You all have been very helpful....thanks again. I started a new thread to invite more folks...I have more questions.

I am going to replace my lock up selonoid...sounds easy enough. I still don't know a lot about lock up though. Assuming that the lock up selonoid is causing the OD vibration and it goes away when I replace the part...should I wire it to lock up in 2nd? Or 3rd? Have any of you done this?? Should I just leave it alone? I don't want to ruin my tranny in any way (no kidding...who does?), but I don't mind harmless mods. What do you all think?

How do I wire it if I decide to do it?

 

I personally do not like it to lock up in second or third. I prefer 4th lockup only. To do this put a normally open pressure switch in the 4th gear pressure port. Run terminal a to the red lead of the solenoid and run the ground to the 4th gear n/o switch.
Before you "poke and hope" on the solenoid, ohm test it. 20-40 ohms is normal with 22-25 being typical.

 

Wow you rock

 

Thanks:o .
Not really though. Lock up is a fairly easy curcuit. By using pressure switches in the prefered ports, it is easy to manipulate lock up to suit your needs.
The 4th only lock up is very popular with carbed, street rod and classic car retro fits. There is no computer in these cars and this method seems to be the prefered, simple, easy way to do it.
Years ago, before I knew anything about transmissions, I paid $70 for a silly harness that did the same thing.

 

Pete, would you mind explaining to me (and everyone else) what lock up does? I thought it slowed you down. I have now heard that it makes you go faster? What does it mean when a torque converter locks up? And will I smoke my tranny if I drive it in D with the connector unplugged?

 

I think not using a lock up on most automatic transmissions for daily driving causes them to overheat. True?

 

The early year 700's would die a fast death with the lock up not working. Later units had a pump mod that prevented that.
However, lock up will reduce the operating temp of your transmission and give better gas mileage. It will also extend the life because of the reduced heat. That is why I said to fix it in a previous post.
Lock up is pretty simple.
In a torque converter, fluid is transfered from one side to another by using 2 sets of fan blades. I set is welded on the inside of the converter and another set floats in the center. When the engine spins, the fluid is shoved to the other side spinning the fan blades. One will always spin faster than the other. This ineffeciency will cause heat to build. The lock up converter has a large plate with clutch friction material bonded to it. When the solenoid opens, fluid works a valve, sending fluid into the area that moves the lock up plate. The plate jambs agains the back side of the converter and "locks everything internal up"
Now, the converter has zero slippage. It and the entire contents are turning 1:1. Gas milage goes up, heat goes down. Except for the added weight of the lock up plate, it is all good.
Some guys manipulate when the converter locks up during a 1/4 mile run. Some say, if done right, it will improve et. Every car is different. My car did not like to lock up on the track. My buddies 92 f-body with a 434 gained 2 tenths when locked up at 90mph.

 

Thanks Pete. Well articulated. How do I go about locking up the other gears for the track? Do I lock up 2nd and 3rd? Just 2nd? Just 3rd? I'd like to try it and see what it does.

 

Most guys lock 3rd only and they start experimenting with 80mph and gradually go higher till they find the sweet spot.This can be done with custom programming or with a toggle switch wired into the diagnostic port or by splicing into the brake pedal switch. The color of the wires escapes me. It has been over 10 years since I have done it.

 

[QUOTE=Pete K]The early year 700's would die a fast death with the lock up not working. Later units had a pump mod that prevented that.
However, lock up will reduce the operating temp of your transmission and give better gas mileage. It will also extend the life because of the reduced heat. That is why I said to fix it in a previous post.
Lock up is pretty simple.
In a torque converter, fluid is transfered from one side to another by using 2 sets of fan blades. I set is welded on the inside of the converter and another set floats in the center. When the engine spins, the fluid is shoved to the other side spinning the fan blades. One will always spin faster than the other. This ineffeciency will cause heat to build. The lock up converter has a large plate with clutch friction material bonded to it. When the solenoid opens, fluid works a valve, sending fluid into the area that moves the lock up plate. The plate jambs agains the back side of the converter and "locks everything internal up"
Now, the converter has zero slippage. It and the entire contents are turning 1:1. Gas milage goes up, heat goes down. Except for the added weight of the lock up plate, it is all good.
Some guys manipulate when the converter locks up during a 1/4 mile run. Some say, if done right, it will improve et. Every car is different. My car did not like to lock up on the track. My buddies 92 f-body with a 434 gained 2 tenths when locked up at 90mph.[/Q