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Discussion Starter · #1 ·
The 1985 T1 Log motor/A413 Trans in my 600 is all stock, and in decent shape. I'd like to take my time and build up a new motor and transmission "the right way", which will take a while.

In the meantime, I'd like it very much if my A413 didn't crap out from just putting a Gus valve on the motor. Also, I just can't stand the shifts. I hear tell that those slow, accumulator shifts heat up the trans a lot. If I start valve-body mods to improve the shifting, will that increase or decrease the reliability of my transmission? If they'll help my trans life, I'll kill two birds with one stone!

Also, what exactly do the shuttle valve mod and bypass valve mod accomplish? I understand the accumulator bypass and the passage enlargements, but not these two mods.

Thanks so much!

Tyler
 

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The shuttle and bypass valve mod improve the 2-3 shift. When adding a G-valve to an automatic car, keep in mind that you'll be able to build full boost at part throttle. Because the line pressure in the trans is raised via throttle input, full boost at part throttle will cause slippage. More slip= more heat.

Raising the line pressure while performing the shift kit mod (and compensating with governor weight changes), will allow the trans to have more clamping power from 0-100% throttle. The trans will not run as hot and will live longer (all things set aside).

Running a two stage boost controller is the best way, IMO, to have high boost with an automatic trans.

-Chuck James
 

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The shuttle and bypass valves are known as "timing" valves. They control the timing of the 2-3 upshift and 3-2 downshift In other words, they control the timing of the kickdown band releasing as the front clutch is applying (during and upshift), and vice-versa on the downshift. The valves accomplish this by routing the fluid through different sized orifices. When you block the valves from moving, you essentially "lock" the valves in position so the fluid passes through the bigger orifices at all times. Hope this helps answer your question.

Chad Kilback "D&D Racing" (Calgary, Alberta SDAC)
88 Daytona Shelby "Zedd"
12.43 @ 111 quickest time
12.6 @ 113.00 fastest time
87 New Yorker "Norker Zedd" 2.5L TII 14.6 @ 93
 

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Discussion Starter · #5 ·
Yes it does, thanks! :cool:

So, as before, will these mods, all other things being equal, make the transmission more or less durable? Obviously, they'll make it drive better. :)
 
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