700R4 With No Lockup?

[BigRed76]

I just purchased a '71 chevy c10 that the PO installed a 700R4 trans in. It has the TV cable connected with a home-made looking cable bracket, and the converter lockup wiring is not hooked up. Is it safe to drive the truck in overdrive with no converter lockup? Either way I'm going to be wiring up the converter lockup in the future, but I'm just curious about this.

[Wrenchbender Ret]

When I bought the first one, the trans. shop said it was OK to run it without the lockup. I had it in a 63 with a 454 engine & ran it about a year that way before I put a lockout kit on it. I had no problem but the lockup gives it another demention. The main thing is to get the cable correct.

[jayman68]

Originally Posted by Wrenchbender Ret

The main thing is to get the cable correct.

here is a link to a very helpful step by step on making sure the TV is adjusted properly.

http://www.maddogtransmissions.com/v.../tv_cables.pdf

[storm9c1]

It won't hurt anything by not using the lock-up.........except maybe your wallet at the gas pump. And a little extra heat generated by the converter while cruising on the highway. Back in the day, that's exactly how non-lockup 3-speeds worked all day long.

[clinebarger]

The converter "needs" to be locked up when in 4th gear. The planetary lube curcuit is cut to almost nothing when in 4th without the converter locked. Dont drive on long freeway trips in 4th.

When running a "non-lock up converter" in a 700R4.....You have to install a "Lube Valve" in the pump to correct the lube curcuit. This REQUIRES a non-lock up converter, The stock converter will not work.

The lock up is easy to hook-up with a dual brake switch, wire, pan gasket & some ATF, Search this forum, Ive posted on this subject alot.

Untill you do something run it in 3rd, Driving on long freeway trips in 4th WILL burn your planetaries down. I couldnt count the "Blue" gear sets ive seen from being overheated

[storm9c1]

Great info. I stand corrected. I never knew about the planetary lube circuit on lockup. Still learning something new everyday.

[Wrenchbender Ret]

I stand corrected also. I use a vacuum switch from a late 80's van. I have it hooked to ported vacuum on the carb. It releases the lockup on hard accel. & decel. Will this harm the 4th gear?
George

[jfortvalley]

IT wont harm 4th , 4th gear is hydraulic and as long as the cable and transmission are in good shape you should be good .

[BigRed76]

So to wire up the lockup all I need to do is get the vacuum switch and run my wires from there to the transmission?
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[gysgtc]

I just had my 700 tranny rebuilt and all I have to hook up is the tv cable and a key on power wire to the tranny. No more switch on the brake pedal.

[made2drag]

Originally Posted by clinebarger

The converter "needs" to be locked up when in 4th gear. The planetary lube curcuit is cut to almost nothing when in 4th without the converter locked. Dont drive on long freeway trips in 4th.

When running a "non-lock up converter" in a 700R4.....You have to install a "Lube Valve" in the pump to correct the lube curcuit. This REQUIRES a non-lock up converter, The stock converter will not work.

The lock up is easy to hook-up with a dual brake switch, wire, pan gasket & some ATF, Search this forum, Ive posted on this subject alot.

Untill you do something run it in 3rd, Driving on long freeway trips in 4th WILL burn your planetaries down. I couldnt count the "Blue" gear sets ive seen from being overheated

Running a 700r4 in 3rd is safe right? Mine didn't have any wiring going to the 4 pin connector and I don't know how long it has been driving that way.

[YoungPup1977]

why not try to fix your trans issue instead of driving it and hoping it may last that next mile......most likely GM did not design the 700R4 to be driven in 3rd all the time...Good Luck.

When you say no wiring to connecter, you mean no wiring on the outside of the transmission correct ?

[made2drag]

Originally Posted by YoungPup1977

why not try to fix your trans issue instead of driving it and hoping it may last that next mile......most likely GM did not design the 700R4 to be driven in 3rd all the time...Good Luck.

When you say no wiring to connecter, you mean no wiring on the outside of the transmission correct ?

no factory harnes

[made2drag]

just want to drive this thing and not interested in fixing 4th right now, just want to know if I can safely drive this in 3rd.

[YoungPup1977]

Good Luck....




QQ.....

[made2drag]

Thanks, but I don't do this for a living and not willing to experiment on something that still works and is good enough for me.

[GASoline71]

Fixing it to work properly isn't experimenting. I wouldn't drive it around only using 3rd if it was me. If that was the case I'd just install a TH350.

Reread post #5 in this thread and then decide for yourself if you should not hook up the lockup...

Gary

[made2drag]

Originally Posted by GASoline71

Fixing it to work properly isn't experimenting. I wouldn't drive it around only using 3rd if it was me. If that was the case I'd just install a TH350.

Reread post #5 in this thread and then decide for yourself if you should not hook up the lockup...

Gary

Sounds like you should re-read post 5.

[made2drag]

Originally Posted by GASoline71

Fixing it to work properly isn't experimenting. I wouldn't drive it around only using 3rd if it was me. If that was the case I'd just install a TH350.

Reread post #5 in this thread and then decide for yourself if you should not hook up the lockup...

