Flat towing Humvee with 40,000 lb military tow bar

[deshet]

What are your opinions on flat towing a Humvee?
I have a 40,000 lb military tow bar.
The trip would be a thousand miles.
I would probably bring two Humvee tires with me just in case I ran into problems

I am wondering if I would need to remove the drive shafts?

I have seen the Marines locally towing Humvees using this setup

I apologize for all the questions I really just don't want tow the triple axle Farm trailer that far as storing it for a week is really a pain.

I appreciate the support

 

[Coug]

Depends on the towing vehicle.

Yes, it is definitely recommended that you disconnect the drive shafts at the differentials. Take some tape to hold the u-joint together and some straps to hold the shaft up out of the way. (I haven't seen the tape mentioned on any of the threads where people talk about disconnecting drive shafts, so not sure if the U-joints have the removable bearing caps like I'm used to or not, so just threw that in. If not, you might still find other uses for the tape)

As for how it will actually tow, it will fight you in the turns.
It is heavy, and will push you around.
If the roads are wet then don't go above 30 if there is any chance of having to brake or turn suddenly, because with zero tongue weight from a tow bar, your rear end will get pushed and shoved all over the place.

If you were only towing it a hundred miles or less and didn't have access to any trailers, then maybe do it and take back roads so you aren't going to fast and less visible. That would only be for a truck that's condition was known, and not off of some 5 minute inspection by the auction yard.

Wanting to drive it 1k miles with unknown condition of the HMMWV, especially not knowing fluid levels in the hubs or differentials, well, I highly recommend against it. It might make it all the way no issues, or it might cost you an extra week and thousands of dollars taking care of an issue that you could have taken care of in your driveway at your leisure later on.

And if you're still considering towing it with the RV, I'd highly recommend against it as the RV, unless it's that one chassis version, is not rated for it.

As for legality, unless you live in one of a couple states that allow it, any towed load over 3k lbs requires, by law, functioning brakes.
I can't stress this enough. It is illegal to tow loads over 3k lbs in almost every state in the U.S. if it does not have functioning brakes. If anything happens, you will be 100% at fault and liable, no matter who or what actually caused the incident/accident.

 

[Mogman]

Depends on the towing vehicle.

Yes, it is definitely recommended that you disconnect the drive shafts at the differentials. Take some tape to hold the u-joint together and some straps to hold the shaft up out of the way. (I haven't seen the tape mentioned on any of the threads where people talk about disconnecting drive shafts, so not sure if the U-joints have the removable bearing caps like I'm used to or not, so just threw that in. If not, you might still find other uses for the tape)

As for how it will actually tow, it will fight you in the turns.
It is heavy, and will push you around.
If the roads are wet then don't go above 30 if there is any chance of having to brake or turn suddenly, because with zero tongue weight from a tow bar, your rear end will get pushed and shoved all over the place.

If you were only towing it a hundred miles or less and didn't have access to any trailers, then maybe do it and take back roads so you aren't going to fast and less visible. That would only be for a truck that's condition was known, and not off of some 5 minute inspection by the auction yard.

Wanting to drive it 1k miles with unknown condition of the HMMWV, especially not knowing fluid levels in the hubs or differentials, well, I highly recommend against it. It might make it all the way no issues, or it might cost you an extra week and thousands of dollars taking care of an issue that you could have taken care of in your driveway at your leisure later on.

And if you're still considering towing it with the RV, I'd highly recommend against it as the RV, unless it's that one chassis version, is not rated for it.

As for legality, unless you live in one of a couple states that allow it, any towed load over 3k lbs requires, by law, functioning brakes.
I can't stress this enough. It is illegal to tow loads over 3k lbs in almost every state in the U.S. if it does not have functioning brakes. If anything happens, you will be 100% at fault and liable, no matter who or what actually caused the incident/accident.

I would add take several spare tires, you have no idea what condition or age they are.
You also must pull all the wheels and service the hubs and diffs. as they will be turning, as mentioned above not doing this can cost you allot of money and a failed trip, if one of those hubs fails and you will have no choice but to load it on a trailer, unless you have a spare, also you have no idea what condition the half shafts are in so a complete set of spares would also be a really good idea.
Take a full set of new lug nuts as I will guarantee after you pull those lug nuts that have been over tightened several times you will be glad you have them.

