700r4 with reverse manual build
03-27-2018, 09:29 PM
#1
700r4 with reverse manual build
Hey guys, I’m dropping off my 700r4 on Friday to a very popular and highly rated performance transmission builder. I’m going with a reverse manual valve body and have a couple questions.
The builder talked about going with a constant pressure valve body and eleminating the tv cable’s control of line pressure. I’m worried that the constant pressure will be too hard on the trans and cause issues. Any thoughts on this?
i also read that the th350 guys have to worry about the trans free wheeling when shifting from 3rd to 2nd and sending shrapnel into their legs, is this an issue with the 700r4? Does the 700r4 engine brake in all gears with a manual valve body?
my final question is on downshifting. a lot of people say to only downshift when at a complete stop but many people also say it’s fine to do if you rev match it, what is the trick to downshifting a reverse manual valve body without causing unnecessary damage to the trans? Thanks
The builder talked about going with a constant pressure valve body and eleminating the tv cable’s control of line pressure. I’m worried that the constant pressure will be too hard on the trans and cause issues. Any thoughts on this?
i also read that the th350 guys have to worry about the trans free wheeling when shifting from 3rd to 2nd and sending shrapnel into their legs, is this an issue with the 700r4? Does the 700r4 engine brake in all gears with a manual valve body?
my final question is on downshifting. a lot of people say to only downshift when at a complete stop but many people also say it’s fine to do if you rev match it, what is the trick to downshifting a reverse manual valve body without causing unnecessary damage to the trans? Thanks
03-28-2018, 06:59 AM
#2
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Car: 89 Formula
Engine: 383 SBC/HSR
Transmission: 700R4
Axle/Gears: 3.73
Re: 700r4 with reverse manual build
I have one in my car and no TV cable is needed since it's constant pressure. I have a TCI valve body, which provides you with different springs to control shift firmness. I also played with the 2nd & 4th super servo spring, to get it to shift firm but not harsh.
I have the VB with engine braking in all gears, since I only drive on the street now. I downshift while moving just fine, even if I don't rev match exactly it just slows the car down like a normal 700R4.
TCI Part# 376010 -No engine braking
TCI Part# 376015 -With engine braking
I have the VB with engine braking in all gears, since I only drive on the street now. I downshift while moving just fine, even if I don't rev match exactly it just slows the car down like a normal 700R4.
TCI Part# 376010 -No engine braking
TCI Part# 376015 -With engine braking
Last edited by heat seeker; 03-28-2018 at 07:16 AM.
03-28-2018, 07:40 AM
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04-04-2018, 06:17 AM
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Re: 700r4 with reverse manual build
Having worked on many hundreds of 700R4's, I would not use a "constant pressure" valve body. Too firm a shift at light throttle and not firm enough at WOT. It is hard on front pump. I have seen many of these failing to keep the transmission alive for very long. For the gentleman getting 2 years and driving it on the street too (not drag racing only) is to me a record. As I have never seen one work for long when used on the street. Even when drag racing only, I prefer to have variable line pressure based on throttle opening, as this is much easier on the geartrain. If you have any questions about this, let me know.
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04-04-2018, 10:01 AM
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Car: 89 Formula
Engine: 383 SBC/HSR
Transmission: 700R4
Axle/Gears: 3.73
Re: 700r4 with reverse manual build
Having worked on many hundreds of 700R4's, I would not use a "constant pressure" valve body. Too firm a shift at light throttle and not firm enough at WOT. It is hard on front pump. I have seen many of these failing to keep the transmission alive for very long. For the gentleman getting 2 years and driving it on the street too (not drag racing only) is to me a record. As I have never seen one work for long when used on the street. Even when drag racing only, I prefer to have variable line pressure based on throttle opening, as this is much easier on the geartrain. If you have any questions about this, let me know.
Last edited by heat seeker; 04-04-2018 at 10:28 AM.
04-04-2018, 10:36 AM
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Car: 89 Formula
Engine: 383 SBC/HSR
Transmission: 700R4
Axle/Gears: 3.73
Re: 700r4 with reverse manual build
Don't see why they can't change the VB to what you want. I've changed one of my 700R4's from a full manual back to an auto with no problem. You just change out the VB/plates and put the accumulators, checkballs, governor, and pressure regulator back. It's not that hard if the transmissions already open.
04-04-2018, 12:33 PM
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Re: 700r4 with reverse manual build
I am not aware of a reverse manual valve body that uses the TV cable. As you said you have to put back the 1-2 accumulator. I forgot that they removed this component. No wonder that they shifted so hard at light throttle. It is fine to disable the 4th accumulator, just not 2nd or 3rd. The TransGo modified Shift kit that I make could be setup for "full manual", it would be a forward shift pattern which is the only way to build a full manual in my experience.
04-04-2018, 12:44 PM
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Car: 89 Formula
Engine: 383 SBC/HSR
Transmission: 700R4
Axle/Gears: 3.73
Re: 700r4 with reverse manual build
I am not aware of a reverse manual valve body that uses the TV cable. As you said you have to put back the 1-2 accumulator. I forgot that they removed this component. No wonder that they shifted so hard at light throttle. It is fine to disable the 4th accumulator, just not 2nd or 3rd. The TransGo modified Shift kit that I make could be setup for "full manual", it would be a forward shift pattern which is the only way to build a full manual in my experience.
I'd like to build another 700r4 and try it.
Last edited by heat seeker; 04-04-2018 at 12:51 PM.
04-04-2018, 12:59 PM
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Re: 700r4 with reverse manual build
You will use your valve body 1988 & up to make the necessary changes. What is it you want to do exactly??? What is your motor setup? Torque converter diameter and stall? Rear end gear ratio? How you drive? Etc. Do you want a "full manual"? Or a automatic and the ability to manual shift it past 5,000 rpm?
04-04-2018, 01:23 PM
#15
Re: 700r4 with reverse manual build
You will use your valve body 1988 & up to make the necessary changes. What is it you want to do exactly??? What is your motor setup? Torque converter diameter and stall? Rear end gear ratio? How you drive? Etc. Do you want a "full manual"? Or a automatic and the ability to manual shift it past 5,000 rpm?
04-04-2018, 01:39 PM
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Car: 89 Formula
Engine: 383 SBC/HSR
Transmission: 700R4
Axle/Gears: 3.73
Re: 700r4 with reverse manual build
Sounds like you're just wanting to hold any gear for WOT up-shifts. You can do that with a modified VB. If you're driving in traffic, you're not gonna want a RMVB. I do open road cruising, not in traffic.
Last edited by heat seeker; 04-04-2018 at 01:46 PM.
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