Motorhome towing an 80

[Darwood]

don't know...
if you were to disconnect the front wheels and have the rear ones still connected, the VC would have to spin the front driveshaft, diff parts, axles etc. If the truck were to be slowed down suddenly, all these front parts would keep spinning and the VC would see a big rpm difference and get hot. If you have both front and rear connected to the wheels, the VC would not see much difference. Not true?

anyway, best to drop the shafts...

I think you're right. It's simular to when the front drive shaft is removed. To go anywhere the center diff needs to be locked or the VC will burn up. Where as you won't as easily burn up the VC by pulling the truck, it will see rotational differences between the front and rear shafts. I think it would be best to lock the center diff as well if locking hubs were installed for flat towing.

 

[Tuner]

I found exploded views of the 98 4runner TC and the 96 LC TC, the 4runner TC is chain driven whereas the LC TC has hard gears.

When in the neutral position, I can find no moving parts other than the gears at the end of each shaft...which are bathed in 75-90, soon to be 75-140 synthetic gear oil with as much as I can get in there to protect the bearing surfaces. Heat appears to be the only problem...unless the TC gets shifted while underway...I carry nothing in the truck...or some drive line component goes bad...In which case I'd rather is was attached to a 40,000lb bus rather than being behind the wheel.

A trailer is $2k...as is a reman TC....the next motorhome trip is not for a couple of months.

more as available.

 

[Tuner]

No need to apologize for anything you have said or done. D-

Thanks! I really don't want to bug you. The toyota book recommends the same towing methods for the 4runner...obviously a different animal. I understand Toyota's point of view, they certainly don't want to be liable for this and I wouldn't attempt it with a vehicle under warranty.

The term viscous coupler is misleading to me. I think of a VC as being like a fan clutch that becomes harder to turn as it becomes hotter. The exploded view of the TC just shows hard gears completely bathed in gear oil. When in neutral, the output gears spin and the bearings will heat up but I can't find anything else to worry about that I would not worry about while driving...

Thanks to everyone for sharing your wealth of product knowledge....the truth is out there and I intend to find it!

 

[landtank]

I think you're right. It's simular to when the front drive shaft is removed. To go anywhere the center diff needs to be locked or the VC will burn up. Where as you won't as easily burn up the VC by pulling the truck, it will see rotational differences between the front and rear shafts. I think it would be best to lock the center diff as well if locking hubs were installed for flat towing.

Nope not at all. In one instance you are trying to move a 6000 lb vehicle by locking up the VC. In the other you are trying to rotate a drive shaft. Way different load.


As far as the FSM goes, just them covering their asses. Just like the speed recommendations of using the CDL, which we all know if BS.

 

[Tuner]

As far as the FSM goes, just them covering their asses. Just like the speed recommendations of using the CDL, which we all know if BS.

If CDL is the diff lock...the book says never exceed 5mph or severe damage will occur. I wouldn't know a diff lock if it bit me in the shorts(which it may do at speed) but that seems a little onerous doesn't it?

 

[cruiserdan]

CDL is Center Diff Lock. This is what locks the viscous coupler in the transfercase. You are thinking of the axle diff locks. The axle diff locks are inhibited from locking if the vehicle speed is in excess of 5 mph and Toyota does not recommend exceeding that speed whilst locked. The reason is because of the potential to lose control of the vehicle if the tractive surface suddenly changes not because of mechanical damage because it is locked. Once locked you can drive as fast as you dare.....

 

[Tuner]

Thanks for the CDL clarification. I have another question...in looking further at an expanded view of the xfer case, I find two shift forks which in my mind means both the front and rear wheels rotation will cause nothing but a nice gear on the end of each drive shaft to spin while immersed in an oil bath.

This expanded view is straight off the Toyota tech site (courtesy of a friendly repair shop), is labeled "transfer assembly components" and carries the following model designation "1996 LAND CRUISER (RM451U)".

There is no viscous coupler visible anywhere in this schematic. The question becomes: was there and early and late model in the '96 timeframe? I cannot figure any other location for a VC.

 

[landtank]

What we are reffereing to as a VC, Toyota calls a control coupler. It's not your typical oil viscous unit. It is a self contained piece. It's located in the rear section of the t-case and is what the rear output shaft slides into.

 

[flintknapper]

Do it.

As mentioned above, locking hubs at all 4 wheels would be the easiest solution, as the '96 has a full-floater rear axle.

Agreed,

I did this 20 years ago on an early bronco that I tow a lot. The rear axle on your vehicle is already a full floater, so it should be easy. I drew up the axles I wanted and sent them to "Jeff" at Moser engineering. They sent me a fine pair of axles for just over $300.00 (1984 price). I'm dead certain they can make some for Cruisers too.

Just unlock the hubs at four corners and flat tow. Remember to lock them in again before disconnecting from the tow bar and go! The lock out hubs should all be the same so parts will be interchangable...and you can carry a spare.

Depending upon what kind of traveling you do, it can be damned inconvenient to tow a vehicle on a trailer or dolly. I worked as an engineer for Foretravel Motorhomes for 13 yrs., and can tell you that most of our customers would go to great lengths to avoid "bringing along" anything that they didn't need to.

Towing a trailer to a particular spot to go "wheeling" for the day is great, but towing one all over creation is another matter IMO.

 

[DJForrestA]

I have a 1991 do I have a gear driven T Case or a viscous coupler as well. If the TCase is lubed by the tranny turning that will be your problem. On my scout the front hubs have to be locked in and the transmissiion and tcase in neutral. The front driveshaft turns the gear that lubes transfer case when the motor isn't running.

 

[Tuner]

What we are reffereing to as a VC, Toyota calls a control coupler. It's not your typical oil viscous unit. It is a self contained piece. It's located in the rear section of the t-case and is what the rear output shaft slides into.

