200r4 upshifts

[Mr70Monte]

I have a 200R4 from an 86 MCSS in my 70 Monte, I rebuilt it about 6 years ago & it has worked fine since then, I have about 15K miles on it, last fall I had the car out to a local show, the trans shifted great then. Now the last 2 times I have had it out this year, I have to let off the gas to get it to upshift at part throttle, WOT shifts great. part throttle shifts are very hard, but they have always been firm, It has Bruce's shift kit in it, along with his TV valve & pressure regulator kit. I have the TV cable adjusted correctly @ WOT. running a edelbrock 1901 quadrajet & a performer series cam, other than that its a stock 300hp 350.

any ideas on what to check first.

thanks

 

[chris718]

sounds like a sticking inner tv valve.disconnect tv cable and pull it 20 times in and out with the engine off and then on.reconnect cable and road test.post results.

 

[Mr70Monte]

Chris,

I've removed the pan, just to check the TV valve & cable, it was not stuck. I have also been running the fluid about a 1/2 qt. full.

I can't figure out what it could be, does the governor have anything to do with part throttle shifts, or does it only control the shifts at WOT.

Could it be something to do with the pressure circuit? should I hook a gauge up to it & see what kinda presures its making, I would think it has to be something that is common to 1-2, 2-3, 3-4 shifts.

 

[chris718]

time for the gage:smile:

 

[gsgns4me]

Chris,

I've removed the pan, just to check the TV valve & cable, it was not stuck.

The valve that sticks can't be seen by just removing the pan. The TV valve is to the right of the spring in the following picture.....

The part you see the cable moving is just a plunger, and yes if the valve sticks it will affect all the shifts....

 

[77 cruiser]

The valve that sticks can't be seen by just removing the pan. The TV valve is to the right of the spring in the following picture.....

The part you see the cable moving is just a plunger, and yes if the valve sticks it will affect all the shifts....

Exactly but you should be able to feel the valve moving by pushing on the plunger as there's a light spring on the end of the TV. Should push in about a 1/2 in. & then you'll be compressing the heavier plunger spring.

 

[Mr70Monte]

Chris,

here's the pressures that I got

1000rpm--------------1500rpm
Min TV....Max TV------Min TV....Max TV

P 215........220---------300........300
R 170........175---------235........235
N 215........215---------300........300
OD 170........185---------210........250
D 170........190---------215........250
2 170........190---------225........250
1 165........175---------215........235

 

[77 cruiser]

Looks like it's stuck press. @ min. tv should be around 90.

 

[Mr70Monte]

here's what I have done,

I removed the pan again today, I then removed the TV linkage, removed the pin holding the TV plunger & sleeve in, then the spring, I could move the TV valve by inserting a small screwdriver into the bore, it appeared to move about 1/2", I'm guessing there is a pin that holds the TV valve in place, but I didn't see it (might be removable from the top side of the valve body)

But now I know the TV valve itself is free.......where do I go from here/

Thanks for all your help....Craig

 

[chris718]

the inner tv valve is stuck.

 

[chris718]

remove the valve body,check the valve again.install new gaskets retorque valve body and very pr valve in pump or tvboost valve in pump is not sticking.

 

[77 cruiser]

Wonder if the TV limit could be stuck, not sure if that would give the same symptoms or not, but if you pull the VB might as well check.

Valve Body

 

[Mr70Monte]

update.....

I pulled the transmission & removed the pump, because the .570 TV boost valve & .400 boost valve were sticking. Cleaned out everything & got them moving freely & reassembled them & the pump back in the transmission, hoping to get it put back in this weekend.

I hope my problem is gone.

Thanks for all your help!

 

[jakeshoe]

I had the same problem with a .570 boost valve. Where did you get it?

 

[chris718]

i saw that as well .that is why i mentioned it.the boost valve was machined off center.it looked like an old outer sleeve was milled out and then fitted with a new inner valve.

 

[jakeshoe]

The one I had issue with was simply poorly machined. Too rough of a cut.
I can buy .500 boost valves for $4, and they are machined better than the .570 I used from a vendor here.
$100 in the garbage.