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Discussion Starter · #1 ·
Okay people,
Many years ago I put a B&M transpak shift kit in my turbo 400. I did the street and strip version and second gear hit like a wrecking ball. The car got stored for 10 years and now I'm putting a BBC 489 in it. I want to go to more of a towing kit in it or perhaps a hybrid kit between the two. I'm sure you guys in the know know how to do that.
Anyway, I gotta calm down that 1-2 shift as it's just too hard for my liking. With the 408 BBC I have in the car now, under full throttle it hits so damn hard I fear the rear end will blow apart!
So folks, I plan on buying another B&M transpak but where do I get check balls? I had taken three out when I did the kit years ago.

Also, while I'm bending your ear, I did a hybrid kit in a turbo 350 years back, but can't remember what I did. But the manners were perfect. In town the gear change was instant but under light throttle you didn't feel it. At moderate acceleration it was firm but not neck snapping. Under full throttle going from first to second it would give out a light chirp from the tires but didn't hit like a wrecking ball. That was in a 77 Nova with a 350 engine and 3.08 gears.

This is how I want my 400 to act if possible. Any Ideas?
 

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Any trans rebuild parts supplier can supply the check balls, you can get them in either hard rubber or steel.
1/4" steel ball, like a ball bearing works just as well.

TransPartsOnline shows them for $0.56 each.
 

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By chance did you remove the 1-2 accumulator spring? If so reinstall it. Also do you plan on installing a higher stall torque converter? A higher stall converter will soften the shift. I personally don't like installing shift kits that delete check balls or springs. A Turbo 400 if built correctly can be made to shift very good without installing a shift kit that deletes parts.
 

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Discussion Starter · #4 ·
By chance did you remove the 1-2 accumulator spring? If so reinstall it. Also do you plan on installing a higher stall torque converter? A higher stall converter will soften the shift. I personally don't like installing shift kits that delete check balls or springs. A Turbo 400 if built correctly can be made to shift very good without installing a shift kit that deletes parts.
I honestly don't know. I did whatever the kit told me to do for street and strip. I will print off the instructions to see what I would have eliminated so I can buy the parts.
 

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Discussion Starter · #6 ·
I need to learn more about transmissions I guess so I can tweek this more to my liking. It is just plain too violent right now. But, I don't want to go back to mush either. I will be running about a 2800 stall with 3.42 gears but don't know if that affects anything
 

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leaving check balls out... in the T-400 often the 1-2 check ball is removed. This will create a harsh 1-2 shift you mention. Depending on year of the T-400 case , it may have 6 or 7 check balls. I would install all of them and look at the size of the 1-2 shift hole. A .110 size hole with check ball installed will produce a moderate shift in most average applications
 

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Discussion Starter · #8 ·
leaving check balls out... in the T-400 often the 1-2 check ball is removed. This will create a harsh 1-2 shift you mention. Depending on year of the T-400 case , it may have 6 or 7 check balls. I would install all of them and look at the size of the 1-2 shift hole. A .110 size hole with check ball installed will produce a moderate shift in most average applications
This is good to know. Given the things I had to do to install the B&M transpak, will just replacing that check ball calm it down enough or do I need to redo the accumulator too?
 

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Discussion Starter · #9 ·
Any trans rebuild parts supplier can supply the check balls, you can get them in either hard rubber or steel.
1/4" steel ball, like a ball bearing works just as well.

TransPartsOnline shows them for $0.56 each.
Thanks again eric, I bought the check balls today from that sight. Super cheap in my book.
 

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Discussion Starter · #10 ·
Okay, now I'm confused. The B&M transpak which is what I installed shows you change valves and pump pressure, leave the accumulator alone and drill one hole for the street and strip version. The shift improver kit has less stuff but you mess with the accumulator and drill two holes in the plate for the street and strip version. If you mixed these two kits would all hell break loose?
I ask because all I really need is the plate and gaskets and check balls to ease up the shifts.
I hope this isn't a dumb question because I don't know much about transmissions or what modifications do what.
 

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If you’re going to leave the pressure regulator spring in,I would just drill the new plate,both holes to 5/32.
Put back all the check balls and leave everything alone. Keeping the holes smaller,you can always go bigger
if you want the shifts firmer.This is what I would do.
 
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