Gary

How would you fix it? How do you get it to shift in 4th? TV cable is right and dipstick level is full in park, checked hot after a 15 min drive. Give me a straight forward one and done answer. Then tell me why my solenoid clicked once and never again while I gave pin "a" 12 volts and pin "d" chassis ground and my 10 amp fuse didn't blow. Or are you talking about sending this off to a trans shop so they will ask me for $1000 to rebuild it? Transmission shops wont spend hours checking and tinkering because they cant afford a bad rep if it tears up a week later. Dropping a pan and fiddling with a 35 year old transmission isn't an option for me. Anything over $400 in labor and parts is a waste of time and money on a 35 year old transmission with who knows how many miles and who knows who did what to. The question is: Can I drive it in 3rd, since 4th without a lockup will burn it up. 4th ain't working and lockup needs fixed. It appears from how nasty and gunked up the connector was that the connector hasn't been used in decades.

[made2drag]

...................1st....2nd...3rd...4th

Powerglide....1.76 1.00
TH350..........2.52 1.52 1.00
TH400..........2.48 1.48 1.00
200r4...........2.74 1.57 1.00 0.67
700r4...........3.06 1.62 1.00 0.70

People drive in 3rd all the time...towing and mountain driving and track.... if a "4th gear lockup only" kit is offered, im assuming 3rd gear gets the lubrication it needs and there isn't the TC spin that causes excess heat like in 4th. The whole reason for lockup in 4th is to clamp the TC to keep from spinning and also open up lubrication to the planetary gears. 3rd doesn't need lockup, so i'll be fine. So the answer must be YES, it's ok to drive it in 3rd and avoid $500-$1000 to fix this 700r4, to let me save $5 at the pump. BTW, I love my th350 in my other truck and wish this was a th350 too.

[Bigdav160]

I thought I responded to one of your transmission conversations but maybe not.

You can run the 700R4/4L60 in third forever. In third there is really no reason to lock the converter clutch.

If your 700R4 has good second and good third, there are very few reasons why there wouldn't be a 3-4 shift. Usually, governor valve or 3-4 shift valve line up in the valve body.

Your broadcast code began with a "Y"? That wasn't originally a truck transmission so it was from a fuel injected ECM controlled converter clutch vehicle.

IIRC, power from brake switch into A, ground to energize solenoid on D and 4th gear input to ECM on B

[made2drag]

Originally Posted by Bigdav160

I thought I responded to one of your transmission conversations but maybe not.

You can run the 700R4/4L60 in third forever. In third there is really no reason to lock the converter clutch.

If your 700R4 has good second and good third, there are very few reasons why there wouldn't be a 3-4 shift. Usually, governor valve or 3-4 shift valve line up in the valve body.

Your broadcast code began with a "Y"? That wasn't originally a truck transmission so it was from a fuel injected ECM controlled converter clutch vehicle.

IIRC, power from brake switch into A, ground to energize solenoid on D and 4th gear input to ECM on B

Finally! Thank you so much, I would have never figured that out! Yes, its a "Y". It's an 1986 with 6YKM-Y-00258537 serial which is similar to a 87 serial. That just made my day! I'll definitely look into this! Thanks!!!

[made2drag]

Originally Posted by Bigdav160

I thought I responded to one of your transmission conversations but maybe not.

You can run the 700R4/4L60 in third forever. In third there is really no reason to lock the converter clutch.

If your 700R4 has good second and good third, there are very few reasons why there wouldn't be a 3-4 shift. Usually, governor valve or 3-4 shift valve line up in the valve body.

Your broadcast code began with a "Y"? That wasn't originally a truck transmission so it was from a fuel injected ECM controlled converter clutch vehicle.

IIRC, power from brake switch into A, ground to energize solenoid on D and 4th gear input to ECM on B

So pin "b" is responsible for 4th to engage or is 4th gear sending input signal to ecm? Without pin "b" connected 4th wont activate? The manual I had said it came out of a 86 GM wagon b body. If I can get 4th to start working, I will see why my 12v on "a" and grnd on "d" doesn't make solenoid click anymore. Changing the solenoid doesn't look hard. I thought 4th was hydraulic and didn't need any electronics to work.

[Bigdav160]

All shifts including Fourth gear are hydraulic. Sometimes the weighted head comes loose on the governor and the valve will not have enough travel. It will not shift past 3rd. Not too hard to remove and check.

Lockup is different and electrically controlled through the TCC solenoid. Yes, on fuel injected models the 4th gear pressure switch tells the ECM when the trans has shifted to 4th and the ECM then grounds D to lock up the clutch.

My experience is the TCC solenoid has very little to no noise when energized.

[made2drag]

Originally Posted by Bigdav160

All shifts including Fourth gear are hydraulic. Sometimes the weighted head comes loose on the governor and the valve will not have enough travel. It will not shift past 3rd. Not too hard to remove and check.

Lockup is different and electrically controlled through the TCC solenoid. Yes, on fuel injected models the 4th gear pressure switch tells the ECM when the trans has shifted to 4th and the ECM then grounds D to lock up the clutch.

My experience is the TCC solenoid has very little to no noise when energized.

Awesome! That helps me tremendously! And exactly the info im looking for! I really appreaciate it. So in my case I ran a fused 12v to my pressure switch and the other side of that switch I went to pin "a" and pin "d" is always grounded. I have mine wired to have 12v on pressure switch and when 4th gear pressure gets high enough it makes the connection and the 12v goes to pin "a". So what is it I need to tie Pin "b" to? I heard a faint click when I put 12 volts on pin "a" for a second and I did it again but it didn't click.