Towing an automatic (1 Viewer)

[curlyearly]

I know one can't tow an automatic four wheel drive, even with the selector in "N" but waht abiout this.

Put the gearbox selector in "P" and the car will not budge. Not put the high / lowtransfer selector in "N" and the car can be pushed.

As this centre diff box is after the gearbox / engine and as the vehicle can now be pushed with the gerabox selector in P", does this mean the gearbox / enine is indeed disconnected from the drive train and so could it succesfully and safely be towed?

 

[Lka1988]

Last time my truck needed a tow, I just put both the transmission and transfer case in "N". No sweat.

 

[maybe_a_80...]

two thoughts -

1. every full-time AWD I have ever owned had to be flat-bedded when towing was necessary. i would recommend flat bedding your 80 if it is on the road and needs to be towerd significant distance - i imagine full-time 4wd is not that different...

2. neutral for transmission and transfer case should work when the 80 needs pulled out , unstuck, etc.

 

[Ebag333]

1. every full-time AWD I have ever owned had to be flat-bedded when towing was necessary. i would recommend flat bedding your 80 if it is on the road and needs to be towerd significant distance - i imagine full-time 4wd is not that different...

I've always heard the same, but most full-time AWD's don't have a neutral on the center diff like we do. Most that I've seen are just 4 high and 4 low. What damage could you cause by towing with both the transmission and transfer case in neutral?

 

[maybe_a_80...]

I've always heard the same, but most full-time AWD's don't have a neutral on the center diff like we do. Most that I've seen are just 4 high and 4 low. What damage could you cause by towing with both the transmission and transfer case in neutral?

Agreed. But if the option is available...(to flat bed the truck)

 

[Hilux]

All Hilux PT TC's when in "N" the TC is locked. Not from the TC to the tranny, but the f and r DSs.


I'll bet an 80 will do the same(problem lyes in finding out). DON'T DO IT! Drop the shaft to put it on a dolly.


Jack it up, all 4 off the ground, TC in "N", then try to rotate one drive axle.

 

[96r50]

N on the transfer case disconnects the front and rear drive shafts from the transmission, but the two shafts are still connected together by the viscous coupler (VC). Holding one set of wheels stationary (on the hoist) while the other set is spinning 60 miles an hour (on the ground) will make the VC very unhappy.

 

[RavenTai]

N on the transfer case disconnects the front and rear drive shafts from the transmission, but the two shafts are still connected together by the viscous coupler (VC). Holding one set of wheels stationary (on the hoist) while the other set is spinning 60 miles an hour (on the ground) will make the VC very unhappy.

what 96 said,

unless you start removing drive shafts it either needs to be flat towed (all 4 wheels on road spinning same speed) or on a roll back, all 4 wheels on the tuck not turning, you cannot have one axle stationary and one turning.

BTW, the 80 is not AWD, it is full time 4 wheel drive, the difference is subtle but important in cases like this, the viscus coupler is used differently from the way it is used in AWD vehicles.

 

[IdahoDoug]

What Raven/96 said.

 

[maybe_a_80...]

BTW, the 80 is not AWD, it is full time 4 wheel drive, the difference is subtle but important in cases like this, the viscus coupler is used differently from the way it is used in AWD vehicles.

every full-time AWD I have ever owned had to be flat-bedded when towing was necessary. i would recommend flat bedding your 80 if it is on the road and needs to be towerd significant distance - i imagine full-time 4wd is not that different...

so i didn't say the 80 is AWD...

 

[Hilux]

so i didn't say the 80 is AWD...

don't worry about that being a mis quote or jab, the differences are SO minimal...


Because a manufacturer didn't put a lever in it to derail a gear into neutral or put another cog and derail for a Low range, minimal


Like I said MINIMAL , and don't worry about it.

 

[Ebag333]

N on the transfer case disconnects the front and rear drive shafts from the transmission, but the two shafts are still connected together by the viscous coupler (VC). Holding one set of wheels stationary (on the hoist) while the other set is spinning 60 miles an hour (on the ground) will make the VC very unhappy.