I see a front extension housing and a rear extension housing on the diagram. There is no control coupler on the diagram.

I also crawled under the beast and it looks just like the diagram...could the extension housing be what you are referring to?

It just occurred to me that this is a 96 LC with 180k and a clear carfax. A great toyota shop did a pre-buy inspection and found:

New tires, new brakes and rotors, an EGR flow problem, no evidence of offroad use and what appears to be a new transmission. Maybe all bets are off because I have no record of any previous mods.

They have no problems with the vehicle. After examining the diagram, they can find no reason not to flat tow. The owner is a fishing buddy so I trust what they say.

BTW, flintknapper nailed it. A trailer becomes a fantastic painintheass on an extended vacation. Probably not as much as a smoking LC left on the side of the road, but...if I screw the pooch on this one, I'll be the first to come back and say so....I love this truck!

 

[firetruck41]

FWIW, in the owners manual, flat towing is discouraged, but the main reason seems to be because it is assuming you are towing it with a strap, and the person that is driving the LC will be without power for the steering/brakes (if the vehicle is turned off, of course). Not that you won't still blow up your t-case . I am so confident that you won't harm your LC by flat towing it I will wager a 6 pack of budweiser

 

[landtank]

It's in that rear extension piece. I'll try to remember to scan the page and post it up for you later.

 

[Tuner]

It's in that rear extension piece. I'll try to remember to scan the page and post it up for you later.

Thank you! The f&r extension housings a a few inches long and are not expanded on my diagram.

I pulled the tow bracket off the 4runner and I'm welding/bolting it to the brush bar on the LC so we'll either have a definite maybe or a smokin negative before long I hope no one loses a sixpack on this...

 

[alia176]

I hope the brush bar is an ARB or similar stout design. I wouldn't feel comfortable hooking up the tow bar with the factory brush bar.

On another note, I brought this up to another mud member, Damlaker. He was looking into this and we were exchanging some emails. Here's his latest point of view:

<snip>
On that point, I have concluded that by the time you buy these items, it is cheaper to buy a trailer.

1. Blue OX Tow Bar - $500 to $700 - plus wiring installation = close to $1000

2. Internal breaking unit in the 80 to apply the brakes on the 80 when the motorhome stops = $800

3. Locking Hubs front and rear - just a guess but with hardware and install cost = $1000.

4. Things I have not thought of = $500.

Total cost $3,300.

A good used car hauler with Trailer brakes etc is about $2,000. Benefits, no wear and tear on 80, use the trailer for other things (ATVs, Snowmobiles, etc) and the ability to back up the Motorhome. (I have heard that you really cannot back up a motor home with a towed vehicle behind it as you run a big risk of snapping tie rods etc.)

<snip>

Anyway, some food for thought.

Ali

 

[flintknapper]

Nope!

I have heard that you really cannot back up a motor home with a towed vehicle behind it as you run a big risk of snapping tie rods etc.)
Ali

Done it dozens of times....no problems. The hardest thing about it is that by the time you realize you need to "correct" its almost too late. The short tow bar does not allow for any pre-warning, and corrections take a lot of space.

Doing all of this while looking in the rear monitor, at night, at Houston Hobby Airport, for 150 ft. is really fun! Try this sometime in a 40' ForeTravel. A Prevost is even more fun.

Also, on larger Class A motorhomes (Diesel Pushers), you won't even know the cruiser is back there, it'll pull it and stop it just fine.

 

[Damlaker]

Okay, sorry to keep coming back to this but I have become fixated on towing a my 80 Series Land Cruiser 4 Wheels down behind my new Motorhome. I went to a web page called RV.net - and went to their "Open Road Forum". On the following thread

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/15617024/gotomsg/15676561.cfm#15676561

it appears that at least one guy has towed his 100 Series Lexus LX470 and another guy has towed his 01 Land Cruiser 4 wheels down for 1000s of miles.

I realize it may be different than an 80 Series but it is food for thought.

Finally, in respose to Cruiser Dan's statement about what the owner manual says, in general I agree it should be followed. However, my Wife's Mini-Van , a 2002 Honda Odyssey (front wheel drive) specifically says that the front wheels must be lifted to tow the Mini-Van. Over the weekend, I saw a guy towing the same type of Mini-Van and he said he had been doing it for years. Thru RV.Net, I was able to find a link to the Honda web page and, CONTRARY TO THE OWNERS MANUAL, there is a procedure for towing the mini-van 4 wheels down. My only points is that sometimes the owners manaual takes the most conservative approach.

While I lack the technical knowledge to debate members of this board regarding whether an 80 or 100 Series can be towed 4 wheels down, it would seem that in the real world, at least a couple of folks are doing it.

Now the question is how much I am willing to gamble to "test the waters to see if it all works ON MY RIG.

Let the debate begin.

 

[Tuner]

Give me a little more time to weld up the tow bar and I'll let you know if it is expensive. Fishing and SEC football keep getting in the way.

 

[Rich]

Toyota published a TSB specifying which vehicles can be flat towed behind a motorhome. Landcruiser from 1992 - 2000 is listed as Not Towable.

Be sure to lets us know the results after you prove Toyota correct.

 

[Waggoner5]

A set of front hubs will cost you $100, a CDL switch is another $50, worst case, buy the Remco driveshaft disconnect and go on down the road. You could also purchase the part time kit for transfercase from Marks in Aus, for about the same money as above and not worry again. I have one coming for my FZJ and I will flat tow it 4 down. It will have locking hubs in fronta also.

The locking hub "kit" that Christo runs is really a set of one off axles splined to take a locking hub on the rear, so putting hubs on the rear cost more than just the cost of the hubs. He is working on getting axles made to eventually offer a kit, with hubs.