Flat Towing An Auto Comanche

[ron47]

No owner's manual, so no info readily available. Is there any reliable way to determine if my 1990, automatic tranny, 4.0 Comanche can be flat-towed behind an RV??

 

Thanks

[rmoore1031]

I assume behind a RV is fine. I towed my buddy's Comanche on a trailer across 3 states. Remember to put the transfer case in neutral if you have 4WD.

[cruiser54]

4wd yes. 2wd no.

[mvusse]

Do not have the engine running when you shift the transfer case into neutral, or the central axle disconnect will lock in the front axle. The 1990 transfer cases do not have a true neutral, in neutral the front drive shaft is connected to the rear.

 

Of course the safest way would be to remove both drive shafts, or put it on a trailer.

[cruiser54]

Do not have the engine running when you shift the transfer case into neutral, or the central axle disconnect will lock in the front axle. The 1990 transfer cases do not have a true neutral, in neutral the front drive shaft is connected to the rear.

 

Of course the safest way would be to remove both drive shafts, or put it on a trailer.

90 is exactly the same as 87. There is no lock between driveshaft except with the lever in one of the 4wd modes. I don't feel like typing out the whole procedure from the owner's manual, but it is not necessary to keep the engine OFF.

[coyote kid]

if you are going long distance play it safe and pull the drive shafts it doesn't take to long to pull them and put them back on anyway  

[mvusse]

 

Do not have the engine running when you shift the transfer case into neutral, or the central axle disconnect will lock in the front axle. The 1990 transfer cases do not have a true neutral, in neutral the front drive shaft is connected to the rear.

 

Of course the safest way would be to remove both drive shafts, or put it on a trailer.

90 is exactly the same as 87. There is no lock between driveshaft except with the lever in one of the 4wd modes. I don't feel like typing out the whole procedure from the owner's manual, but it is not necessary to keep the engine OFF.

 

All 231s up until ~1994 DO NOT HAVE A TRUE NEUTRAL. The procedure in the owners manual ensures the CAD stays unlocked.  Around 1994 the 231 was redesigned and gained a true neutral.

 

If you don't believe me, put your 1987 up on jackstands, shift the transfer case into neutral, spin the rear driveshaft by hand and see what the front one does. I know what my 87 does, I know what my buddy's 89 YJ does and I know what my former coworker's 90 XJ did. None of them had a true neutral.

[ron47]

Can't believe I forgot to ad the most important data point! Yes, 4WD with the "2H-4H-N-4L" manual lever. Thanks for the info. <thumbs up>

[Eagle]

 

Do not have the engine running when you shift the transfer case into neutral, or the central axle disconnect will lock in the front axle. The 1990 transfer cases do not have a true neutral, in neutral the front drive shaft is connected to the rear.

 

Of course the safest way would be to remove both drive shafts, or put it on a trailer.

90 is exactly the same as 87. There is no lock between driveshaft except with the lever in one of the 4wd modes. I don't feel like typing out the whole procedure from the owner's manual, but it is not necessary to keep the engine OFF.

 

Yes, it is necessary. The Neutral position in the early 231 transfer cases disconnects the transfer case from the input shaft (the transmission, in other words) but it leaves the front and rear driveshafts locked together. If the engine is running when you shift, the front axle disconnect will engage and you will then be trying to tow a vehicle locked in part-time 4WD -- which is not conducive to directional control.

 

We went through this same argument a year or two ago. I remember going out and jacking up my '88 to verify it.

[COMJNUT]

We went through this same argument a year or two ago. I remember going out and jacking up my '88 to verify it.

 

 

I just laughed, after I remembered I did a VERY amature video (gawd...so bad...) on my 91 for that thread what feels like years ago now.

 

 

 

just looked, December 2010...

[gogmorgo]

Of course the safest way would be to remove both drive shafts, or put it on a trailer.

 

I second putting it on a trailer. Not absolutely necessary, but it saves a whole lot of vehicle wear, takes less effort to hook up, runs less risk of dragging it around in gear without noticing and is honestly much safer. Uhaul's rates are something like $60/day to rent a trailer, and the price to buy a new car hauler is a drop in the ocean compared to an RV.

[cruiser54]

So how did the 91 through 93s with a 231 get flat towed behind RVs then? No CAD. and supposedly the change in the 231 wasn't til 94?

 

And, doesn't the CAD rely on the vacuum storage football in the front bumper? Even if the engine isn't running, there would be enough residual vacuum to engage the CAD......

[ron47]

Slightly off topic but I offer this bit of unsolicited wisdom as related to RV towing. I agree that disconnecting the drive shafts is the best way to tow and be assured that you do no damage. In my case, we tow to an RV park several hundred miles from where we began, spend a few days and do it all again. Disconnecting in my driveway is easy but I never know what kind of surface (hot asphalt, mudholes, etc) I may be dealing with on the other end. Similar issues with a trailer, although a lot of rv'ers use them, is that once you reach your destination (which is usually a fairly crowded campground) you must find a space to stow the trailer.

