Sticks In 2nd In a Slow-n-Go Condition

[Blown&Injected]

Could too much pressure in the form of a shim between the Throttle Valve Spring and Throttle Valve Plunger cause a trans to stay in 2nd gear when doing a slow and go, as in a fast to slow to 1 MPH, or less, at a stop sign? If I stab the throttle as I pull away, it will pop into 1st.

Thanks

 

[77 cruiser]

It could if your line press. is too high @ min. tv.

 

[Blown&Injected]

I just gave this a bit more thought - if I stab the throttle, that ups the line pressure as it cranks the TV cable - right?

At first I'm thinking the shim might be causing more pressure and preventing 2nd from releasing - BUT I Really Do Not Know What Effect This Shim Has On The Trans in the first place.

It seems like, maybe the governor???, or something else is calling for 1st gear and succeeding even with more TV due to the extra throttle.

Your Help Is Greatly Appreciated!
Thank You

 

[Lee Thompson]

line pressure

Not being an expert (If I'm off, someone please correct me), I will take a stab at this.
There are 2 spools in the TV valve assembly. 2 springs also. This happened to me --If the large spring is stroking the small valve when @ idle or min. TV, it will raise line pressure as if you are giving it throttle. The shim will in effect make the spring longer. This raises the pressure over 90 PSI (mine was 110). I had second gear starts and would not down shift to First @ a slow down. With the VB out and upside down you can view the small valve through a hole in the VB. I thought I read in Chris's manual that the ideal clearance between the large spring and small valve is .001. But I cannot find it now.I put small washers in behind the large spring to get it out to where it is just off the TV valve. Right or wrong this is working good for me. Best of luck. Ain't it fun dropping the VB to get what you want. That is the difference between just OK and getting it RIGHT.

 

[Blown&Injected]

Thanks Lee

I have the trans out right now and would like to put it back in. Although it is possible to yank the roll pin that holds this stuff together with the trans in the car and without pulling the VB off but it is still so much easier to work on while it is out
so
It would be nice to hear from some of the experts here - please

I took the washer out hoping that it will lower the pressure by making the spring shorter/less pressure

 

[Lee Thompson]

vb

While you have the trans out, flip it and remove the vb. You will be able to shim it to near 0 clearance. Maybe one of the Builders will reply later tonight. I am curious also.

 

[77 cruiser]

You don't happen to know what your line press. is @ min. TV do you?

 

[Blown&Injected]

No idea what the pressure is. The trans is out and I did not check it while it was in the car.

I will pull the VB to check the clearance on that spring too.

Thanks guys!!!!

 

[Nordbert]

Plunger to spring clearance

I think this is the thread that Lee Thompson was referring to in his October
28th 2:27 P.M. post. KLHAMMETT started the thread.

http://www.turbobuick.com/forums/showthread.php?t=68670&highlight=valve+body+experts+read

 

[Lee Thompson]

bingo!!

I guess I am not going crazy. I knew I had read that some where.

 

[Blown&Injected]

Just getting around to looking into this and am a bit confused - I only notice 1 spring in the VB diagram for the TV. I see there are 2 roll pins but it only shows the #43 TV Spring; then a place where a shim is to go in the kit I have (now removed); then the #44 TV Plunger; the #45 TV Plunger Bushing that the #44 part gets inserted into; then the final roll pin.

Actually my VB kit instructions say to install a part over the small end of the #41 Throttle Valve. Maybe this is the 2nd spring?

Lee, exactly what valve and spring are you talking about when you say the small valve and the big spring? I think I may be considering the wrong valve.

Well I'm going in and will report my findings and leave it all open pending some more feedback.

Thank You All Very Much!!!!!

 

[77 cruiser]

305 is the TV plunger 304 is the TV spring red arrow pointing to the TV return spring.

http://webpages.charter.net/77cruiser/VB diag..gif

 

[Blown&Injected]

Thanks for the diagram - I was looking at a different schematic that I thought had the same part numbers - I was wrong about that but you still managed to correctly interpret my mumbelings and even provide me with answers to questions I did not even have yet. - Damn your good!

I actually measured the spring I thought I needed to look at, # 304, and now I know the proper size too.

Upon looking at the ATSG diagram I now see what I sort of found. I took both roll pins out and yes there was a second spring, # 346, the TV Boost spring and the kit I have used a very light tiny spring that slips over the Throttle Valve, # 302, a description of that extra (third) spring may be a "helper" spring. It looks like it adds a tiny extra amount of pressure to the # 302 Throttle Valve kinda making the # 346 spring a tiny bit stronger.

It also looks like that "helper" spring and the # 346 TV Boost Spring move with the Throttle Valve = zero play. - So What Do You Think?

TIA

 

[Lee Thompson]

look

Install the small spring (Yes, the other one is a helper or insurance spring)--small spool (TV valve ) then roll pin. Now look down through hole and see where the TV valve sits @ home position. Install rest of assembly and see if it has started stroking the TV valve without you moving the large plunger by hand. If it has, you will have BOOSTED line pressure @ idle. Not what you want. You want the TV valve to start moving as soon as you start stroking the large plunger, not before. Clear as mud now?