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Lengthening shift points in a TH350

6K views 8 replies 6 participants last post by  Igosplut 
#1 ·
Can someone please give me some ideas on how to prolong the shift from 1st to 2nd gear? Also i know that i can adjust 2nd to 3rd gear with my modulator but is there any other ways to prolong the shift? The tranny im working on is a TH350, with a B&M shift kit.
 
#3 ·
i have an Delta 88 with an Olds 350/Th350 and I have the same problem. I am NOT a mechanic. but I would like to know how to change this problem. My transmission will not shift out of FIRST gear until 50 mph and between 35-49 I get hardly ANY acceleration. All i hear is the flowmasters (gotta love the roar!) but as soon as I hit 50, it kicks in and I'm flying again. Can anyone help me?

after reading the first post again, I have the exact opposite problem, but I still need help
 
#4 ·
D88 said:
i have an Delta 88 with an Olds 350/Th350 and I have the same problem. I am NOT a mechanic. but I would like to know how to change this problem. My transmission will not shift out of FIRST gear until 50 mph and between 35-49 I get hardly ANY acceleration. All i hear is the flowmasters (gotta love the roar!) but as soon as I hit 50, it kicks in and I'm flying again. Can anyone help me?

after reading the first post again, I have the exact opposite problem, but I still need help
You probably have a sticking governor.

It's located toward the rear of the tranny and has a cover that resembles a master cylinder cover (with a wire type retainer). You can remove it and clean it making sure the valve moves freely in it's bore. Beyond that I would do a pressure test (will need a guage or take it to a shop), cause it could be a number of things in the valve body itself.

Usually the transmission will not return to first gear when coming to a stop. Meaning you will be taking off in second or even third gear (possibly explaining the lack of acceleration).
 
#5 ·
D88....

If the tranny shifts the same all the time, I would also look at the vacuum feed to the tranny. Check the modualtor for oil where the vacuum hose attaches. No oil should come from the niple where the vacuum hose attaches.

Also check the detent cable from the carb to the tranny. IF it's not hooked up, check the cable to see if it is pulled, stuck , melted or something. This will tell the tranny you have your FOOT into the engine and the tranny should shift late.



BIG86.....

Are you working with part throttle shifts or WOT shifts?





Big86inthestixx said:
Can someone please give me some ideas on how to prolong the shift from 1st to 2nd gear? Also i know that i can adjust 2nd to 3rd gear with my modulator but is there any other ways to prolong the shift? The tranny im working on is a TH350, with a B&M shift kit.
 
#6 ·
Crosley's da'man.:thumbup:

D88, make sure to check the vacuum to the modulator as well as the modulator itself FIRST as well as checking for a froze detent cable. Do what I suggested LAST. :embarrass :D
 
#8 ·
WOT shifts controlled by govenor, modulator and vacuum have little affect on shift point. Part throttle shifts controlled by modulator pressure being overcome by govenor pressure, modulator and vacuum have large affect on shift point. Spring behind modulator valve will lower part throttle shift points as will turning out the screw in an adjustable mod. Turning in the screw or removing the spring (which is not stock and put in as part of some shift kits) will increase part throttle shift points. Detent cable on 350 controls kick down only, if stuck will cause late part throttle shifts but no effect on WOT shifts. If disconnected it can cause WOT shifts to be early but no other problems. If cable/detent valve isn't stuck and you have a good vacuum modulator, and good vacuum to it and still have concerns with your shift points, get yourself a govenor recalibration kit. Heavier springs and weights lower shift points and lighter springs and weights raise them. Springs have more effect on part throttle shifts and weights have more effect on WOT shifts, but both affect both shift points to some degree, so some trial and error will be required. Good luck.
 
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