US shift gen 4 on Hmmwv

[2mas-]

Hi, im thinking of replacing the old TCM in my Hmmwv m1045a2 with a TCM from US shift. Im having some trouble with my TCM and it is hard to troubleshoot the origininal TCM, I have tried to jump it to get fault codes but it makes no sense. So I think it is time to upgrade to a modern TCM

My question is how do I wire it to my hmmwv? Anyone done this before

What goes into the "Vehicle" port on the TCM?

"Solenoids" "PRNDL" "TSS" is OK but not sure what needs to go into the Vehicle connector. I guess it gets the 12 volt in that port to operate

Im also going to use a 24v to 12v stepdown converter, the one black dog customs sells

Thanks in advance

 

[Retiredwarhorses]

Not sure why you think it’s an “upgrade“, and IMO it’s no more difficult to TS than anything else assuming you can read, follow directions from the TM and work a DVOM.
But if you must…you need to buy the applicable harness for said upgrade from Mike over at Blackdog customs.
And no…you don’t need a stepdown connverter.

 

[FlameRed]

I posted this before so this is repeat.

I installed the aftermarket US Shift Quick 4 when I swapped out my TH400. Is is not cheap, for sure. There are others that are less expensive. US Shift tech support is great, so long as you call them - don't bother emailing, they won't respond. They now offer a report display which I love as they upgraded my older unit with out the remote display for $300.

All the Quick Shift needs is direct power from the battery and ground, connection to the TPS, and three connections on the tranny with the harness.

The good thing about the US Shift is it is pretty straight forward to change the shift points with their software and a laptop. I had to tweak mine. Also, diagnostic messages in plain English come up on the remote display - not codes. The only negative is that I cannot seem to get their digital speedometer to be accurate. It is accurate a low speeds but off at higher speeds. I have not figured out how to make it accurate in all ranges.

Regarding reliability, I only once had an issues with the Quick Shift 4. I once started the truck and the remote display would not light up and the tranny would not shift out of 2nd. I pulled off the side of the road and turned the truck off and restarted and everything was fine. Never happened again. Not sure why.

It is a pretty easy install. Get their harness plain and cover it yourself to protect it. Don't try to make up your own harness unless you are expert at that sort of thing.

But before I would start swapping systems, I could recommend buying a can of electronic cleaner, and clean the tranny connector and the grounds. It might solve your issues cheaply.

 

[frauhansen]

*snip*Im having some trouble with my TCM and it is hard to troubleshoot the origininal TCM, I have tried to jump it to get fault codes but it makes no sense.

I highly doubt that!

 

[2mas-]

Thanks for answers

My problems with the transmission started when I changed the 12v regulator on the hmmwv. A rookie mistake, I changed it since the voltage indicator was not in the green but I found out that it was the smart start box that needed to be changed then everything was ok after

I changed the regulator to a new one. But found out there was different numbers on them. Mine has numbers I have never seen in any posts before or for sale. I'll upload some pictures so you can see, maybe you have some advices?

Original on my truck N3117


The new I bought N3135


When that was installed and I fired up the truck something started smoking around the alternator couldnt find out where. After this mistake I got the fault codes DTC 8-6 and 8-7 on the TCM

 

[2mas-]

Lifting the post since I didnt get any respons on the last input here. Im looking into the changing the alternator for a non-military one and go for a 24/12v converter for the TCM. Any suggestion?

Thanks from 2mas-

 

[FlameRed]

Lifting the post since I didnt get any respons on the last input here. Im looking into the changing the alternator for a non-military one and go for a 24/12v converter for the TCM. Any suggestion?

Thanks from 2mas-

Let me see if I can be clearer. The Quick 4 does not take that much juice, so IMHO a converter is unnecessary and overly complicated. Just connect it up to the positive and negative posts of the first of your two batteries. Just make sure you put a fuse between the first 12V battery and battery ground when you connect up the Quick 4. It does not draw much current at all. So anything more is overkill IMHO. Actually, you can use a circuit beaker so it is easy to reset.

Regarding a civi alternator, when I was looking into this I found a few YouTubes on this topic, but I just went the 200 amp military generator instead.

Humvee Alternator Upgrade

BTW - You can now order the Quick-4 with a remote display. I sent mine back and exchanged it for another one with a display. They make it very easy to exchange them and it makes super easy to tweak the tune without a computer, at least for the simple stuff. I have to admit that the speed it displays on the remote display need some tweaking on mine as it reads about 4 MPH low over actual according to GPS.

 

[Coug]

Even only drawing a minimal amount of current, it still creates a voltage imbalance. Unless there is some mechanism installed to equalize the batteries, any imbalance will eventually cause a premature failure of the battery bank.

I know of no battery manufacturer that will tell you that their batteries, when installed in series, it is acceptable to place ANY additional load on one compared to the other/s.

I deal with off grid battery banks on occasion in my job, and have seen several with failures related to imbalance.

For the cost of a single automotive battery these days compared to the price of a 24-12V converter, it really isn't worth the headache to not install a converter.

If it works for you, great, more power to you, but it's highly recommended against doing so.

 

[Mogman]

Even only drawing a minimal amount of current, it still creates a voltage imbalance. Unless there is some mechanism installed to equalize the batteries, any imbalance will eventually cause a premature failure of the battery bank.

I know of no battery manufacturer that will tell you that their batteries, when installed in series, it is acceptable to place ANY additional load on one compared to the other/s.

I deal with off grid battery banks on occasion in my job, and have seen several with failures related to imbalance.

For the cost of a single automotive battery these days compared to the price of a 24-12V converter, it really isn't worth the headache to not install a converter.

If it works for you, great, more power to you, but it's highly recommended against doing so.

I agree with Coug, no imbalance is desired if only a 28V alt is installed.