Manually locking up the torque converter

Has anyone ever done something like thing on our A750 trans? How well does this tranny respond to this?

I've been researching valve body upgrades and came across a company called West Coast Cruisers. They sell a "kit" that with a flip of a switch will lock up/keep the torque converter locked up, but they want over $200. http://www.westcoastcruisers.com/transfer.php

I think I have figured the wiring out for this, just need me a relay.

I figure this would really help towing and goin slow down hill.

 

what are the benefits of this? and are the potential benefits worth 200 bucks?

 

My thinking is:
-Less heat build up from the torque converter, especially when going slow and loaded up.
-Can control down hill speed, like a manual, better


I wouldn't buy the "kit". I would do it my self for like $30

I'm just wondering if anyone has done this and if anyone thinks there would be adverse effects?

I know on the older dodge diesel auto, you had to do this kind of mod unless you wanted to replace the tranny all the time.

 

That kit looks like a $5 rocker switch wired to a $3 relay...


Interested to hear more about the principle. It would help with gas mileage too I would think. (highway)

 

exactly.

I just wonder if anyone here has done it. I've been searching other forums (IH8MUD, TTORA, XRU, and here), but have come up with nada.

 

U think their would be any adverse effects?

 

so this would lock the transmission into one gear and not let it shift? that has the potential to be awesome...

 

No, just so it "acts" like a manual in a sense. It locks the converter so that it will not do partal shifts, it will stil shift.

 

well our downhill assist BS is practically the same thing. i actually think its obnoxious when i tap my brakes going downhill and it shifts down on me instead of coasting.

 

I can see there some if its used incorrectly, but my intensions are going down hill and towing, except for starts.

 

But this has the potential to acctually slow the truck down, unlike now where it may down shift but unlocked which does not slow it much, just builds a lot of heat (I think). I'll be installing my tranny temp gauge this week and I'll check on the temps.

 

could you just leave it locked all the time?

 

I don't think so, cause from starts or coming to a stop, I think it would stall.

 

Slow and loaded up, the TCC is not locked anyways.
Depends on the vehicle, but most will only lock in direct and overdrive... some of the 5 and 6 speeds will lock in 3rd or 4th, but under any moderate load at all, it unlocks.
Locking under those conditions is going to be hard on the driveline.

Downhill speed control is a benefit, but the 2nd Gen system is already pretty tight... I don't think the TCC is unlocking.

 

With going slow, ya the tc is not locked thus creating a lot of heat.


I don't believe that the tc is ever locked with down shifting to control down hill speed.

But I think I might tackle this this weekend. I'll update this as I learn more about it.

 

The transfer case input shaft on the auto is MUCH smaller than the input shaft used in the manual transmission. Obviously they were anticipating much lower shock loads with the juice tranny. If you defeat that, the result could be a broken shaft.

Look here below where it says "updated information" in red: http://www.tacomaworld.com/forum/2nd-gen-tacomas/131275-inside-05-tacoma-t-case.html

 

Thought they were the same size?

Not really worried about it, plenty of supercharged 4x4 pushing 350+.

 

Having the torque converter lock and unlock manually is a BAD idea. The only people that really need them are the diesel crowd and the drag racers. The converter locks up at 30-40 mph anyways and stays locked up until you either A. Tap the breaks. B. slow down. There is absolutely no reason for this at all unless you are doing trailer pull competition or getting ready to run a 10.68 in a 1/4 mile. It is way better on gas milage, and the engineers design them to 1. Last for a long time, and 2. Allow for the maximum gas milage possible out of the vehicle. Don't mess with the tranny! Trust me, I was a trans tech for years for GM and there where very limited thing that you needed to do on a 4l60e to make it last longer and a little more efficient.