700R4, Is it necessary to lockup the Torq Conv?

[ck5566]

Will the trans work just fine in my 68 C10 w/o any lockup TC kit? Or is it **NECESSARY** to have some kind of TC lockup kit? And if one is used how much of a difference will it really make/ MPG /cooler/longer life? The truck WONT be used for Construction uses/heavy loads or long trips (2-5 hrs) steady driving on the highways (may be once in a while), just for every day "O" I need a truck for this or that you know those necessary times a truck is needed. thanks in advance

[Rod Run]

My transmission builder said they aren't necessary and don't prevent any type of damage. Strictly a fuel economy type of thing. He thinks the returns on investment are worth it though

[ck5566]

Originally Posted by Rod Run

My transmission builder said they aren't necessary and don't prevent any type of damage. Strictly a fuel economy type of thing. He thinks the returns on investment are worth it though

I have seen these kits starting under $100 & going well past $300+. Whats the one most people use that is a good kit and not so difficult to install and that wont break the Bank, or in this case do you get what you pay for type of thing

[Rod Run]

What my guy did for me, is where the wiring plugs into the transmission, he wired it and marked the plug with a '+' and a '-' sign.

Now all I have to do is spend about $5.00 on a switch, mount it somewhere in my cab (probably around my light switch area) and hook the positive to positive and negative to ground. I'll connect the negative from my transmission to a bolt on my bellhousing (because that will be the easiest) for a ground.

When I'm driving down the highway and reach a good cruising speed, I'll just flick the switch and lock up my converter for the good gas mileage. When I was some umph in my pedal, I'll just flick the switch off. He said he's been doing them this way for over 20 years now in all his toys and many customers cars (even with huge horsepower) and never had one problem with it.

Having to buy and flick a simple switch and a few feet of wire was a lot better/cheaper choice for me, than spending big money on someone's "kit" and the extra work involved to install it.

[sawyerrm]

Originally Posted by ck5566

I have seen these kits starting under $100 & going well past $300+. Whats the one most people use that is a good kit and not so difficult to install and that wont break the Bank, or in this case do you get what you pay for type of thing

I had this in my El Camino, you could switch it on and off as you pleased. Same idea as suggested by Rod Run. It worked ok, of course I only got 9 mpg so economy wasn't really a factor

[rowdy350]

I drove mine for almost a year without the lock up. 2 months ago I bought a new cable and the lock up kit from BOWLER Transmission. I am MUCH MUCH happier now. I should have done it right away.

[Bigdav160]

Put a trans fluid temp gauge in it and find out.

The lockup function is to prevent the fluid from overheating while in OD. Enough load, enough head wind/speed and the fluid can boil right in the converter.

[CUSTOM/10]

I have a 700R4 in my truck but haven't gotten it running yet, but from what I've read the manual switch lock-up isn't a good idea. If you have it locked and you have a panic stop situation, and slam on the brakes you stall the engine and loose all power & power assisted functions, ie: power steering, power brakes !!!
You should have a brake pedal release for the lock-up.

I have no 1st hand experience just read this .

Gary

[67swb72klb]

Originally Posted by CUSTOM/10

I have a 700R4 in my truck but haven't gotten it running yet, but from what I've read the manual switch lock-up isn't a good idea. If you have it locked and you have a panic stop situation, and slam on the brakes you stall the engine and loose all power & power assisted functions, ie: power steering, power brakes !!!
You should have a brake pedal release for the lock-up.

I have no 1st hand experience just read this .

Gary

Exactly right. You can get the brake light switch from a square body truck it has the extra terminals for the trans

[davepl]

Not necessary. I considered adding it to my 200-4R when I had to replace the converter but when I pulled the pan to look, there wasn't even a TCC or internal harness inside the trans at all!

Probably worth it for mileage but transmissions don't slip that much at speed just because of the way torque converters work. With the overdrive, however, you might be bringing the RPMs down enough that it does start to slip.

Put another way, without the overdrive you wouldn't need it. With the overdrive it's a good idea, but still not needed.

[Dave in Ozark]

Originally Posted by 67swb72klb

Exactly right. You can get the brake light switch from a square body truck it has the extra terminals for the trans

I just replaced the brake switch on my truck that has this transmission. I saw the option for the 4 terminal but got the direct replacement for the one I had. I was thinking about it the next morning and wished I had just got the one for the cruise control cancel (4 term) to kill +12 to the lockup switch

[Rod Run]

Originally Posted by CUSTOM/10

I have a 700R4 in my truck but haven't gotten it running yet, but from what I've read the manual switch lock-up isn't a good idea. If you have it locked and you have a panic stop situation, and slam on the brakes you stall the engine and loose all power & power assisted functions, ie: power steering, power brakes !!!
You should have a brake pedal release for the lock-up.

I have no 1st hand experience just read this .

Gary

Originally Posted by 67swb72klb

Exactly right. You can get the brake light switch from a square body truck it has the extra terminals for the trans

This is not "exactly right"

I had that question when my guy did my tranny. He said the car will be the same as trying to start off in a higher gear with a standard transmission.

After he told me that, I thought about it and it totally made sense to me. Then he took me for a ride in his car and showed me. I suppose anything is possible, if you have a weak running engine or a super-high stall, but my experience didn't show that problem at all.

[fwayne]

OK So you are placing a 4 speed transmission in your truck because you want that lower cruise RPM and mileage benefit right? So the Lock-up circuit is just as beneficial if not more so. You don't need a fancy computer or funny looking box. There are kits on the market to easily convert the 700r4 to a hydraulic lockup. Essentially using road speed to determine when lockup is needed. Adding lockup is much like adding a 5th gear. It reduces RPM even more, and stops the loss of the fluid coupling action of the torque converter. Then your efficiency improves much more over a no-lockup situation. As others stated, it reduces heat significantly. 700r4's got a bad rap in the 80's and this was due to several factors, but heat was one of them. Now we know how to make them strong and long-lasting. Running without lock-up isn't going to "hurt" but it certainly will have more drawbacks than a lock-up situation every time.

Don't think it makes a difference? Drive anything made since 1985, cruise at an even speed above 55. Leave the gas pedal at cruise position, but touch the brake pedal only enough to turn on the brake lights. This makes the lock-up turn off. Notice it feels like you dropped a gear and the rpm went up a noticeable amount. Thats the effect of Lock-up!

Google Hyrdaulic lockup kit for your transmission you'll see.

['68OrangeSunshine]

I used to run a '67 K/10 Suburban w/ 454/TH350/NP205/12-Bolt 3.73 posi. PO's rustic-engineering. It ran good on the straight and level, but in the hills, when I tried to downshift and use engine-braking, the TH350, would automatically upshift. Since it had drum brakes all around [and '67 4x4 front drums are rare parts], stopping was more a situation of selecting an alternative soft target.
Would Lock Up give me positive downshift engine-braking capability? I've thought of ressurecting this beast with a new engine and a 700-R4.