Trans PR valve and access

[W30post]

I'm new to this site and new to working on the 200 4R trans. Sorry I know htis was covered in another thread but I cannot find it now. I just went through removing the pan this weekend to try to change the boost valve spring. I only saw access to the TCC valve snap ring, after removing the TCC, and the hole for the filter adaptor. Does someone have a picture of what I am missing? Is the boost valve hidden under the valve body? Any help would be greatly appreciated.

This is an 85 GN trans, BQ if I remember correctly.

 

[mikestertwo]

It's on the opposite side from the lockup solenoid in the pump. You have to rotate the gear selector detent into the manual low position and you will see the snap ring. The detent covers it when it's in the park position.

 

[W30post]

That would explain why I could not see it. Thank you for the info.
Where can I get the upsized boost valve?

This trans is basically stock GN with a TransGo NoYoYo kit mostly installed. I get some flare(if this is equivalent to slip feel) going into third. All else feels pretty good. Will the boost valve help get the shifts a little more firm.

Anything else I can do easily? This is a 72 Cutlass with a mild 455. It will be driven mostly on the street and will not be driven very hard.

 

[W30post]

Let me start over on the last post.

Is there a pressure regulator valve update that can be installed while I have it out? Transgo suggested a 0.420" valve for V8 cars. You guys seem to know a lot more here that I have researched thus far. Where could I get one and what do I ask for?

Is a boost valve located in the Throttle valve assembly of the valve body and will it help with better shift preformance?

 

[mikestertwo]

IMHO transgo shift kits are junk. Superior makes a much better one. You can get an updated pressure regulator valve from GM. The large boost valves are available at most rebuild shops (.500"). The boost valve along with the reverse boost valve goes over the top of the pressure regulator valve in the pump.

 

[wickedtt]

Performance Transmission Services

 

[bison]

If you have a flair i doubt that the boost valve by itself will cure it. .500 is the one i use in all my transmissions. Do you have any pressure readings for us? Verify that its a BQ. Its painted on the side of the vb You will need to increase the rate of the pressure rise. I would bet your engine has 500+ ft-lbs of torque. I would dual feed and use teflon sealing rings on the center support with alto reds in direct. A billet shaft forward drum should be installed to prevent shaft breakage when dual feeding. Once you get a flair under torque you usually hot spot the steels and burn the clutches and its down hill from there.

 

[WE4]

Ck these out:

Product Information
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And the complete system:
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These are the best in the land, ROFL but, they are!:biggrin:

Bruce
WE4
Performance Transmission Services

 

[W30post]

If you have a flair i doubt that the boost valve by itself will cure it. .500 is the one i use in all my transmissions. Do you have any pressure readings for us? Verify that its a BQ. Its painted on the side of the vb You will need to increase the rate of the pressure rise. I would bet your engine has 500+ ft-lbs of torque. I would dual feed and use teflon sealing rings on the center support with alto reds in direct. A billet shaft forward drum should be installed to prevent shaft breakage when dual feeding. Once you get a flair under torque you usually hot spot the steels and burn the clutches and its down hill from there.

First off, thanks for all the infromation that is on this site and the knowledge of the people here. Sorry for the long post on this one but it has some possibly important details about the car.

This motor makes roughly 460 ft.lbs. I stayed mild because I wanted to lock-up the converter. Some older version of Desktop Dyno spit out 385 HP and 465 torque, but that is all I have to base it on. The shifts were pretty firm until I installed the Transgo, not knowing about this site at the time, and now they are a little soft. The 1/2 shift is fairly firm under any throttle position but the 2/3 leaves a little to be desired. I have been chasing some problems with cutting the seal on the servo while trying to finish the install which helped get the 1/2 shift back to firm.

Couple questions, will the larger of the two boost valves require any modifications in the pump? This pump also has the original drain back holes. Will going to the larger of the 2 boost valves cause seal blow out?

No I haven't had a chance to get pressure readings from the trans yet. From reading the information Bruce has provided in the sticky posts, it is quite possible I have some clearance issues on the pump rotor and such. As the fluid gets warm I do get a little more lazy of shifts. Before you ask, I rerouted the cooling lines away from the manifold and installed a stack type cooler in front of the radiator do reduce temps as much as possible. Is there anything else I need to do for cooling? I do not have trans temps yet.

Oh the trans is to the full mark. I still run the factory filter and pan and D5 converter. After I change the boost valve I will run the trans a quart higher than the stick says, from reading here.

Stats on the car, 3600 without driver, roughly 380 hp 460 lb-ft torque, 3.42 posi. This car is a full exhaust car and will not see any track action. It will be driven on the street and will be run through the gears every now and then.

Will be ordering a boost valve late this month and will install it before I get pressure readings. I gotta say I love the way this car drives with OD and lock-up. I get right on 20 MPG.