I will also chime in that is a really bad idea, as Coug said it will push you into big trouble if you get caught in an emergency situation and you do not have control of that with other drivers on the road, it is surprising to me how many twists and turns you are willing to go through not to do the job safely especially considering you have the equipment to do it safely

 

[TOBASH]

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Mechanically activates towed vehicle brakes.

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[98G]

I've flat towed a *bunch* of auction 6x6 5ton trucks from Ft Riley KS to Tucson AZ.

I've flat towed my 9300lb pickup truck behind 5tons, and I've flat towed CUCVs behind my pickup.

I've towed an M998 behind a jeep gladiator. These two vehicles are roughly equivalent in weight. It towed fine. Dry roads, on a nice sunny afternoon, with a copious amount of caution and experience.

For a 1000 mile trip, by all means pull the driveshafts. Don't consider doing otherwise.

I like the towbar idea substantially better than I like the little trailer idea. But you'll be at the mercy of the tires and hubs on an unknown truck.

And consider that when it was time for me to go get my M998, which was a known good running truck belonging to a fellow SS member, and even though I owned the appropriate towbar and safety equipment, I took a tandem axle gooseneck rated for 22,500 lbs and loaded it instead of flat towing it.

 

[BKubu]

My recommendation would be to have it towed. It is the safer plan. I have used a towbar to tow vehicles before, although not that far. If I had to tow something over like 20 miles, I'd get it towed or hauled. Personally, I'd rather spend the extra money for peace of mind. I wish you the best with your trip.

 

[HUMMER H1]

What you mean disconnect drive shaft? Where does this nonsense theory come from ?

There is a neutral position on the T case for a reason
I have flat towed H1 countless times, 750 miles

there is absolutely no need to remove any drive shaft.

 

[98G]

What you mean disconnect drive shaft? Where does this nonsense theory come from ?

There is a neutral position on the T case for a reason
I have flat towed H1 countless times, 750 miles

there is absolutely no need to remove any drive shaft.

View attachment 934793View attachment 934794View attachment 934795View attachment 934796View attachment 934797

The nonsense theory comes from the TM, the vessel of all knowledge relevant to the HMMWV.

 

[Coug]

The operator's manual makes it pretty clear that it is the recommended procedure for towing the HMMWV that any wheels on the ground require the prop shaft to be disconnected.

 

[HUMMER H1]

The nonsense theory comes from the TM, the vessel of all knowledge relevant to the HMMWV.

The same TM that says 250 degrees water temperature is still ok ?

Humvee is no different than millions of other 4x4 vehicles being flat towed behind RVs and other vehicles,

Transfer case in neutral, transmission in neutral
And go.

and if flat tow was so bad with drive shafts on, it wouldn’t make a difference if it was 30 miles or 300 miles.

 

[Coug]

The same TM that says 250 degrees water temperature is still ok ?

Humvee is no different than millions of other 4x4 vehicles being flat towed behind RVs and other vehicles,

Transfer case in neutral, transmission in neutral
And go.

and if flat tow was so bad with drive shafts on, it wouldn’t make a difference if it was 30 miles or 300 miles.

You obviously know better than the people that wrote the manuals on how to treat your own vehicle.

For the rest of us, no, it probably won't cause any issues, but it will affect fuel economy slightly with the extra mass being forced to spin. Short trip it likely won't be noticeable, but it does add up.

IF everything is in perfect condition then yes, it's not going to cause any damage.

On the other hand, towing a vehicle in unknown condition that may have things wrong with it, is it really worth the risk of causing damage to it? All it takes is a steady leak from the transfer case to lose all the oil and burn it up before getting home to give you a completely preventable repair bill.


edit: I couldn't find 250 being safe in the manual, but here is where it states above 230 is a no-go


edit 2: here's from the ECV/REV manual, also states 230

 

[Coug]

So now I am going to once again plug away at the legality. You can't legally flat tow it without it having operational brakes. Most states it's 3k lbs, some it's as low as 2k lbs, and some up to 5k lbs. Massachusetts allows up to 10k lbs. Missouri seems to be the only state without a requirement for towed vehicle braking.

