700R4 transmission in a HMMWV

[Glider]

Bowtie did not supply a pig tail. I ordered one and they sent a wiring diagram for the trans But I really don't understand it. I plan on calling them Monday for a clarification unless someone could tell me what to wire to where. I also ordered a 24 to 12 V step down converter good for 40 amps and a 24 V and Dual brake switch. Wiring diagram attached

 

[Mogman]

Bowtie did not supply a pig tail. I ordered one and they sent a wiring diagram for the trans But I really don't understand it. I plan on calling them Monday for a clarification unless someone could tell me what to wire to where. I also ordered a 24 to 12 V step down converter good for 40 amps and a 24 V and Dual brake switch. Wiring diagram attached

All you have to do is supply 12V to A, should be through a switch (and a fuse of course) in case you want to disable the TC lockup, if you do not have 12V to A then your trans is not going into TC lockup and you are causing the trans to heat up unnecessarily.

The temp switch is open and inhibits TC lockup until the transmission comes up to a reasonable temperature (it will heat up faster without TC lockup)

The 4CL switch is the 4th gear pressure switch that automatically puts the trans. in TC lockup in 4th gear

The connection D ECM ground can be used to FORCE TC lockup by running it through a switch to ground, should be used VERY carefully as if grounded the engine will stall if you stop but could be useful is for example you were going a long way in a manually selected lower gear and you wanted to reduce trans heat up.

The "sig to computer" looks like B is only useful to tell the ECM (that you do not have) that the trans is up to temp.

The coil with the diode across it is the TC lockup valve

The 12V to A does not need to be switched by the IGN, as the only time it draws current is when in 4th gear or when D is grounded, of course it will not hurt to be switched, do you have a 200A alt??

 

[Glider]

Looking at the the shifter linkage. Stock was a rod bent in the shape of a U. Does anyone have a picture handy of what we know works? I'll make new from threaded rod I guess. Looks like it needs to be longer. Any suggestions would be great.

Mogman, I'm going to attempt drawing a schematic and post for all to review

 

[Mogman]

Looking at the the shifter linkage. Stock was a rod bent in the shape of a U. Does anyone have a picture handy of what we know works? I'll make new from threaded rod I guess. Looks like it needs to be longer. Any suggestions would be great.

Mogman, I'm going to attempt drawing a schematic and post for all to review

This is how I did the 6L80, not sure if the bolt pattern will allow this or not, it is the same as a 4L80 as that is the bell crank from a HMMWV with a 4 speed.
The U shaped rod should also work just make it out of all thread the length you need.

 

[Glider]

I bought that exact part when I was thinking I would go the 6l80 route. Do you remember the rod size/thread pitch?

What are the parts called the rod screws into?

 

[Mogman]

It is all 3/8-16

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I had to do some mods to clear the drive shaft, of course I have no idea what you will face if you go this route.

 

[Glider]

It is all 3/8-16

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I had to do some mods to clear the drive shaft, of course I have no idea what you will face if you go this route.

Thank you!

 

[Glider]

Threaded rod in hand.

Wiring diagram submitted to experts for approval! Thank you in advance

 

[Mogman]

You can ground it to the engine or transmission, curious did the trans builder specify a brake switch?
It seems unnecessary as the transmission will only go into lockup in 4th gear but would possibly be specified for CYA safety reasons.
You need to power the converter from a switched source or it will drain the batteries, you could tap off of the 5A wire at the alt and make sure you put a fuse in-line wherever you tap the switched power.
I would put a switch in-line with the brake switch so you could disable the lockup, it could be handy pulling a hill for example it would give you a "lower" gear in between 4th lockup and 3rd gear'

 

[Glider]

Update on the swap. The trans had to come back out and be re-rebuilt. I drove the HMMWV less than 100 miles. Reverse started slipping. Felt literally like a badly slipping manual clutch. When you selected reverse it would barely make a shifting noise and barely move. I talked to Bowtie initially and they wanted us to provide line pressures and some other things for diagnosis which we did. After that they wanted me to return the trans to them for repair. Shipping would have been at least 600-700 round trip, then add the local shop charge for removal and another installation, and the time involved in shipping across country, we decided to repair ourselves and see what Bowtie could do to help on their end. Removal and inspection showed what my trans installer said to be a very rare problem. Apparently, the piston that engaged the reverse clutches was bad or incorrectly installed. This let to the reverse clutches being burned. Everything else in the trans was fine, but since the installer was technically rebuilding the trans and giving me a 3 year warranty he replaced all the clutches,etc. with his parts. We have had conference call with Bowtie yesterday. I am waiting to see today if they are willing to help out with any of the expenses.

