Cosmik Debris

I had my 700R4 rebuilt with the nice strong parts and a Transgo kit. It works very nicely. When the shop installed the Transgo kit it allowed the transmission to lock-up mechanically somehow. I think this method was used on some trucks fitted with 700R4s. It works OK but now I am installing an aftermarket EFI system, and it has the ability to control the lock-up via the original solenoid. Can I change the transmission back to electronic lock-up easily?

Cheers.

Apeiron

Possibly, or the two aren't mutually exclusive.

Cosmik Debris

Does anyone know how the Transgo kit achieves lock-up?

Apeiron

AFAIK the TransGo kit doesn't touch lock-up at all.

Cosmik Debris

Yeah it does. http://transgoonline.com/products.ph...dcountview=Yes

This states it allows lock-up with no wires. I guess I should ask them :-)

ASE doc

Transgo makes a TCC control valve that operates the TCC by pressure alone. To convert to electronic TCC control, you just need to switch back to the factory style TCC control valve train that works with the solenoid. Then you need to be sure that the 4th gear pressure switch and the brake TCC off switch are in place. Your after market ECM, if it's like the ACCEL DFI will activate the TCC, when the 4th gear pressure switch and TCC brake switch are closed) based on throttle position and engine rpm.

BTW, The Transgo TCC control valve is separate from the other Transgo shift modifications. Removing it will not affect your shifting.

vetteoz

iTrader: (13)

Would that not give lockup in 4th gear only?
Not during the gears to prevent TC slippage like the OP wants?

Cosmik Debris

OK thanks, that's what I needed. I guess I can do all this through the bottom without removing the trans.

Apeiron

Is their TCC valve very different from a factory non-computer one?

Apeiron

Is their TCC valve very different from the factory one? If not then the hydraulic and electric controls can co-exist, like the factory did on non-computer setups. The valve will control minimum lock-up speed and the electric controls can handle other conditions.

Cosmik Debris

This is what I was hoping.

ASE doc

I believe that the Transgo setup is intended as a a simple option for 700R4 swaps into early vehicles with no other simple way of controlling TCC lockup. I am pretty sure that the Transgo setup only provides TCC lock up in 4th gear. As far as providing lock up in lower gears, remember that TCC lock up is intended for reducing trans temps and fuel consumption in cruise conditions. I have never seen any OE vehicle that allowed lock up lower than 3rd(direct drive) gear. I would be concerned having the TCC lock up in lower gears that it might be hard on the gear train and also on the TCC itself.

With electronic TCC control, especially with an aftermarket EFI system, you could easily set the TCC to lock up in 3rd gear as well as 4th. It would be a matter of installing the right combination of pressure switches. On my ACCEL DFI system, the ECM activates the TCC above a given throttle position and a given engine rpm. The 4th gear pressure switch is what prevents the TCC from engaging in any gear but 4th. To allow the TCC to activate in a lower gear, I would simply need to add a pressure switch to the 3rd clutch circuit.

Cosmik Debris

The Accel DFI system is the one I'm installing. I was hoping that the solenoid and wiring inside the trans were still connected and all I would have to do is hook up the new ECU to the standard plug.

I had a feeling that the transmission shop said they had replaced the valve body to one that allowed mechanical lock-up, does that make any sense?

vetteoz

iTrader: (13)

Logic would say not if the TCC was converted to full mechanical operation

Makes perfect sense
In that case you would probably need to install a stock VB to achieve the stock elec control setup what you want

There are several on the C4 forums with drag cars that lock the convertor when they hit 2nd.
Report quicker ET's from reduced slippage
Not wishing to risk it I had the lockup completely removed from my race T700

ASE doc

Whether the TCC can easily be converted back to electric control would depend on what was done to make it mechanical.

I read an artcile about using early TCC engagement for faster ETs. Dana at Probuilt suggests that it be done only with the three clutch TCC as a stock TCC will not hold up under this kind of use. He also has found that with a converter correctly matched to the vehicle, there is no need for this.

smolek37k

iTrader: (4)

Hello,
I have a 1993 Caprice with the 700R and when I wanted to delay TCC lockup on my trans I used the Jet Performance TCC lock up delay module #61640. So far ok.