1
dogboy
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Default 350 Turbo shift point adjustment question

Can I change the shift points myself? My old 350 used to shift at about 5000 rpm at wot. Since I replaced the unit with a summit 350 it shifts at 4500rpm. How can I increase that.
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Old 12-25-2002, 01:58 PM   #2
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Default Re: 350 Turbo shift point adjustment question (dogboy)

Shorten the detent cable and it will shift later. The proper "FACTORY" adjustment is obtained by having somebody hold the accel pedal to the floor, and you go under the hood. Press the button UNDERNEATH the spring-loaded guy-dude that holds the detent cable in the bracket. It is a D-shaped button. The spring will snap the cable right into place.
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Old 12-25-2002, 02:23 PM   #3
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Default Re: 350 Turbo shift point adjustment question (dogboy)

Good question! Something I have always wondered about. Mine shifts at 4500rpm also but is red-lined at 6000. You can shift the TH350 manually but I could never figure out why the transmission would not shift by itself at that rpm.
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Old 12-25-2002, 03:03 PM   #4
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Default Re: 350 Turbo shift point adjustment question (paul79)

Thanks dogboy for the thread.I was about to post the same shift problem only opposite of yours.
How do you get a TH400 with a shift kit to shift at say 5500 instead of over 6000 when my rev limiter cuts in?
I believe the TH400 has an electric set up.
Trying to avoid the inconvience of a return trip to my trans guy 47 miles away.





[Modified by 69er, 3:19 PM 12/25/2002]
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Old 12-25-2002, 03:06 PM   #5
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Default Re: 350 Turbo shift point adjustment question (dogboy)

I know there are more precise ways to adjust shift points, but how about an adjustable vacuum modulator?

I put one on my car to raise the shift points (you can't do 1-2 and 2-3 separately), but I haven't played with it to see what it's limits are (i.e., how close I can have it shift to redline at WOT).

Just a thought.
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Old 12-25-2002, 03:23 PM   #6
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Default Re: 350 Turbo shift point adjustment question (dogboy)

My car seems different from everyone elses. I gets up to 7000rpm before it shifts, then it chirps the tires. Keeps pulling throughout. All it has is true dual exhaust with no cats. Everything else should be stock...
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Old 12-25-2002, 03:49 PM   #7
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Default Re: 350 Turbo shift point adjustment question (Schmucker)

My car seems different from everyone elses. I gets up to 7000rpm before it shifts, then it chirps the tires. Keeps pulling throughout. All it has is true dual exhaust with no cats. Everything else should be stock...

If it is a turbo 350, then I suspect you have that detent cable pulled quite tight.
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Old 12-25-2002, 06:23 PM   #8
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Default Re: 350 Turbo shift point adjustment question (dogboy)

I thought that the full throttle upshifts were controlled be the govenor? If so then the govenor weights would need to ne lightened a bit to increase WOT upshift points. The modulator and detent cable will have an effect on the part throttle upshift points though. I could be wrong though since I dont have a great deal of expeirence with the TH350. Please straghten me out if I am.
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Old 12-26-2002, 12:16 AM   #9
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Default Re: 350 Turbo shift point adjustment question (jerryp58)

jerryp58,
I know what your talking about I just had my mod go out and went to get another one it had instruction on how to adjust it, haven't installed it yet still working on the ZZ4 install.
tom :jester
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Old 12-26-2002, 01:25 AM   #10
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Default Re: 350 Turbo shift point adjustment question (jerryp58)

It seems that the adjustable vacuum modulators work on a + or - of 2-4mph and not rpm....?
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Old 12-26-2002, 01:37 AM   #11
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Default Re: 350 Turbo shift point adjustment question (paul79)

The detent cable should control at what throttle position DOWNSHIFTS occur. In other words, how far do you have to have the throttle opened up before it will drop from 3 - 2 or 2 - 1.

Up-shifts should be by the governor, according to the parts description for the governor kit from B&M.

I have a 700R4 and a Turbo350 that both need to have the up-shifts changed, but my problem is at light or part throttle. They shift waaaaay too soon -- like around 1500 RPM.
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Old 12-26-2002, 08:39 AM   #12
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Default Re: 350 Turbo shift point adjustment question (paul79)

It seems that the adjustable vacuum modulators work on a + or - of 2-4mph and not rpm....?

I guess I just don't know enough about auto transmissions to understand exactly when shifting is supposed to occur. I guess shifting is all related to pressures in different parts of the trans and apparently, vacuum as far as the modulator is concerned.

All I really know is that before I put the modulator in, it would annoynigly shift from 2-3 at 1500-2000 RPM under "light" accelleration. Now, it will run to 3000-3500 before the 2-3 shift. Of course the MPH point of the shift went up too. I can't quote the numbers, but it was the same effect for the 1-2 shift.

So, if the instructions do quote MPH increments, I would think they would have to mean at a given load and the RPM would correspondingly shift up or down.
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Old 01-02-2003, 02:55 AM   #13
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Default Re: 350 Turbo shift point adjustment question (BSeery)

I agree with BSeery. I had adjustable modulators on both TH350 and TH400. All that did was fine tune the shifting on the street. But for WOT shifting I used govenor kits (B&M?) and even then I had to do some bench grinding on the weights to get it shifting where I wanted it, around 6200-6500.
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