? about my 700R4 swap

[cbrodine]

I'm swapping in a 1991 700R4 in place of the 4 speed that originally came in my 73 GMC C25...I thought I had everything but wondered if I HAVE to also get a converter lock up controller, like this...

http://www.summitracing.com/parts/bmm-70244/overview/

Do I have to have one of these also for my swap?

 

[oopsman_09]

you could run it without lockup but it would be nice for highway mileage. there is a way to do it with an oil pressure switch so it locks in overdrive that is way cheaper than a controller if your ok with minor wiring. and if your ok using a toggle to turn it off for slow city driving.

 

[HotRodPC]

Yep, you could do a manual push button lock up for highway driving if you wanted. Just be sure to install a lock up cancel to the brake light switch so it cancels itself.

or

You could get an OEM Vac Switch from an OEM 700r4 Truck and the wiring harness from the firewall mounted Vac Switch to the lock up plug on the trans. The trans should be pre wired internally to the 3 and 4th gear pressure switches to only allow lock up in 3rd or 4th. I myself like the OEM methods better than the aftermarket stuff that is expensive.

What are you doing about your speedo? If this is a 91 700r4, then it's got the reluctor wheel output shaft for the electronic speedo.

 

[cbrodine]

Yep, you could do a manual push button lock up for highway driving if you wanted. Just be sure to install a lock up cancel to the brake light switch so it cancels itself.

or

You could get an OEM Vac Switch from an OEM 700r4 Truck and the wiring harness from the firewall mounted Vac Switch to the lock up plug on the trans. The trans should be pre wired internally to the 3 and 4th gear pressure switches to only allow lock up in 3rd or 4th. I myself like the OEM methods better than the aftermarket stuff that is expensive.

What are you doing about your speedo? If this is a 91 700r4, then it's got the reluctor wheel output shaft for the electronic speedo.

SOB!!! I didnt think about the speedo being electronic...Not sure what to do about that.

 

[bucket]

IIRC, you can get the speedo gears from any 700r4 and simply put them in place of the VSS setup.

And if you don't run the converter locked up at highway speeds, you WILL fry the trans after a little while. Even if you just rig up a toggle switch to lock it, it will be better than nothing. I'd also highly recommend a trans temp gauge, every 700r4 should have one.

 

[cbrodine]

IIRC, you can get the speedo gears from any 700r4 and simply put them in place of the VSS setup.

And if you don't run the converter locked up at highway speeds, you WILL fry the trans after a little while. Even if you just rig up a toggle switch to lock it, it will be better than nothing. I'd also highly recommend a trans temp gauge, every 700r4 should have one.

Yep, yep! I am getting a lockup kit from Monster Transmission, I'll also be getting a trans temp gauge too!
Thanks for the responses!

 

[HotRodPC]

IIRC, you can get the speedo gears from any 700r4 and simply put them in place of the VSS setup.

And if you don't run the converter locked up at highway speeds, you WILL fry the trans after a little while. Even if you just rig up a toggle switch to lock it, it will be better than nothing. I'd also highly recommend a trans temp gauge, every 700r4 should have one.

Is it that easy? The 700r4's I built were in 4x4's or old enough they didn't have the reluctor wheel, so I've not had to deal with that. Is it as easy as removing the wheel and installing a gear? It would be nice if it's true.

Now on TCases, I'm almost certain it's not that easy. I think the output shafts are totally different.

 

[bucket]

Is it that easy? The 700r4's I built were in 4x4's or old enough they didn't have the reluctor wheel, so I've not had to deal with that. Is it as easy as removing the wheel and installing a gear? It would be nice if it's true.

Now on TCases, I'm almost certain it's not that easy. I think the output shafts are totally different.

From what I remember, it was that easy. It's been about 10 years though.