So for those who removed (or don't have) the VC, no problems with towing it as long as you have everything in neutral.

Yet another advantage to removing the VC?

 

[Hilux]

So for those who removed (or don't have) the VC, no problems with towing it as long as you have everything in neutral.

Yet another advantage to removing the VC?

Y'all, it cant be that simple. Yes it can be done. But if it was a std open diff the carrier would be singing a tune while on the out side everything would appear normal.


By "singing a tune" I mean rotating at (I believe) double (x2) that the speed in which its being towed.

 

[maybe_a_80...]

I just got my Factory Service Manual and thought I would post the Toyota recommended ways to tow a 80.

1. On a Flat Bed Truck:

Parking Brake Applied, transmission shift lever in "P", transfer s*** lever in "H", Center Diff Switch "off"

2. On a sling type tow truck with dollies (so all four tires are off the road):

Parking Brake Applied, transmission shift lever in "P", transfer s*** lever in "H", Center Diff Switch "off"

3. Sling type tow truck (rear wheels on the ground, front wheels free to spin):

Parking Brake released, transmission shift lever in "N", transfer shift lever in "N", Center Diff switch "off"

4. Towing with rope:

Parking Brake released, transmission shift lever in "N", transfer shift lever in "N", Center Diff switch "off".

Hint: do not tow vehicle at a speed faster than 30pmh or a distance greater than 50 miles.

 

[MikePL]

All these precautions in user manuals are to prevent dumb people from forgetting to put the t-case in N.
It is much easier to say 'NO' to towing than explain why the tranny needs to be in N and why the t-case needs to be in N. Then explain what is the viscous coupler and how to avoid killing it... You see... It is easier to write NO for the end user.

But here at ih8mud we are clever guys and we know that you can tow an 80 with 4 wheels on the ground. I recently towed it for around 20 miles with no problems (well apart from almost no brakes and no steering).

 

[sleeoffroad]

The issue is when the transfercase is in neutral is the output gears and bearings getting oil since half of the transfercase is not rotating? It is decoupled from the tranmssion so no damage there, even with the VC installed if you flat tow it with all wheels on the ground, it is the same as driving it, however the oiling is still a potential issue. I am going to be looking into this since I want to set up my 100 for flat towing behind a motorhome.

 

[RavenTai]

The issue is when the transfercase is in neutral is the output gears and bearings getting oil since half of the transfercase is not rotating? It is decoupled from the tranmssion so no damage there, even with the VC installed if you flat tow it with all wheels on the ground, it is the same as driving it, however the oiling is still a potential issue. I am going to be looking into this since I want to set up my 100 for flat towing behind a motorhome.

Cristo on the 80series HF2AV transfer the oil pump is driven by the center idler shaft. from what I can tell from the drawings it does not appear that idler shaft spins in neutral,

http://webpages.charter.net/raventai/HF2AV TRANSFER.pdf

The 100 series runs the HF2A right? is the oiling system the same?

 

[sleeoffroad]

I think so but I have to check. I wonder if overfilling it would help or an electric pump to circulate oil.

 

[sleeoffroad]

Just thought I would update this thread. I have finally taken a 100 series transfer case apart to look into the oiling and flat towing issues. 80 should be the same. There is a number of holes on the output shaft that gets oil from the oil pump. These are located where there are bearings (like an rod bearing, not tapered or roller) that ride on the shaft. So I concluded that it would not be a good idea to flat tow the truck without addressing the oiling.

Right now we have tapped the output case where the oil pump feeds the oil galleys and we will install a external 12v pump to lubricate the vehicle while towing. We will take fluid from the drain plug and then feed the transfer case via the tapped hole.

Just thought I would add this since I know I am not the only one interested in flat towing a 80 or 100 behind a motorhome.

 

[alkaline747trio]

For very short towing, isn't it truck idling, transmission in P, T-case in N?