Transfer Case gurus. Another flat-towing question. (2 Viewers)

[BrianSanDiego]

So, it is obviously best to drop the rear driveshaft when flat towing. But, do any of you T-case wizards know exactly which parts of the transfer case are subject to excess wear when towing in 2wd neutral?

I tow pretty often to trails less than 100 miles away, so, just wondering...

Thanks dudes!
B.

 

[BrianSanDiego]

Gonna give this one a bump homies! Don't make me take apart an old Tcase and figure out how it works

 

[DanS HJ-45]

If you have the hubs unlocked, and the rear DS removed, then the T-case should be able to spin at all, regardless of gear selection. I don't see how you would have ANY wear in that case. But then, I don't flat tow (or trailer in general).

Or are you running drive plates?

Dan

 

[71-CRUISER]

w/ the case in 2wd neutral, the only thing spinning in the case is the main output shaft which will be spinning at high speed inside the drive gears. The split cases have needle bearings inside the drive gears but the solid cases do not because they don't spin in relation to each other during normal use. It will be submerged in gear oil but I would drop the driveshaft if you plan to flat tow for any long distances.

 

[vk7ybi]

So, why does it matter which end of the TC the drive is coming from? The same gears are turning in the same oil, and being towed the load on those parts has to be less than when engine driven.. I have never seen what the problem is..

 

[e rock]

There is no such thing as 2wd neutral. When you shift into neutral, the front and rear output shafts are linked together. So if you flat tow like that, the front driveshaft will be turning also. Probably not the end of the world as long as your hubs are unlocked, but it's hardly "neutral" as you would think.


It seems I've also heard the argument that a flat-towed transfer case in neutral will not adequately distribute gear oil to the gears and bearings since not all of the gears are turning and slinging oil. I'm not totally sure on the specifics of that though.

 

[Fast Eddy]

There is no such thing as 2wd neutral. When you shift into neutral, the front and rear output shafts are linked together.

If you have a hacked shifter, or a twin-stick, you can have 2wd neutral, so only the rear output shaft would be spinning when flat towing with the drive shaft in place.

It seems I've also heard the argument that a flat-towed transfer case in neutral will not adequately distribute gear oil to the gears and bearings since not all of the gears are turning and slinging oil.

There are stories around here about this causing carnage. I take out my drive shaft for anything more than across town, and I usually just drive across town.

And now for my flat-towing rant:

Don't flat tow a '40 with anything less than a big dually or a motorhome. Even a loaded Suburban isn't heavy enough to stop a '40 in less-than-perfect conditions. If you're 100% sure it's going to be dry, and you're careful, fine, but if you have to go down a grade, or if it may rain, don't do it. I spun my wife's Suburban around towing in the rain. No fun. Big insurance bill. Don't do it.

Even in the dually we slow down to 45mph on any downhill grade and stay off the brakes.

 

[71-CRUISER]

So, why does it matter which end of the TC the drive is coming from? The same gears are turning in the same oil, and being towed the load on those parts has to be less than when engine driven.. I have never seen what the problem is..

w/ the t-case in neutral the input shaft, the idler shaft and output drive gears are not turning while the truck is moving like they would be if the case was in 2 or 4wd. The output shaft would just be spining at road speed whike the gears that ride on the shaft would be at a dead stop. You would probaby be better off flat towing w/ the t-case engaged and the trans in neutral because at that point everything would be spinning just like it would be if you were driving the truck.

And yes you can get to 2wd neutral if you remove the shifter gate for the t-case.

 

[amaurer]

If you don't have [un]locking hubs, is it still safe to flat-tow in 4wd-Neutral like this?

 

[cruiserr]

w/ the t-case in neutral the input shaft, the idler shaft and output drive gears are not turning while the truck is moving like they would be if the case was in 2 or 4wd. The output shaft would just be spining at road speed whike the gears that ride on the shaft would be at a dead stop. You would probaby be better off flat towing w/ the t-case engaged and the trans in neutral because at that point everything would be spinning just like it would be if you were driving the truck.


