phxraptor

:confused: Can the 350C trans in my 81 (stock) be used as it came from the factory without the computer system being hooked up to it ? Since the lockup is controlled by the computer what will happen when it is not hooked up ? Will it operate just like a regular 350 ? :confused: :cheers: :seeya

Master Ho

The convertor on my '81 doesn't lock up, and it doesn't have any affect on the computer or viceversa. I get 3 crisp shifts, thanks to the shift kit.

Smokehouse69

One of the guys I work with has an 81 with the 350c, he has a non-computer distributor and a Holley 650 DP instead of the computer Q-jet. His convertor locks up, I have no idea how it is hooked up but when riding in it you can feel it lock and watch the rpm's drop when cruising at a steady speed over 40 mph. It must be hooked to the computer in some way, that doesn't require the rest of the stuff to be hooked up.
Maybe the lock up function of the computer only looks at speed and rpm to decide when to lock up.

Fevre

You can wire it to a switch for full manual control. Locking t/c are nice for dropping the rpm's a touch and reducing slippage that causes heat that can reduce trans life.

American Boy

I guess that the 1981 350 THC is the same as the 1980. No computer is needed in the operation of the lock-up. The lock-up system only need a 12 volts signal that passes thru the brake pedal switch and a vacuum activated switch located on the firewall driver side. The voltage activate a solenoid that let oil pressure to lock-up the converter. The speed reference is taken ( I think) via the governor of the transmission (hydraulic signal).

Stephan

MIKER

This diagram shows how the TH350C is wired on the non-computer 1980 models.

BSeery

what he said.

Twin_Turbo

if you intend to run without the lockup install an oil cooler. Without the lockup the tranny will generate a lot of heat.

You can buy lockup kits for carbed applications from painless wiring and others.

Steve81

:iagree: When I unhooked the ECU I used the B&M Converter Lock-Up Control #70244. It's a fairly easy install and hooks up to your speedo so you can adjust the lock-up speed and to the brake light switch to disengage or you can switch it on/off manually.