IT IS ILLEGAL TO TOW A VEHICLE BEHIND ANOTHER IN ALMOST EVERY STATE AND MOST OF CANADA WITHOUT THE TOWED LOAD HAVING AN OPERATIONAL BRAKING SYSTEM.

Flat Towing Law - Braking Systems

Flat Towing Laws by state. Arkansas, 3000 lbs ; California, 3000 lbs ; Colorado, 3000 lbs ; Connecticut, 3000 lbs.

rvibrake.com

Unless you are taking with you some way to convert the braking system of the towed HMMWV so that it will operate when braking the tow vehicle, then what you are proposing to do is illegal and we can NOT give you any advice on how to violate the law.

 

[HUMMER H1]

Passed 300.000 miles last July , 1985 M998

I highly recommend reading TMs

 

[98G]

The same TM that says 250 degrees water temperature is still ok ?

Humvee is no different than millions of other 4x4 vehicles being flat towed behind RVs and other vehicles,

Transfer case in neutral, transmission in neutral
And go.

and if flat tow was so bad with drive shafts on, it wouldn’t make a difference if it was 30 miles or 300 miles.

Other 4x4s I've flat towed have specified t case in neutral and transmission in park. My 6spd manual Ram specifies tcase in neutral and transmission in gear.

Perhaps something turns due to parasitic drag in the M998 due to the lack of Park.

30 miles vs 300 - possibly it takes a while for something to become heat saturated.

I merely speculate. I don't know. But i strongly suspect that those who wrote the manual do know. I see no compelling reason to deviate from it.

 

[Valley Rock]

I personally recommend this method, it will save a lot of arguing, it's a lot more fun and you won't get hassled by the popo .

 

[Davetheplumber]

What you mean disconnect drive shaft? Where does this nonsense theory come from ?

There is a neutral position on the T case for a reason
I have flat towed H1 countless times, 750 miles

there is absolutely no need to remove any drive shaft.

View attachment 934793View attachment 934794View attachment 934795View attachment 934796View attachment 934797

I read in the military literature to disconnect the shafts if your going over 30mph... I have put many T-cases in N and towed chevys all over the place... Is there something different in the M1151A1 TCase? I'm with you... it just doesn't make sense but everyone is saying to disconnect. I want to pull mine on my road trips behind my pusher RV. I don't know what to think

 

[Thunderbirds]

I read in the military literature to disconnect the shafts if your going over 30mph... I have put many T-cases in N and towed chevys all over the place... Is there something different in the M1151A1 TCase? I'm with you... it just doesn't make sense but everyone is saying to disconnect. I want to pull mine on my road trips behind my pusher RV. I don't know what to think

.

Maybe it's plain CYA, but you just can't argue with the TMs. There may be some other parameters that are different in the military use compared to most civilian versions. RWH, Mogman and other old-timer engineering minds may know more.

 

[Coug]

Remember the manuals are written for the 18 year old city boy that has no idea what he is doing, and to make someone responsible in case something breaks.
You might have zero issues with towing it in neutral t-case and transmission for a million miles, or you might have a catastrophic failure from something not being exactly perfect in the shifters.
30 miles at 30 miles per hour without removing drive shafts is what the book says, and anything else is your own decision.

 

[Mogman]

First the disclaimer, I only think I know stuff, in actuality I don't know squat so if you take my advise and it all goes to hell it's not my fault
The Jeep sites say flat towing a NP242 is no problem in neutral (trans in park) basically the only difference is the Jeep NP242 has an additional shift option for 2wd that the HMMWV does not have, it is called Selec Trac
My concern would be being able to monitor the HMMWV in case a shaft or something else let loose.

 

[glcaines]

This probably has no association with flat towing a HMMWV, but I remember decades ago that I was told that you should never flat tow an automobile or truck with an automatic transmission if the transmission didn't have a rear oil pump. If you towed a vehicle without a rear oil pump, the spinning driveshaft didn't provide lubrication for the rear bearings in the transmission and the transmission would fail, regardless of whether the transmission was in neutral. I was told that if a rear oil pump wasn't present that the drive shaft had to be removed prior to towing, regardless of the distance towed. I don't know HMMWVs and don't know if they have a rear oil pump in the transmission or not.