So...with all that said thrans is back in and works great. I still need to hook up the brake switch for the converter lockup. I bought a dual pole brake switch from a HMMWV with 4L80. The switch technically works but when I adjust the brake properly the pole for cancelling convertr lockup does not activate unless the brake lever is pushed so far the brakes would be locked. I cant find any adjustment on the switch. https://www.ebay.com/itm/1745428314...mwwAEVOaPfEXYMshEwNuidvwjslyVCGhoC2dgQAvD_BwE

I'm getting frustrated with all that has happened and hoping to get some help without being told to use the search function. I have now decided to use a 24v relay tied to the standard brake switch to supply 12v to trans. My questions:

What wire can I splice into either under the hood or under the body to get a brake signal. Is there possibly a connection that I could simply us a "Y" packard adapter for the 24 volt signal. A "plug and play"location with an adapter I can make myself. I feel like I have the 12v side sorted.

Given that I am now going to use a relay. I thought about tying in the downshift/fan cutoff switch that is already installed on injector pump to disengage the torque converter when going wide open throttle. It seems like a good idea that yes it would work when going WOT but would also turn off fan everytime i hit the brake by backfeeding 24v. It would be great it that would work but can't figure out how to execute without negatives side effects.

As always any help appreciated.
Dan

 

[Mogman]

Update on the swap. The trans had to come back out and be re-rebuilt. I drove the HMMWV less than 100 miles. Reverse started slipping. Felt literally like a badly slipping manual clutch. When you selected reverse it would barely make a shifting noise and barely move. I talked to Bowtie initially and they wanted us to provide line pressures and some other things for diagnosis which we did. After that they wanted me to return the trans to them for repair. Shipping would have been at least 600-700 round trip, then add the local shop charge for removal and another installation, and the time involved in shipping across country, we decided to repair ourselves and see what Bowtie could do to help on their end. Removal and inspection showed what my trans installer said to be a very rare problem. Apparently, the piston that engaged the reverse clutches was bad or incorrectly installed. This let to the reverse clutches being burned. Everything else in the trans was fine, but since the installer was technically rebuilding the trans and giving me a 3 year warranty he replaced all the clutches,etc. with his parts. We have had conference call with Bowtie yesterday. I am waiting to see today if they are willing to help out with any of the expenses.

So...with all that said thrans is back in and works great. I still need to hook up the brake switch for the converter lockup. I bought a dual pole brake switch from a HMMWV with 4L80. The switch technically works but when I adjust the brake properly the pole for cancelling convertr lockup does not activate unless the brake lever is pushed so far the brakes would be locked. I cant find any adjustment on the switch. https://www.ebay.com/itm/174542831485?chn=ps&_trkparms=ispr=1&amdata=enc:1fNBccByjRiGtwzKGjZIUlw83&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=174542831485&targetid=1644837436443&device=c&mktype=&googleloc=1013011&poi=&campaignid=16743749222&mkgroupid=138744546207&rlsatarget=pla-1644837436443&abcId=9300842&merchantid=101988484&gclid=CjwKCAjw0dKXBhBPEiwA2bmObdV8qomMFFcxkCkWT2RdpJmwwAEVOaPfEXYMshEwNuidvwjslyVCGhoC2dgQAvD_BwE

I'm getting frustrated with all that has happened and hoping to get some help without being told to use the search function. I have now decided to use a 24v relay tied to the standard brake switch to supply 12v to trans. My questions:

What wire can I splice into either under the hood or under the body to get a brake signal. Is there possibly a connection that I could simply us a "Y" packard adapter for the 24 volt signal. A "plug and play"location with an adapter I can make myself. I feel like I have the 12v side sorted.

Given that I am now going to use a relay. I thought about tying in the downshift/fan cutoff switch that is already installed on injector pump to disengage the torque converter when going wide open throttle. It seems like a good idea that yes it would work when going WOT but would also turn off fan everytime i hit the brake by backfeeding 24v. It would be great it that would work but can't figure out how to execute without negatives side effects.

