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1project2many · 11-28-2012, 01:57 AM

Sorry. I guess that I forget this is still new territory for many people. Designing and wiring a simple control circuit for TCC can be a simple process. Having a trans shop do it may help but there have been soooo many changes and upgrades to that trans that you may leave the shop with your head spinning and your wallet substantially lighter. Nothing wrong with using the shop but it's a good idea to remain focused if things start to get out of hand.

There are many different combinations that can be used to achieve converter lockup. One way to approach it is to list some of the requirements or conditions.

For example: GM used a dual brake switch or a separate brake switch that was normally closed but would interrupt power to the TCC when the brakes were applied. If you do not have a provision to use the OE style brake switch and cannot add a separate switch then the relay in the posted circuit will do the same job.

The 4th gear pressure switch should be a fairly easy item to find. One source for transmission parts is TranStar. They are a fairly large supplier of trans kits and parts Transtar GM catalog. I have purchased directly from them before but they may frown on it for small purchases. However, a local trans shop could get what you need through them. The normally open / pressure closed switch part no. 8627332 was originally used for "Transmission Controlled Spark" on turbo 400's and is available through Transtar as part no 34414. The THM400 connector part no 24205373 is Transtar part no 34444A.

Vacuum switches are often easier to source through aftermarket sources. From the kits previously linked, the "fully adjustable vacuum switch" is a desirable item. I believe that was from TCI. A less expensive but similar part made by Superior co is available through Transtar as part no 74439A. Here's an Ebay link to one of those switches. 14014519 is available through the aftermarket as Standard Products VX2. The pigtail is somewhat unique and is probably better than the slim spade connectors. The price of the Standard part is near the price for the adjustable switch so I'd probably opt for adjustable.

The light in the posted circuit is on whenever the TCC is locked. To me, I don't need a light to tell me "All systems are functioning OK" but one which indicates "potential problem here" is better. Also, on long trips or at night I might find the light that is on more than off to be annoying. A simple change, wiring the light in parallel to the vacuum switch, would cause the light to illuminate only when the trans is in 4th gear, the engine is under enough load so the vacuum switch is open, and the brakes are not applied. I can draw a circuit for you when you decide which components you will use.

11-28-2012, 01:57 AM	#17
1project2many Registered User Join Date: Mar 2012 Location: Lakes Region NH Posts: 3,158	Re: 700r4 swap questions Sorry. I guess that I forget this is still new territory for many people. Designing and wiring a simple control circuit for TCC can be a simple process. Having a trans shop do it may help but there have been soooo many changes and upgrades to that trans that you may leave the shop with your head spinning and your wallet substantially lighter. Nothing wrong with using the shop but it's a good idea to remain focused if things start to get out of hand. There are many different combinations that can be used to achieve converter lockup. One way to approach it is to list some of the requirements or conditions. For example: GM used a dual brake switch or a separate brake switch that was normally closed but would interrupt power to the TCC when the brakes were applied. If you do not have a provision to use the OE style brake switch and cannot add a separate switch then the relay in the posted circuit will do the same job. The 4th gear pressure switch should be a fairly easy item to find. One source for transmission parts is TranStar. They are a fairly large supplier of trans kits and parts Transtar GM catalog. I have purchased directly from them before but they may frown on it for small purchases. However, a local trans shop could get what you need through them. The normally open / pressure closed switch part no. 8627332 was originally used for "Transmission Controlled Spark" on turbo 400's and is available through Transtar as part no 34414. The THM400 connector part no 24205373 is Transtar part no 34444A. Vacuum switches are often easier to source through aftermarket sources. From the kits previously linked, the "fully adjustable vacuum switch" is a desirable item. I believe that was from TCI. A less expensive but similar part made by Superior co is available through Transtar as part no 74439A. Here's an Ebay link to one of those switches. 14014519 is available through the aftermarket as Standard Products VX2. The pigtail is somewhat unique and is probably better than the slim spade connectors. The price of the Standard part is near the price for the adjustable switch so I'd probably opt for adjustable. The light in the posted circuit is on whenever the TCC is locked. To me, I don't need a light to tell me "All systems are functioning OK" but one which indicates "potential problem here" is better. Also, on long trips or at night I might find the light that is on more than off to be annoying. A simple change, wiring the light in parallel to the vacuum switch, would cause the light to illuminate only when the trans is in 4th gear, the engine is under enough load so the vacuum switch is open, and the brakes are not applied. I can draw a circuit for you when you decide which components you will use. Last edited by 1project2many; 11-28-2012 at 02:03 AM.