200-4r gurus

[hammer4691]

Hello 200-4r Gurus,

I come to this forum because I know the smartest 200-4r people on the planet contribute to the forum. I have read and read and read before posting. Here is my story :

I own a 66 Nova SS. It is a hot little street car, with a SBC and about 400hp with 3:73 gears. It had a TH350 but I wanted an extra gear. I knew of the great gear spread the 200 had to offer, I knew I wanted one. I pulled one from a junkyard out of a Cadillac and dropped it off at a local builder who builds trannys for a speed shop. ( not a 200-4r expert) He rebuilt the trans stock and put a Transgo shift kit with a billet servo and a 2000 stall converter. Originally, he put in a BR governor but it would never shift at WOT, so we put the original one back in. I have since lightened the small weight and it now shifts at a little better RPM. I'm still tuning that. I use a vacuum switch to engage OD and that works fairly well.

When in D it upshifts fine at light throttle, shifts are firm and at the right time. In D once I get to 4th it will not downshift when I go to WOT. The clutch disengages and the converter slips but it never downshifts. I also get the 3-2 clunk when coming to a stop. When I drive in 3 the shifts are a little higher RPM and I do not get the 3-2 clunk. It will downshift. All my shifts in D or 3 seem firmer at light throttle than WOT.

The TV cable is set up correctly and has the geometry extension on the carb. I did hook up a pressure gauge last weekend and got these readings at 1500rpm at 0 TV and Full TV.
P 80 165
R 150 200
N 80 170
D 80 170
3 80 240
2 170 170
1 170 170

Before I discovered this forum, I was naive as to all the valve body combinations and the precise calibration they need. It currently has a KC4 valve body. I'm done working with my builder. He's a great guy and might be able to build a th400 for race cars but he clearly doesn't understand 2004r and way too busy to spend the time with me.

Do any of you have suggestions or see anything glaring ? I see that Extreme Automatics can set up valve bodies to perform like a BR. Is that my easiest option ?

Thank you,
Mark

 

[hensleyt]

Lonnie at Extreme Automatics in Ohio tech page shows your pressure are low.
He has built two transmissions for me and both worked perfectly for me.
There can be a real pissing mach over hard parts are who's are who's, and who's came first.
He dose build a BRC Valvebody The C stands for calibrated.
No body likes two spend money twice on a transmission but its problem going to be the hard fact of the mater.
We have 2-3 real builders who have been on this form Lonnie left a long time ago I have known him 15 + years. He is my go to builder.
Dave Huseks at TurboBuickPerformance left the forms a few year back our I just don't see him post much. He gets high marks too
Don't be tricked buy Taxes Art Carr I bought a TR with his box it was a pice of junk. Art Carr in Cal. I think is around.
I see someone post a lot TexesT he seems to know the 200 very good. I sure don't know it.
I have found a builder Lonnie. I pad $ shipping to hawaii when I lived there. His box worked and when I added 150 more HP he was there to help.He was up front and said his Stage I would be OK but I was at the limit for the forward drum, it might hold but might not.
Thats my 2 cent hope you got through the spelling mistakes.

 

[hensleyt]

I forgot to say Yes Extreme automatics valve bode is a option but call because your pressures look low.
Cant remember the guys name ( think it is Chris) that answers the phone there. BUT be prepared ,they are wound a little tight and talk fast.
Remember he is my goto man and I'm 100% happy.

 

[Mr.Spool]

Hello 200-4r Gurus,

I come to this forum because I know the smartest 200-4r people on the planet contribute to the forum. I have read and read and read before posting. Here is my story :

I own a 66 Nova SS. It is a hot little street car, with a SBC and about 400hp with 3:73 gears. It had a TH350 but I wanted an extra gear. I knew of the great gear spread the 200 had to offer, I knew I wanted one. I pulled one from a junkyard out of a Cadillac and dropped it off at a local builder who builds trannys for a speed shop. ( not a 200-4r expert) He rebuilt the trans stock and put a Transgo shift kit with a billet servo and a 2000 stall converter. Originally, he put in a BR governor but it would never shift at WOT, so we put the original one back in. I have since lightened the small weight and it now shifts at a little better RPM. I'm still tuning that. I use a vacuum switch to engage OD and that works fairly well.