 

At least now I know how to get the Comanche to tow without tearing up the drive train. This forum is The Schitz when it comes to real-world knowledge and solutions. Being a noob, I appreciate not having my face slapped for asking questions that all the old timers already know the answer too. May your beverages always be cold and your tires always gain traction.

[cruiser54]

Jeep went out of their way to make sure the 4wd models could be easily towed behind RVs. It was a great selling point.

 

Having been a Service Manager and Shop Foreman at a Jeep dealer for 12 years, and then owning my own towing company for 13 years, I can assure you that Jeep's system, as designed, works perfectly. No need for doing anything more.

[airspeed]

I bought my 88 from a retired couple, they towed it behind their RV for 20 years.  My transmission, xfer case and differentials have been running fine for 306k.

[Glenn Bint]

Don’t see it defined here. My 87 is 2wd manual. Can this be flat toward?

[AZJeff]

1 hour ago, Glenn Bint said:

Don’t see it defined here. My 87 is 2wd manual. Can this be flat toward?

Any manual transmission RWD car/truck/Jeep can be flat towed.  Just be sure to put the transmission in neutral, and keep the parking brake off.

[gogmorgo]

My '91 owner's manual doesn't actually list anything about 2wd in any of the sections on towing. I've done it with my 2wd just by sticking it in neutral, although I've never gone particularly far at a time.

 

 

That said, I've heard the odd report of a vehicle in neutral somehow getting bounced into gear, leading to engine damage, although I think that's a little implausible... you'd have to smash the spinning trans output into a dead stopped input, essentially bump starting the engine with the synchros, not the clutch. Murphy's law and whatnot I guess it's a possibility, but you'd need a pretty perfect storm for it to happen. My experience working in and around campgrounds tells me it's far more likely someone just left it in gear without realizing based on that happening all the time, the internet is also flush with pics of cars severely damaged by being dragged behind big RVs in park or with the parking brake set. But user beware I guess.

If it's an option it's always going to be better to get the wheels off the road, or at least pull the driveshaft.

[Geek]

I tow my Cherokee behind the RV. I have also towed it behind the Comanche and towed the Comanche behind the Cherokee. With 2 old Jeeps sometimes one has to tow the other home.

Make sure the steering isn't locked and don't go crazy, they don't seem to mind.

[smokey]

Here is the manual for 1988

[gogmorgo]

7 hours ago, smokey said:

Here is the manual for 1988

It's good to be cautious doing this. I haven't confirmed it firsthand but I've seen reports that some transfer cases in CAD-equipped models don't have a true neutral that disconnects the driveshafts from each other in neutral. This is no concern if you still have a functioning CAD because with the engine off you'll have no vacuum to keep it engaged, but if you've permanently locked it in or swapped to a one-piece axle shaft you might find yourself going down the road with axles locked together. Probably not the end of the world if you're just rolling in a straight line with no load in the drivetrain, but it might lead to some interesting handling, and you might still see some problematic binding and at minimum crow-hopping and tire scrubbing.

Editing now because I scrolled up to where a discussion about this was happening… ten years ago. The information Cruiser presents a few posts up isn’t entirely correct. ‘91-‘93 were still CAD axles. I believe the transition happened mid-year in ‘93 but I’m not infallible in my memory either.

 

For what it's worth I bought a 3/4 ton truck at the end of last summer, drove out with the 2wd shortbed, hooked it on to the back of the new-to-me truck, and hauled it nearly 500 miles home. It went surprisingly well. Left the ax5 (manual) in neutral. The MJ followed very nicely behind the GMC. I left the steering column unlocked, and no issues with it tracking straight. Going around tighter corners you'll notice it steers itself towards the tow vehicle, it's kinda funny watching the steering wheel wind itself over as you start the turn and then wind itself back as you straighten back out again afterwards, like there was an invisible person sitting there steering the thing. Normally I would recommend a trailer for that sort of drive, but I don't have my own, would've had to screw around renting a Uhaul (it's always a screwaround when you live in the middle of nowhere without a UHaul location for over 50 miles) and fuel was not cheap at all at the time and I saved a ton of money taking the 2.5 shortbed instead of dragging a trailer 400 some miles behind my ZJ. Likely saved fuel on the return with the smaller, lighter load. Didn’t really seem to affect the big GMC too much having the little MJ drafting behind it the whole way. Other than when I touched the brakes and the badly warped rotors and worn out calliper pins made everything start banging and shaking… but that’s hardly the MJ’s fault.