 

[bison]

I would get some pressure readings before you go any further. Even before you change the boost valves. Does the shift quality improve if you manually shift the trans? The pump does not require mods. The valves and spring are a simple replacement. You need a set of pliers for internal snap rings. I would have drilled the passages to be on the safe side. The drain back holes should be enlarged. If the pump rotor and slide was replaced and the clearances were not checked and reset more than likely have a clearance issue. Depending on where the pump was sourced the replacements are usually to tight unless you ordered the pump from GM and had a lot of luck.

 

[W30post]

I would get some pressure readings before you go any further. Even before you change the boost valves. Does the shift quality improve if you manually shift the trans? The pump does not require mods. The valves and spring are a simple replacement. You need a set of pliers for internal snap rings. I would have drilled the passages to be on the safe side. The drain back holes should be enlarged. If the pump rotor and slide was replaced and the clearances were not checked and reset more than likely have a clearance issue. Depending on where the pump was sourced the replacements are usually to tight unless you ordered the pump from GM and had a lot of luck.

Truly this is a case of I have no clue what I have. I took some guys word that the trans was rebuilt. He bought it from the rebuilder but could not give any specifics on what was done.

When I first installed it in the car, it drove great. Nice firm shifts in all gears but there was a nagging problem. No matter how short of a trip, or long for that matter, if I turned off the motor and restarted too soon (no idea of how soon) it would cut loose on third if you raised you foot and would not go to fourth. Anyone here seen that problem? The Transgo kit did help this but I did not change the PR spring like the kit said to as I could not find the darn thing. Therefore I believe the pressures will be weak because of the drilling and other modifications.

The car is garaged for a couple weeks until I figure out what to do. I don't want to damage it anymore than what may be there. I do enjoy driving it but my budget on this car is shot and I don't have the money to spend on internal trans work right now if it has to come out of the car.

 

[bison]

Drop the pan and see if its clean. What hole sizes did you use and what holes did you plug if any? You may want to contact Chris at CK or Bruce at PTS to aquire one of their shift kits. They are much better than the Transgo kit and are very easy to install. They also have more specific instructions for high torque applications. You still need to verify pressures though since your pump assembly is a mystery. Hopefully the rebuilder did not just change out the pump slide, rotor, and vanes with aftermarket parts. You would be better off with the stock pump unless the pump is blueprinted when those parts are replaced.

 

[W30post]

Bison,
Actually, the pan was very clean. As for holes in the valve body plate, I followed the Shift Kit to a tee. That is one hole plugged and all holes opened up to the larger size of the kit dimension. I don't know how to describe where they are at this point.

I talked with Bruce today and described what I am seeing. First off, he seems like a guy that wants to help people understand these transmissions and that is unusual for smeone that has never talked with me and I haven't bought anything from him so Thanks. From what I understand I don't have the flare condition. I have a soft shift condition instead. Bruce asked some specific questions that I have to get answers back to him and you before I do too much else.

One of my main concerns was band tightness while installing the shims on the servo. I believe I should use the one additional shim in the kit to firm up the 3 and 4 gear shifts. Here is why I say that. I installed the single shim first without plugging the servo. This gave a soft shift to second and third. I took it back apart, without dropping the pan and installed the second shim and plugged the servo. This immediately gave me no shift feel for second and what appeared to be a good third. I talked with a local shop and they said too tight could cause no shift so I took the pan off to see how dirty the fluid was and I thought I would take the shim out of the servo. Upon inspection, I had cut the outside piston seal the last time I installed the servo cover. So I installed just the single shim again and the servo with a new seal. This gave good second gear feel but third is soft again. That is a lot of information. :redface: The true engineer would have changed one thing at a time like leaving 2 shims, but I get ahead of myself.

Bruce wants to know which pin I have in the trans. I told him I would get that information this weekend but it may be a little longer. I do know that the servo pin to servo has some wear that will cause some leakage. How much wear? That has not been determined but a billet servo and new pin may be in order shortly.

Here is the tough part for me. I want to drop the pan only one more time if I can help it. I am really starting to hate the smell of trans fluid and the way it makes my house smell. Therefore, I want to buy the PR valve, TV valve and install at one time. I also want to know how to determine if the apply pin has enough tension for the band. Gut feel is the second shim needs to go back in but I would like to be more sure. With the second shim in, I could barely move the band, with it out the band was pretty darn loose. Kit said 1/8 inch of movement with servo cover in place. I don't think I could get that much movement with 2 shims installed, but my hands were saturated with trans fluid and I may have been able to move it better with dry hands.

Again, thanks to all that have replied to this thread. I know there is a wealth of information you guys are providing for free. The thing I do appreciate about my conversation with Bruce today was, he did not give me crap about having a Transgo kit installed. Instead he just tried to help me work through this issue.

Bruce thanks man