Think about what is going on in the trannie if you tow with it in neutral. The output shaft is spinning and everything else is not!
The output shaft is on top, the oil is in the bottom.
The correct way to flat tow is with the Transfer case in neutral!
2wd neutral would be best. And NO it is not safe to tow in 4wd
neutral if you don't have hubs to unlock. That would be just like driving it in 4wd on the pavement.

Cruiserr

 

[Poser]

Four bolts, correct?

That is what retains the rear drive shaft to the differential companion flange.

Four bolts.



Four bolts.....

 

[I Tried]

Four bolts, correct?

That is what retains the rear drive shaft to the differential companion flange.

Four bolts.



Four bolts.....

But Steve, what if you have your good cloths on????

 

[Poser]

But Steve, what if you have your good cloths on????

I do not own any bad clothes....

 

[lowenbrau]

It just amazes me that so called experts can't get their heads around this. *All* the gears turn in a t-case no matter whether in high or low, 2 or four wheel drive. The only thing that changes is which gears connect to their shafts vs spinning on them. The same is true of the transmission. If you don't want to drop the shaft and you have selectable hubs you should place the t-case in 2 hi and the transmission in N. Unmodified Cruiser t-cases engage the front shaft when in N so that option is not ideal.

 

[Cruiserdrew]

It's 4 bolts for peace of mind. Then just wire up the rear shaft to the tub. Unlock your front hubs and nothing is going to turn. Drive happy.

 

[Poser]

It just amazes me that so called experts can't get their heads around this.

Who are you accusing to be an expert?




I would not flat tow something I did not like around the block, let alone my Land Cruiser down the road....














Four bolts........

 

[Downey]

So if you are of Posers mind, get dirty and undo 4 bolts. BUT if you are a grunt head like me, just put the transfer-case in neutral and tow to your hearts content. The only gears that will be turning will be riding on submerged bearings, and with NO LOAD on them!!!

 

[BrianSanDiego]

Well thank you very much fella's. I appreciate all the information and opinions.
And yes, I did remove the shift gate so I have "true" 2wd neutral, and wouldn't be spinning up my front drive train.

So does anyone know, or care to take a guess, which assembly moves when you shift the Tcase into and out of Neutral?
Specter Off-Road Land Cruiser Parts - Page 070 Transfercase, Shafts, Gears, Gaskets & Seals

Is it possibly either the high or low output gear (21 and 24) sliding on the output shaft, and meshing and disengaging from the idler gear? And if that is the case there would be no contact between the rotating components of the output shaft and the stationary parts of the idler shaft and gears?

Or, maybe there is some sort of splined interface between the output gears and the output shaft that disengages? Like part 21 or 23? If that were the case I could see a gear being stationary and riding on the spinning shaft possibly?

I can kind of visualize it working either way, and am trying to get my two scrawny little neurons to fire in conjunction!

B.

 

[vk7ybi]

Clutch 23 is moved forward or rearward on shaft 36 by the shift fork 20 and engages with high speed gear 21 or low speed gear 24, or centralised and disengaged in the neutral position.. Drive input to the rear output shaft will turn the rear output shaft which is disengaged from the gears in neutral, the bearings the gears run on are submerged in oil, so cant run dry.. The front ouput shaft 28 is engaged to output shaft 36 with clutch 27 when 4WD is selected.. You have a modified shift gate, so this output shaft wont be turning either.. Good enough guess?

The gears dont move on the shafts, the gears are in constant contact..

 

[BrianSanDiego]

Yes, very nice guess
I now understand.

So vk7ybi, you have a great grasp on how it works, and have probably have had the individual parts in your hands... would you flat tow your 40 in neutral?

BTW, I have done a lot of searching and reading on the net about flat towing, and this thread has the most good info I have seen anywhere! Thanks!