Automatic transmission shift-points?

BC847

BC847

New member
I'm fixing to upgrade/refresh my heap's automatic transmission. :)

I got to thinking about what I might change about the current transmission's valve-body and got to thinking about where's the best shift-point(s).

It's been my understanding that: You want the shift-points such that when you shift gears, have the next gear's clutch engage just before peak engine torque.

* How much you can wind a given gear is perhaps a secondary question. I know TransGo has/had a selection of VB springs that altered the go-to-next-gear shift-point once wound out.

My VE fueled 12v fuels hard in the lower engine RPM. As such, my peak engine torque is around 1900 ~ 2100(+/-). With that, the torque is rolling off kinda quick. The HP is relatively flat out to perhaps 3600 engine RPM. (I've recently increased the charge-air volume so, my numbers mentioned are questionable).



- Assuming a WOT condition, 47RH VB, and 48RE gear-train, what's the current strategery regarding trans shift-points?

Thanks, Guys. ;)


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*** I couldn't find any thread using "Shift-pints" or any variant in a Search, without the typical 300 general threads, all over the map. . . .
 
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I don't want to crap on your thread, but I got a full manual valve body just so I wouldn't have to think this hard. I take it you going to put your typical level of perfection into this project, so carry on with my respect.
 
You can change governor springs and such like outlined in the junker drag truck thread. Tuneability is still lacking that route, it helps if you change out the individual shift valve springs like you mentioned. I know the trans parts suppliers for the gassers running the 727 have quite the selection. You might look that route. After messing around with mine for over a year, i ditched the governor and machined custom plates to mount solenoids to actuate the 1-2 and 2-3 shift valves and then easily tune shift points with mega squirt.
 
Begle1 said:
I don't want to crap on your thread, but I got a full manual valve body just so I wouldn't have to think this hard. I take it you going to put your typical level of perfection into this project, so carry on with my respect.
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What about consistency though? Could get a lot more consistent with a well tuned transmission.
 
Anteater, problem solved. It'll shift whenver you want, in whatever shift pattern you prefer. With the ability to have 3 tunes to choose from on the fly
 
Thanks for the replies folks. :)

The thing with my heap (VE fueled) while the HP remains relatively flat out to 3600 or so, the torque is rolling off fast. Compared to the P-pumps and such, I need to shift gears much earlier as I don't rev as high as you guys . . . . . . I think.

That's the thing. It seems most aftermarket spool-valve springs available are for a shift-point higher than I think i need.

. . . .or am I missing the TV-valve adjustments and its impact on what I think I'm after.

I think need a VB bench and trans dyno thingy.



I need to call the folks at Suncoast and find out just how my current TC is set up. I . .. . think . . . . I want a new lock-up converter that's setup much like my current non lock-up converter . . . just with the lock-up devices (I'm leaning toward a triple-disc for the potential longevity . . in my application . .. . ? ).
 
jasonc said:
A lockup conv trans would be a huge upgrade.
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That's exactly what I'm doing. That being said, the new converter and input-shaft will be of the 48 series thus completing all the 48 geartrain less the output-shaft (the current is billet/alloy that plugs into my OEM NP205).
 
Any particular reason why I might switch from the Alto Reds to the Raybestos clutches? (I've got a number of spares).
 
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