700r4 Question - Pirate4x4.Com : 4x4 and Off-Road Forum

MarkF · 10-25-2001, 10:55 AM

I just finished bolting in a 700r4 behind a SB350 in my Jeep CJ. I haven't done anything with the electrical connection for the tranny. Is it still safe to drive around like that (short term)? Or will I kill the tranny? I'm under the impression that the only thing the electric does is lockup the TC. Is that correct? So w/o I'd be driving with overdrive off. Am I way off?

Thanks
Mark F

Shaker · 10-25-2001, 04:19 PM

Yes you are correct you can drive but you wont have "overdrive".... <IMG SRC="smilies/beer.gif" border="0"> <IMG SRC="smilies/beer.gif" border="0">

orbitcat · 10-25-2001, 07:07 PM

I may be way off, and I'm still learning about the one I'm swapping in, but ...

I thought it would still kick into overdrive, but just the TC won't lock up. Whenever I drive a GM product with the 700-R4 in it, it seems to go into overdrive and then lockup a second or two after that. You can tell because when it kicks into overdrive, the RPMs are at 2000 (arbitrary) and then it drops to about 1700 when the TC locks up. You can tap the brakes and the rpms will climb up briefly when it unlocks, but it will stay in overdrive and relock if you are not accelerating.

Please let me know if I'm wrong on this. (nicely!)

orangefj45 · 10-25-2001, 08:19 PM

the 700 series transmissions are designed to go into lockup above roughly 43 mph in 3rd and 4th gear, as long as some other conditions are met. lockup is also controlled by braking, vacuum and amount of throttle being applied. the trans will shift into overdrive without the lockup harness being plugged in. lockup is purely a function of the torque converter.
driving the rig around for a while will not do any damage but you should get the lockup wiring working when you get a chance.
the biggest killer for trannies is heat. the hottest part of any trans is the torque converter. but, when the converter goes into lockup, all the slippage is eliminated and therefore does not produce any more heat.
make sense:?!
<IMG SRC="smilies/confused.gif" border="0"> <IMG SRC="smilies/confused.gif" border="0"> <IMG SRC="smilies/confused.gif" border="0">

10-25-2001, 10:55 AM	#1 (permalink)
MarkF Registered User Join Date: Jul 2001 Member # 5661 Location: West Hempstead, LI Posts: 57	700r4 Question I just finished bolting in a 700r4 behind a SB350 in my Jeep CJ. I haven't done anything with the electrical connection for the tranny. Is it still safe to drive around like that (short term)? Or will I kill the tranny? I'm under the impression that the only thing the electric does is lockup the TC. Is that correct? So w/o I'd be driving with overdrive off. Am I way off? Thanks Mark F __________________ 98 TJ 4.5" RE LA, 35" lots of armor

10-25-2001, 04:19 PM	#2 (permalink)
Shaker Zeus of the Sluice Join Date: Mar 2001 Member # 3694 Location: Chesapeake, VA, USA Posts: 3,584	Yes you are correct you can drive but you wont have "overdrive".... <IMG SRC="smilies/beer.gif" border="0"> <IMG SRC="smilies/beer.gif" border="0"> __________________ Need Steering? www.shakerbuilt.com Too Many Projects not enough Time...

10-25-2001, 07:07 PM	#3 (permalink)
orbitcat Registered User Join Date: Jul 2001 Member # 5801 Location: Denair, CA Posts: 629	I may be way off, and I'm still learning about the one I'm swapping in, but ... I thought it would still kick into overdrive, but just the TC won't lock up. Whenever I drive a GM product with the 700-R4 in it, it seems to go into overdrive and then lockup a second or two after that. You can tell because when it kicks into overdrive, the RPMs are at 2000 (arbitrary) and then it drops to about 1700 when the TC locks up. You can tap the brakes and the rpms will climb up briefly when it unlocks, but it will stay in overdrive and relock if you are not accelerating. Please let me know if I'm wrong on this. (nicely!) __________________ Life is so much better now!

10-25-2001, 08:19 PM	#4 (permalink)
orangefj45 Registered User Join Date: Aug 2001 Member # 6816 Location: Fawk if I know Posts: 15,280	the 700 series transmissions are designed to go into lockup above roughly 43 mph in 3rd and 4th gear, as long as some other conditions are met. lockup is also controlled by braking, vacuum and amount of throttle being applied. the trans will shift into overdrive without the lockup harness being plugged in. lockup is purely a function of the torque converter. driving the rig around for a while will not do any damage but you should get the lockup wiring working when you get a chance. the biggest killer for trannies is heat. the hottest part of any trans is the torque converter. but, when the converter goes into lockup, all the slippage is eliminated and therefore does not produce any more heat. make sense:?! <IMG SRC="smilies/confused.gif" border="0"> <IMG SRC="smilies/confused.gif" border="0"> <IMG SRC="smilies/confused.gif" border="0"> __________________ Maybe you outta stick to legos!

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode