First, as we all know, the early, double-vane torque convertors are rather noisy when not locked. Some people have installed a switch to manually lock the t/c when idling in park or neutral.

What I am wondering is can the signal from the neutral safety switch be used to latch a relay, thus locking the t/c when in park or neutral?

Second, would having the t/c locked when in P or N cause any problems with the t/c or transmission?

 

Pikachu.

I have also been wondering about a toggle switch that I could use to manualy lock my converter too.

my question is do you or anyone know what wire I have to tap into on the tranny harness to lock it up, what color is it. and how hard is it to do???


Diesel rod

 

Find the 12 pin connector on the passenger side of the trans. Look for a purple with yellow trace wire, this is on pin 4. I used a t-tap connector to tie into the wire. Run a 16 gauge wire to a switch, hook the wire that you ran from the tranny to one side of the switch and a grounded wire to the other side. When you flip the switch you ground the T/C solenoid and the T/C locks, don't forget to unlock the converter or it will stall the engine.

Later,

AlanB

 

If you don't want to run as much wire you can find the purple wire with the yellow tracer in the harness under your master cylinder at the firewall. That is where I tapped into mine.

 

what is the advantage or reason for putting in this switch besides for noise? should i maybe do it to my 02

 

Here are some good instructions for the manual TC lock on a superduty.http://www.forgotton.net/mods/tclock/index.htm

 

I got my information to hook it up off the diesel innovations website, but it's the same as what has been posted. The biggest advantage I found for having the switch is I can use it as a mild engine brake. When slowing down to a stop ligh/sign, instead of the transmission dropping out of gear and coasting to the stop, with the TC locked up, the engine will keep slowing the truck down till I get there, then shut if back off quick before I kill the engine.

 

The TC lock mod is purely a TOWING mod.

For most ppl, it is used to lock the transmission to the engine while using an exhaust brake. *MOST* (but not all) ford computers will unlock the TC as soon as you tap the brake. So much for engine braking!

Anything below about 20mph and the TC lock is not needed for stopping. Just not enough engine revs, and you risk stalling the motor.

The other advantage to a manual TC lock is uphill, SLOW towing. If you cant get above the 45mph minimum lockup speed, and your tranny temps are climbing, hit the lock switch and that will help cut down on heat build up do to slippage.

Locking the TC in P and N is not a good idea.

If you have one of the "noisy, sounds like rocks inside a beer can" early torque convertors, you need to get it replaced, not lock the TC in park.

 

Why would we need to get it replaced?? It's not defective, just a different noise than the newer ones. It's a double disc TC compared to the new ones that are only a single disc, that is why they are quieter. At least that is what the transmission guy at the Ford dealership told me.

 

Its my understanding that the "rattling noise" you hear is a sign of a bad TC. If locking the TC makes the noise go away, then that confirms it.

Ford even has a TSB for it. That noise is caused by an "Impact of the clutch piston and the cover spline teeth".

 

So if you have an old SD like mine and Farmb0y, what would be the incentive to change it, besides the noise going away? Does this condition create other problems in the long run? My warrantee's been out for a little while now... Anyone change theirs, what was the cost?

 

Well, an impact implies two objects that shouldnt be touching. Most likely over time it will allow particles to float around in your tranny fluid that could cause/create additional wear on other parts. Basically a slow mechanical meltdown.

If you change your fluid and have a fluid filter, then you might get some more life out of it, but over-all, its my understanding that it will eventually cause tranny failure.

These ford trannies arent known for being bullet proof to begin with.

As for just replacing the TC, I know some guys are installing the new torqueshift TC into the older 4r100 trannies. Its a tight fit, but they are making it work. I dont know all the details on that swap tho.

 

Good input, any other takes or experiences with replacing the TC for this reason? Still interested to find how much to replace stock TC. Thanx

 

Hey everyone. Once my TC locks up, it stays locked in any gear regardless if I press the brake or not unitl just about 1000 RPMs. From what I have read this is basically a good thing, or would I benefit from installing a lock switch?? Actually I have only tried it with and without the overdrive. I havent really downshifted into second to see if it stays locked, I just assume it will.

 

Sounds like your one of the lucky few who have the PMT* code on the computer. It will not unlock the TC when you hit the brake pedal. I wouldnt mess with the TC lock with your code.