When in D it upshifts fine at light throttle, shifts are firm and at the right time. In D once I get to 4th it will not downshift when I go to WOT. The clutch disengages and the converter slips but it never downshifts. I also get the 3-2 clunk when coming to a stop. When I drive in 3 the shifts are a little higher RPM and I do not get the 3-2 clunk. It will downshift. All my shifts in D or 3 seem firmer at light throttle than WOT.

The TV cable is set up correctly and has the geometry extension on the carb. I did hook up a pressure gauge last weekend and got these readings at 1500rpm at 0 TV and Full TV.
P 80 165
R 150 200
N 80 170
D 80 170
3 80 240
2 170 170
1 170 170

Before I discovered this forum, I was naive as to all the valve body combinations and the precise calibration they need. It currently has a KC4 valve body. I'm done working with my builder. He's a great guy and might be able to build a th400 for race cars but he clearly doesn't understand 2004r and way too busy to spend the time with me.

Do any of you have suggestions or see anything glaring ? I see that Extreme Automatics can set up valve bodies to perform like a BR. Is that my easiest option ?

Thank you,
Mark

Contact david husek.

 

[TexasT]

A stock KC vb is usually good for 6k or so shift points with a brf governor. You need some pump mods (.500 boost, larger rev/boost and the 700r4 spring) to get those pressures up. Not knowing what has ben done to the vb it is hard to make recommendations. Without the internal pressure at a sufficient level clutches slip. Not sure what you are using for the servo. Could be a small unit and the band doesn't have a chance with that and low pressure.

As above, a call to David H is highly recommended.

 

[hammer4691]

Thank you all to have replied. I have to change my speedometer drive gear, so while I am in there I will pull the boost valves out and measure them. If they are not .500" and .300" I will replace. I suppose this is my first step before I call anyone, so I have a good starting point. I found this on Sonnax Line Pressure Booster Kit - 700R4-LB1 Although it did not mention the size. If anyone can recommend parts it would be much appreciated.

Thank you,

 

[TexasT]

https://www.sonnax.com/parts/2940-reverse-boost-valve-kit

Depends how deep in you are going to dive. Might do a sonnax pump slide spring with the stock inner spring to up the pump volume at higher rpm. This requires pump removal and splitting it. The boost stuff can be done in the car with the pan off.
Might also look at the TV spring while the pan is down. A sonnax spring for that might help it too.

 

[GBGN1]

I agree the pressure is a bit low but that doesnt mean it wont downshift. Something doesn't add up. Whole problem could be in the valvebody depending what the builder did to it. The KC valvebody is a good valve body but if its been messed with too much youll have all kinds of weird issues. Having a BR valvebody isn't usually a cure . I'd pull it out and have it gone through again or if you have a stock valvebody laying around I'd throw that on and see if there is a change. That transgo kit I wouldnt recommend. I use the hd2 kit for parts (servo for steet use,extra direct return springs for dual feed, boost valves) sometimes but I never replace all the springs it offers in the kit for the valvebody. I bet if you return all the stock springs back to the valvebody youll be ok. But that will not address the low press issue.

 

[hammer4691]

I'll report back this weekend as to what I find with boost valve sizes. Isn't it odd that I get such different pressures between D and 3 ? Do you think a drill hole in the separator plate was missed, or could it be in the valve body? Just throwing out ideas.

 

[TexasT]

Pump might be suspect and not providing the volume needed to keep the pressure up. Hard to know without pulling it apart. With the line bias active it could be bleeding pressure off. Lots going on in that vb, and as above, without knowing what was done to it a lot of things could be happening.

 

[hammer4691]

Hello TB,

An update. I did call EA, spoke to Chris and also called Dave H. Both gentlemen took time to speak with me and tried to be as helpful as they could on the phone. Neither one could understand the difference between D and 3 and why it was acting the way it did. They also thought my pressures were low. They both also prepared me for the worst, ie: need another rebuild.

I wasn't ready to give up yet. I purchased 2 new boost valves from Sonnax with the O rings and PR spring. I also removed the valvebody and separator plate. I did find an anomaly. There was a missing or misplaced check ball. The exhaust relief check ball was in place so I moved that to the missing bathtub .

Put it all together and BAM all pressures between 80-240 psi no TV vs full TV. It now downshifts as it should.

Thank you to everyone who listed to my story and was willing to give feedback.

Hammer