Trans-go kit question

[Sal Lubrano]

I was curious why they drill the servo piston and install an orifice. What is the reason for making this hole smaller? I also noticed they put one washer on the bottom of the 3-2 piston and two on top? They also leave out the 3-piston seal ring as well? What would be the reasons for all these modifications? Was watching the video they have and I was trying to understand all their modifications. Thanks for the help.

 

[V6RACER]

If that is the kit where you drill a hole through the VB then slowly step away... and get another brand.

 

[Sal Lubrano]

LOL. I am not installing it. Just trying to understand what they are trying to do.

 

[mikestertwo]

It's done to increase the apply rate of the 2nd gear band.

 

[V6RACER]

LOL. I am not installing it. Just trying to understand what they are trying to do.

Ok...

It's done to increase the apply rate of the 2nd gear band.

Yep.

 

[Sal Lubrano]

Thank you for the replies. I was looking for a more technical answer. Trying to learn how all these mods work. Thanks.

 

[jimski]

Thank you for the replies. I was looking for a more technical answer. Trying to learn how all these mods work. Thanks.

I was alaways curious about how they worked also.Good point

 

[mikestertwo]

Thank you for the replies. I was looking for a more technical answer. Trying to learn how all these mods work. Thanks.

Ok, here goes. The intermediate servo is a two piston design, a small piston inside a larger piston. When 2nd oil pressure is applied the smaller piston applies first putting a moderate amount of pressure on the band. It is then followed by the larger piston which puts a greater amount of force on the band because of it's larger diameter. This gives you an apply rate that gives you a smooth 1-2 shift and the correct timing for the 3-2 down shift. What some shift kits do is eliminate the small piston in the circuit by taking the seal off the small piston and plugging or putting a small orifice in the feed hole. With this mod you are now only using the larger piston to apply the pressure to the band. Using only the larger piston increases the apply rate to give you a firmer shift feel.

 

[darkhorsebob]

The center piston(steel) is the 3rd gear accumulator. It's purpose is to cushion the 3rd gear apply. It has nothing to do with applying the band. Eliminating the sealing ring from the piston quickens up the 2-3 shift.

 

[mikestertwo]

The center piston(steel) is the 3rd gear accumulator. It's purpose is to cushion the 3rd gear apply. It has nothing to do with applying the band. Eliminating the sealing ring from the piston quickens up the 2-3 shift.

Read the GM manual. It will enlighten you

 

[77 cruiser]

Read the GM manual. It will enlighten you

x2

 

[210 Sport Coupe]

Good ol' Trans-Go,

Bought their Trans-Go 200-R4-HD2 kit. (NEW)
Guppy plate missing, 2 valvebody gaskets missing, oh and yes a 700-R4 pan gasket and no filter, and their tech help wasn't very helpful. Yes package was unopened, still with plastic wrap inside tray and outer box.
Asked about what their video showed and compared to my instructions, his reply "that is only for reference"
HELLO.... kit and video were both referring to 200-R4 trans! WTF!!

No wonder I couldn't find a pic on-line of what their kit contains.

Should have got a kit off the vendors here.
Live & learn I guess.

 

[matt69olds]

trans-go ?

Good info, always wondered the reasoning behind some of Trans-go mods. What is the 'guppy' plate for, and why does nobody else use it? Is it really needed, or just a marketing tool so the customer thinks he is getting his money's worth? What is the deal with plugging the "F" hole in the plate? I have installed a couple of the Trans-Go kits, and CK's kit is MUCH better in my opinion. Chris has really done his homework as far as I'm concerned!

 

[darkhorsebob]

If you're leaving off the sealing ring on the steel piston, how is that helping to apply the band?

 

[mikestertwo]

If you're leaving off the sealing ring on the steel piston, how is that helping to apply the band?

You are only using the larger aluminum piston to apply the band. That's why the feed hole is either plugged or a small bleed orifice is installed. The steel piston is used as nothing more than a spacer. Using just the larger of the two pistons to apply pressure to the band increases the "apply rate" to the band.

 

[darkhorsebob]

My point exactly. The large oem spring and steel piston were for the 2-3 shift feel. The 700R4 uses the same approach.
Aftermarket servo assemblies do not use these parts.

 

[Sal Lubrano]

Excellent thread this turned out to be. Thank you for all the info. After looking at a servo tell me if I am correct. 2nd gear oil is fed through the pin to the top and fills the large aluminum piston but since there is an orifice it also fills the smaller steel piston area as well. Since the steel piston is small it will fill first applying first then the large aluminum piston will apply. Trans-go puts an orifice in the aluminum piston to control the apply rate of the large piston by bleeding some of the oil in to the smaller piston area and deletes the seal on the steel piston. The smaller spring is the first cushion while the larger spring cushions after some travel of the pin.
Now let me see if I understand the washers. I see bu putting washers under the steel piston it is stiffening/omitting the large spring. But I can not figure out what is the reason for putting washer on top of the steel piston?
Now when it comes time for 3rd gear the directs apply and the band needs to be released together. So, 3rd oil is sent under the steel piston and since there is a larger area under than on top the band pushes off.
Please correct me if I am wrong. So, much to learn. I am loving it!