700R4 transmission in a HMMWV

[TOBASH]

I’m happy with the rebuilt 765R4.

I wanted to “Make Automatics Great Again”. So far it’s a home run.

 

[Subaugusta710]

Hi Guys, I’m swapping 700r4 for TH400 and getting ready to order the torque converter lock-up circuit. Do I need the dual brake switch to drop out the lock-up? If so, what switch is recommended? Also… could use some advice on how to configure the TV cable and shift linkage. I’m in a 1986 M998 that I’m converting from stock. Thanks!

 

[Mogman]

Hi Guys, I’m swapping 700r4 for TH400 and getting ready to order the torque converter lock-up circuit. Do I need the dual brake switch to drop out the lock-up? If so, what switch is recommended? Also… could use some advice on how to configure the TV cable and shift linkage. I’m in a 1986 M998 that I’m converting from stock. Thanks!

Have the transmission built with a 4th gear pressure switch in the valve body, then just wire up the torque converter solenoid to that switch, it will only go into lockup in 4th gear, nothing else needs to be switched, this can also be done after the transmission is built all you have to do is tap the 4th gear servo cover and put a switch in it.
EDIT, the 4th gear servo cover is the round thing on the right side of the transmission.

Of course you want to remove the cover, there is just a wire ring holding it in, you would have to depress it a little to get the ring out, there is a spring against that cover.

 

[Glider]

Bowtie overdrives has a tv cable that will work.

 

[Milcommoguy]

Have the transmission built with a 4th gear pressure switch in the valve body, then just wire up the torque converter solenoid to that switch, it will only go into lockup in 4th gear, nothing else needs to be switched, this can also be done after the transmission is built all you have to do is tap the 4th gear servo cover and put a switch in it.
EDIT, the 4th gear servo cover is the round thing on the right side of the transmission.
View attachment 880488

Not a whizz at transmissions... BUT how are the tranny swapper (that reads wrong) dealing with the TC lock-up solenoid / coil voltage requirements?

Are they hitting it with 12 Volts (tapped battery) or slamming it with 24 Volts. Like is there a 24 Volt coil or who cares or dropping resistor / proper wattage?

Just at the keyboard and bored.

Now I gota wizz, LOL, CAMO

 

[TOBASH]

Bowtie overdrives has a tv cable that will work.

it requires some modification, specifically dragging a round hole to oval to make it fit/mount properly.

 

[Subaugusta710]

I believe I asked them to include the solenoid. It has the 4 pin connector. So I should be good to go once I install the lockup circuit? I already wired a 24v to 12v converter in the truck. 15 amp fused circuit.

 

[Mogman]

All transmissions (that we would be talking about) are 12V even the 4L80 they put in the HMMWV,
They should have given you a schematic, all you have to do is wire 12V through the pressure switch to the lockup solenoid, unless they did that for you inside the transmission, again they should have given you that information.

 

[Mogman]

The 700R4 I was building before I decided to go 6L80 had pressure switches on 3rd and 4th gear so it would lock up in 3rd and 4th

 

[Subaugusta710]

Update: the 700R4 is installed but not yet complete. The shop I used did most of the work. I need to finish shifter linkage, and run 12v signal to trans for brake switch. I did drive it about 50 miles on the interstate manually shifting. My recorded top speed was 75mph. It will run 70mph but struggles on inclines. I'll have more info when the small bits sorted. I do not have a tachometer.

I'm wrapping up my 700r4 conversion and am struggling to come up with an easy adapter for the shifter linkage. Do you happen to have any photos of your linkage that you built? Would appreciate your advice. I really don't want to pay $$$ for the 4 speed shifter... at least not right now. Thanks

 

[gafuller01]

Just figured I would add to this thread, I built a clocking ring, this allows the NP218 to be coupled directly to the original 700R4 transfer case adapter at the correct angle, a 27 spline input gear must be installed in the transfer case, it also uses the stock 27 spline transmission output shaft,, I started with a "blank" clocking ring which already had the holes drilled and countersunk for the transfer case mounting holes, gear and ring cost me well under $100.00View attachment 796949View attachment 796950View attachment 796952View attachment 796953
View attachment 796949View attachment 796950View attachment 796952View attachment 796953

Do you happen to know whether this would also work for bolting a 700R4 and NP242 together? Where did you get the 27 spline input shaft for your transfer case? Who sells the blank clocking ring?
Thanks

 

[Mogman]

Do you happen to know whether this would also work for bolting a 700R4 and NP242 together? Where did you get the 27 spline input shaft for your transfer case? Who sells the blank clocking ring?
Thanks

No, the 242 does not have that input shaft available as far as I know, but there were several different renditions of the 242 so I would think it might be possible, with the absence of a clocking ring it is a rather moot point unless you want to build one from scratch as I did, I actually ended up using it on the 6L80 conversion as the ring would be the same for ether setup.
I am also moving this to a more appropriate forum now that it has been bumped.

 

[TenTires]

You can adapt your old bracket with a file so that the square cable end fits in the old round hole. Just hand file it or use a dremel. It can be done just give it a look.

Are you suggesting......putting a square peg.....in a round hole?? Sorry for reviving a reply from the dead just to say that. Couldn't help myself.