As always any help appreciated.
Dan

You need to pick up the brake light signal under the dash at the switch, after that it goes through the turn signal switch and is useless for that purpose anywhere under the vehicle.
I have no idea why you would want to disable the TC lock under full throttle, on a long hill for example you could overheat the transmission as the unlocked TC makes tons of heat when loaded heavily and it should only go into lock in 4th gear, the transfer of power is more efficient in lock, the power lost in the unlocked TC is the heat I mentioned before.
If I were having a 4L built I would have asked them to put a switch on the 3rd gear servo so it would also go into lock in 3rd.
My 6L locks in all but 1st gear

 

[Glider]

You need to pick up the brake light signal under the dash at the switch, after that it goes through the turn signal switch and is useless for that purpose anywhere under the vehicle.
I have no idea why you would want to disable the TC lock under full throttle, on a long hill for example you could overheat the transmission as the unlocked TC makes tons of heat when loaded heavily and it should only go into lock in 4th gear, the transfer of power is more efficient in lock, the power lost in the unlocked TC is the heat I mentioned before.
If I were having a 4L built I would have asked them to put a switch on the 3rd gear servo so it would also go into lock in 3rd.
My 6L locks in all but 1st gear

Taking what you say into account, Why not just supply solid 12v signal. It will unlock when not in 4th. It would be the easiest and cleanest wiring option also.

 

[Mogman]

According to your schematic if you put 12V on A it will only lock in 4th, if you ground the ECM ground it will be locked all the time so don't do that.

 

[Mogman]

So if we follow along, 12V goes into A then it goes through the TC lockup solenoid, the inductor shunted by a protection diode (protects the 12V from high voltage spikes when the 12V is removed) THEN the solenoid is seeking ground to go into lockup, it goes to D where if you had an ECM (engine control module) it could decide if it wanted the TC to be locked (this is the original way the trans got into lock) then it goes to a temp switch that it is wired to keep the TC out of lock until the transmission gets warm enough, this signal then goes to B to tell the ECM, that you do not have that the transmission is warmed up, THEN it goes through a pressure switch that has been added and plumbed into the 4th gear servo circuit so IF it is in 4th gear, there is 12V on A and the transmission is warmed up the TC lockup solenoid finally gets grounded and the TC locks up. so do not connect anything to D OR B, only 12V to A and it will only lock in 4th gear.

IF for SOME reason you wanted to manually force TC lockup you could put a switch from D to ground but the TC would be in lockup ALL the time that 12V was on A and that switch was closed.

 

[MattNC]

So if we follow along, 12V goes into A then it goes through the TC lockup solenoid, the inductor shunted by a protection diode (protects the 12V from high voltage spikes when the 12V is removed) THEN the solenoid is seeking ground to go into lockup, it goes to D where if you had an ECM (engine control module) it could decide if it wanted the TC to be locked (this is the original way the trans got into lock) then it goes to a temp switch that it is wired to keep the TC out of lock until the transmission gets warm enough, this signal then goes to B to tell the ECM, that you do not have that the transmission is warmed up, THEN it goes through a pressure switch that has been added and plumbed into the 4th gear servo circuit so IF it is in 4th gear, there is 12V on A and the transmission is warmed up the TC lockup solenoid finally gets grounded and the TC locks up. so do not connect anything to D OR B, only 12V to A and it will only lock in 4th gear.
View attachment 875540
IF for SOME reason you wanted to manually force TC lockup you could put a switch from D to ground but the TC would be in lockup ALL the time that 12V was on A and that switch was closed.

I can offer that the guy in NC who did my installation has done a ton of hmmwvs and knows 700r4's inside and out (was a GM transmission mechanic for 20 yrs) and did a great job on the wiring and brake to TCC unlock setup. I've been very happy with how it functions and knock on wood I've put a few thousand miles since the bowtie 700r4 went in, including towing, etc and its not had a hickup. I could offer his name and number if you want to give him a quick call. Maybe buying a half hour of his time would sort it out if you end up getting stuck?

 

[MattNC]

I can offer that the guy in NC who did my installation has done a ton of hmmwvs and knows 700r4's inside and out (was a GM transmission mechanic for 20 yrs) and did a great job on the wiring and brake to TCC unlock setup. I've been very happy with how it functions and knock on wood I've put a few thousand miles since the bowtie 700r4 went in, including towing, etc and its not had a hickup. I could offer his name and number if you want to give him a quick call. Maybe buying a half hour of his time would sort it out if you end up getting stuck?

