Recommended upgrades for 700R4 "in car"
Thread Starter
TECH Regular
Joined: Oct 2011
Posts: 453
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From: Alaska
Recommended upgrades for 700R4 "in car" For one of my projects I'm installing a fairly low mile 700R4, and I'm looking for recommendations for things I can do to this transmission "in car". As in, I can remove the pan, valve body, servos, etc, but I will not be tearing into the internals at all. It's strictly a cruiser/street truck, no racing, probably around 350hp, spirited driving. I just want to give it a decent chance at living for a while. I figure some type of shift kit, and larger servos are a given, but I'm unsure of what would be the best for what I need.
TECH Junkie
Joined: Dec 2012
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From: Iowa
.500 boost valve, 2/4 band servo-"corvette" would probably work best, accumulator springs (selected based on how hard you want it to bang shifts), hd2 shift kit (if youre willing to pull valve body), drill separator plate. I'd enlarge 2nd apply to .093, 3rd supply to .110, 4th apply to .100, and reverse to .100 everything else whatever transgo instructions say.
TECH Resident
Joined: May 2006
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What year is the transmission? As mentioned the Corvette servo, .500" main boost valve. Add the .296" intermediate/reverse boost valve for firmer 1-2 manual shifts and a better reverse. If you want to hold 1st gear to any rpm without it shifting then the 700-2-3 would be necessary. If you leave it in drive and let the transmission shift on its own when racing it, then modifying the TransGo Junior Shift kit will do here. What rear end gear ratio? What torque converter are you using here or plan on using here? The holes mentioned are close, but there are even improvements here depending on what you have here. Lastly how do you drive? Conservative? Moderate? Moderately aggressive? Or aggressive?
Thread Starter
TECH Regular
Joined: Oct 2011
Posts: 453
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From: Alaska
Thanks for the input both of you. Pulling the valve body is no issue, I just won't be going into the pump or internals. The truck is 1986 and I believe the trans to be original but I haven't date coded the case. 3.73 gear ratio, stock converter for now (I think stock is 1400-1800, but I may bump that up in the future if the trans ever gets a rebuild). It'll be driven moderatly to moderately aggressive, but strictly street driven, no racing.
TECH Resident
Joined: May 2006
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If it is a "1986" transmission, then the Shift kit from TransGo to use here is the "full shift kit" also known as the "Senior 700R4 Shift kit". The hole sizes with the above information is "A" (3rd gear) = .110". "B" (2nd gear) = .076". "C" (3-2) = .125". "D" = .125". "E" (4th gear) = .125". "F" (band release) - .093". DO NOT install the orange spring on the 3-4 shift valve, use the green spring. Otherwise the 3-4 shift will be very late. Remove the spring from the 3-2 valve in the valve body. Install valve and pin only. This will make for a much quicker 3-2 downshift. All this with the Corvette servo and boost valves will make a world of difference in how the transmission shifts and behaves.
