Motorhome towing an 80 (1 Viewer)

[Tuner]

I've read all the posts regarding flat towing back to last January and still have questions...

The tow vehicle in question is a diesel pusher motorhome with a 10,000 tow capacity. In July I pulled a 4Runner to North Dakota (4700 miles) and back without any trouble...I did overfill xfer case with 75-140 synthetic and ran it in neutral with the tranny in Park. I checked at every stop and the xfer case was warm but not hot.

I'm trading for a '96 Landcruiser with awd and factory locking diffs. All this talk about a viscous coupling is making me nervious...

If I understand the previous posts, putting the xfer case in neutral disconnects the output from the transmission but the front and rear inputs are still spinning and therefore creating heat which will eventually burn up the xfer case? Is xfer case heat the primary problem or am I missing something else?

If heat is the only concern, how are xfer case fluids cooled under normal driving conditions and how could I replicate i.e. a pump or even just letting the engine idle?

BTW, givens are a 65mph cruise speed with stops every 200 miles or so.
The tow vehicle doesn't even know the cruiser is back there.

Thanks in advance for any assistance to an obviously uneducated newbie.

 

[cruiserdan]

Buy a trailer to put it on or pull BOTH driveshafts.

 

[Tuner]

I recognize good advice when I see it and thank you for it. This is by far the most competent group on the web when it comes to landcruisers. I was hoping for a little education on the subject as well. Can you help me understand what the problems are?

 

[cruiserdan]

That transfer case will not tolerate flat towing for farther than 50 miles or faster than 30 mph or it will toast the insides.

The prefered towing methods in order of preference are:

1) Flatbed truck or trailer

2) Sling from the front with the rear on dollies

3) Sling from the front with the front wheels able to spin freely

4) Flat tow, in neutral, transfer in neutral, with the above-mentioned restrictions of speed and distance.

D-

 

[woody]

pulling both driveshafts is 16 bolts...."relatively" easy....but there is still added wear-tear on the axles from being towed, and the hassle of installing/removing shafts all the time....

a good lightweight trailer will run $2000ish, and is a good investment, especially if you opt to upgrade/enhance/wheel your 80 down the road...heck, Christo trailers his 100 around

Dan, is your 3) correct, or is that "...REAR wheels able to spin freely"

 

[cruiserdan]

pulling both driveshafts is 16 bolts...."relatively" easy....but there is still added wear-tear on the axles from being towed, and the hassle of installing/removing shafts all the time....

a good lightweight trailer will run $2000ish, and is a good investment, especially if you opt to upgrade/enhance/wheel your 80 down the road...heck, Christo trailers his 100 around

Dan, is your 3) correct, or is that "...REAR wheels able to spin freely"

#3 is correct. The rear wheels are on the ground, rolling, and the fronts are dangling in the air, spinning, as opposed to being on a dolly (which it would try to drive off of :whoops: )

 

[firetruck41]

That transfer case will not tolerate flat towing for farther than 50 miles or faster than 30 mph or it will toast the insides.

Not that I don't believe you, but what is different about flat towing vs. driving it, it seems like all the same parts are moving with the same small differences between wheels/axles, around turns etc, right?

 

[cruiserdan]

Dunno fer sure, could be because the vehicle is being powerd as opposed to pulled.

Drag yours for a couple hundred miles at about 70 and then we will know fer sure...

Any way, the book says "DON'T DO IT!" so I figure there is a good reason.

 

[landtank]

I don't see any reason not to drag the beast behind you with the tranny in neutral. The oil pump within the t-case is gear driven off of the rear output shaft (I beleive) and should still cycle fluid as if you were driving it.

One thing that I WOULD DO, is to install locking hubs on the front wheels. That way with a twist of the switch you could disconnect the front wheels from the rest of the drive train for a little added safety.

 

[CruisinGA]

If I was planning on towing like this quite a bit I would install some locking hubs on the front and go to the trouble to fit a set on the rear.

I assume all that's needed for the rear is a set of custom axle shafts? Dutchman, Moser etc can take care of that pretty inexpensively.

 

[cruiserdan]

Christo has a custom lock-out setup on the rear of the shortbus.

 

[cruiserdan]

I don't see any reason not to drag the beast behind you with the tranny in neutral. The oil pump within the t-case is gear driven off of the rear output shaft (I beleive) and should still cycle fluid as if you were driving it.

One thing that I WOULD DO, is to install locking hubs on the front wheels. That way with a twist of the switch you could disconnect the front wheels from the rest of the drive train for a little added safety.

OK, you get to drag yours for 200 miles at 70 and then we'll take a peek inside the transfer...

 

[landtank]

If I had a reason to drag it 200 miles I'd do it.

 

[cruiserdan]

When you do, drag it to the southwest. That way I won't have to ship the repair parts as far........

 

[Tuner]

This is good stuff and I appreciate it! The book flatly states never to flat tow a 4Runner either. The folks who make the rear axle disconnects and the manual front hubs (Remco) told me I would fry the transmission within 100 miles. I talked with some transmission folks in California who specialize in Toyota performance and after some figuring, we arrived at the same conslusion: overfill the transfer case and check it for heat frequently. It worked very well.

Before you ask, I intend to talk with them again...as soon as I can remember who they were. In the meantime, there is some serious talent on this forum and as a longtime lurker, I hope to pick your brains!

I understand the fact that Toyota does not approve and flatly states not to do it and can appreciate their reticence at liability but I do not want a trailer and I'm looking for the actual technical reasons not to do it rather than Toyota doesn't want me to.

If heat is the only problem, it is absolutely solvable. Any further input would be fantastic.

 

[landtank]

Well, flat towing with the tranny connected is definately bad as the fluid doesn't get pump through the cooler and the tranny bakes. The only area in my mind that is a problem is the VC in the transfer case. That is why I stated locking hubs for the front so that the VC wouldn't receive any strain from the driveshafts rotating at different speeds.

If you were to do this I think it would be a first for the LC community as far as I know.

 

[Tuner]

Thanks, that VC is what is puzzling me as well. I can put a Remco pump on the tranny that would circulate the fluid and prevent any overheating. This pump would be powered by the coach's electric system.

Why would the front and rear driveshafts be rotating at different speeds and would this cause a heat problem or is there something else? Would not the electric locking diffs in the un locked position not accomplish the same thing as unlocking manual hubs ?

As a last resort, I would just crank the engine and let her idle while I tow away. The speedo will clock the miles but it is not a concern for the few extra miles/year.

Thank you for your patience, the next beer is one me!

 

[Montana Cruiser]

...heck, Christo trailers his 100 around

Why??

 

[alia176]

I'm constantly seeing diesel pushers pulling: 2002/3/4 Range Rovers (full time 4wd like ours), Trailblazers, Jeep Cherokees (with part time Tcase I'd imagine) and newer and older Grand Cherokees. Perhaps the GCs are being ordered with a part time case from new for this purpose?

I like the idea of the rear lock out hubs. What is involved with this?

 

[MTNRAT]

"Why??"

Cuz he also pulls the short bus, and or Bens toy, and all the parts everyone wants to save shipping on. You need a duramax for that. ))).
Cheers,
Sean