One other comment is we left the bowtie supplying pressure gauge in place the first 250 miles snaking it through the hole in the firewall near the parking brake. Maybe leave that in for a while to make sure your pressures are looking good?

Another thing we did was add a transmission temp gauge, I ordered it from bowtie but was a basic bosch unit. The nice thing is it fit right into the spot where the useless air filter gauge was on the dash. I've always seen my transmission between 150 and 170, even towing in 95F heat.

 

[Mullaney]

One other comment is we left the bowtie supplying pressure gauge in place the first 250 miles snaking it through the hole in the firewall near the parking brake. Maybe leave that in for a while to make sure your pressures are looking good?

Another thing we did was add a transmission temp gauge, I ordered it from bowtie but was a basic bosch unit. The nice thing is it fit right into the spot where the useless air filter gauge was on the dash. I've always seen my transmission between 150 and 170, even towing in 95F heat.

.
Good Plan @MattNC !

Having a gauge for transmission temp is definitely a good investment.
MUCH more useful for example than a stereo or a USB charging port...

 

[Mogman]

Temp gauge should not be necessary, even Matt admits it never gets close to being hot, the TH400 puts out allot more heat than the 4L60, the beauty of a lockup TC and a much more efficient design.
EDIT, now if you have a TH400 and want to scare the crap out of yourself put a temp gauge on it.

 

[Glider]

Yesterday I made a temporary harness for the converter lockup with a on/off switch. All I can say is wow. It really does calm everything down. Makes less noise, lowers rpm and really cuts down the cooling fan cycles! I haven't had on on interstate but around 50 mph it is a dream. The engine sounds much happier now.

People told me I would be happy with the swap and they were correct! Still more to do but we'll worth the effort.

 

[Glider]

Update on the swap. The trans had to come back out and be re-rebuilt. I drove the HMMWV less than 100 miles. Reverse started slipping. Felt literally like a badly slipping manual clutch. When you selected reverse it would barely make a shifting noise and barely move. I talked to Bowtie initially and they wanted us to provide line pressures and some other things for diagnosis which we did. After that they wanted me to return the trans to them for repair. Shipping would have been at least 600-700 round trip, then add the local shop charge for removal and another installation, and the time involved in shipping across country, we decided to repair ourselves and see what Bowtie could do to help on their end. Removal and inspection showed what my trans installer said to be a very rare problem. Apparently, the piston that engaged the reverse clutches was bad or incorrectly installed. This let to the reverse clutches being burned. Everything else in the trans was fine, but since the installer was technically rebuilding the trans and giving me a 3 year warranty he replaced all the clutches,etc. with his parts. We have had conference call with Bowtie yesterday. I am waiting to see today if they are willing to help out with any of the expenses.


Dan

Update on Bowtie Overdrives: I have been unsuccessful in getting any monetary help from Bowtie Overdrives. I paid a reputable shop to install the trans purchased from Bowtie. Bowtie claims we did not follow their warranty instructions by providing line pressures and other items to make sure it was shifting correctly, etc. They said they would rebuild the trans if I returned it. That's a start but shipping costs, paying the shop to R&R and the time involved with shipping/waiting on return was unacceptable and would cost nearly the same as what my local shop said they would re-rebuild and warranty the trans for 3 years. Bowtie verbally said if I had given them line pressures etc. before the failure they would have covered all expenses. That contradicts their official warranty on the website.

I "feel" like if the roles were reversed I would accommodate a customer who used a professional shop to install one of my rebuilds that failed within technically 65 miles. Not to mention inspection showed it was something very rare to both builders and neither can understand how the failure could have happened. Either way, that is how I feel, but feelings don't matter in this situation. The fact is I paid Bowtie for their product. In doing so I was told there was a warranty but did not look into the details of the warranty and the steps to make it valid. Turns out, after going to their website you have to earn their warranty. Please read the warranty attachment below. After reading this, I would not suggest anyone buy a trans from Bowtie, unless Bowtie physically installs the transmission themselves. That way there is no way they can blame a mistake on you and refuse warranty work. Plus that warranty would cover removal and reinstallation.

I have nothing against Bowtie Overdrives. If they were in my home area I would use them. My advice to anyone considering a trans swap is to purchase all necessary parts except the trans(unless it needs a rebuild) pay a local shop for rebuild/installation and get a real warranty that covers the build and installation. If you have a trans shipped in and installed by another shop you are rolling the dice.

My .02 not that anyone asked