Flat-towing / Toading
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  1. #1
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    Flat-towing / Toading

    Looking to flat tow our B5 behind an RV - e.g., four wheels on the ground with a towbar/baseplate. Looked in the manual, it says 50 mph for 50 mi. Does anyone know why this is so? We have a manual transmission, so I'm hoping someone with tranny teardown experience can comment, hopefully it's just applicable to automatics. Thanks ~

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  3. #2
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    You can tow it as far and as fast as you want, as long as it is a FWD, manual trans car.

  4. #3
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    Sharky would be the authority
    That said, I would not subject my passat 9or any car worth more than a couple thou) to this. . . .I'd buy a $1000-2000 beater (Geo Prizm)

  5. #4
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    dag! that would be a heave tow along ride! I second the beater option.
    I have witnessed damage to some automatic cars that have been towed for long distances. You could also invest into a 2 wheeled ramp and just drag the rear drag wheels. The ramp attachment would need to be pretty heavy duty since the car is not a light weight.

  6. #5
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    Tiptronic would be a problem, but the manual is fine.

  7. #6
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    Right now, we're looking to tow it to Pahrump (SMMP, track) (RUSTY!!!) in the fall, and see, if we do this in the interim, if having a toad is desirable - after all, you have an RV to pick up stakes and move along. Got a bike rack for those short trips to the camp store, or forest service trails when we're dry camping. And, after tent camping for years, this is now pseudo-camping, although I can't complain about the amenities!! Now for that satellite internet access...

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    Quote Originally Posted by PZ View Post
    Tiptronic would be a problem, but the manual is fine.
    why do you say this?

  9. #8
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    An automatic transmission is lubricated by the trans fluid being pumped thru-out the trans. Towing the car will not turn the pump and the trans will overheat and burn up the clutches.

    On a manual transmission, the gears run thru the oil and splatter it around the gear box. No pump needed.

  10. #9
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    This is verging on off topic, but I have a related question for Sharky: would flat towing be OK for a manual 4wd?

    I would guess that towing only two wheels (front or rear) on the ground would be a problem.

    It's not immediately obvious to me why towing with all four on the ground would be a disaster, though I could imagine it would turn out either way.

  11. #10
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    Quote Originally Posted by bvariant View Post
    This is verging on off topic, but I have a related question for Sharky: would flat towing be OK for a manual 4wd?

    I would guess that towing only two wheels (front or rear) on the ground would be a problem.

    It's not immediately obvious to me why towing with all four on the ground would be a disaster, though I could imagine it would turn out either way.
    Are you talking about a 4Motion Passat 1.8t manual (a rare car anyway) or are you talking about a pickup truck or SUV?

    Whichever one must be considered individually, anyway, as whether you can get away with this depends on the design of the drive system.

    In the most basic sense, if the vehicle in question has a transfer case that you can put in NEUTRAL (I'm NOT talking about the transmission here) then you could tow it on all fours. It is probably better if said car also had front hubs that are unlockable like most Fords and GM trucks, but as long as it has a transfer case that goes in neutral it doesn't matter.

    In case you don't understand, on truck type vehicles, the transfer case being put in neutral COMPLETELY disengages front and rear axles from the transmission, no matter if that transmission is manual or automatic. Next time you see a full-size 4x4 Dodge pickup driving around, look really hard at the axle of the front wheels when they turn a corner. The U-joint up there is spinning the axle because it is always "locked in" to the front wheels. That axle is also turning, but it is turning freely at the transfer case because the front drive output is effectively in "neutral" while the driver has 2wd selected. The only thing that changes on a Dodge when you select 4wd is that the transfer case starts applying power to the front driveshaft rather than letting it spin freely. I personally prefer this type because it doesn't break. Automatic hubs eventually quit working, as can be evidenced by my own personal experience and by the 4x4 aftermarket that offers manually controlled retrofit hubs (mostly for Fords) that eliminate the faulty auto hubs. Sure, the Dodge system eats more gas, but Jimmy cracked corn...I want my 4x4 to work.


    On a 1.8t manual 4motion Passat, there is no way to disconnect the driveshafts (front or rear) from the transmission. This car has a center Torsen differential that can (apparently) be ground to bits by towing with ANY wheels on the ground much less all 4. Ironically, on this car, towing on all 4 is probably EASIER than if you put the fronts on a dolly or a tow truck and tried to tow it that way.

  12. #11
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    Sharky-

    Thanks very much for the answer, which is really informative.

    Since I have a 1.8T 4Mo manual, that was the first thing I was wondering about when I posted.

    It seemed to me that towing this particular car with two wheels up (either front or rear) would be the thing most certain to fry the Torsen central differential, since there would have to be maximum front/rear slippage within the unit under those conditions.

    I was guessing that, as long as the four wheel speeds were relatively close, that the drivetrain back of the transmission would be least likely to be damaged but clearly need to learn a lot more about the rest of it.

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    Quote Originally Posted by Sharky View Post
    Are you talking about a 4Motion Passat 1.8t manual (a rare car anyway) or are you talking about a pickup truck or SUV?

    Whichever one must be considered individually, anyway, as whether you can get away with this depends on the design of the drive system.



    On a 1.8t manual 4motion Passat, there is no way to disconnect the driveshafts (front or rear) from the transmission. This car has a center Torsen differential that can (apparently) be ground to bits by towing with ANY wheels on the ground much less all 4. Ironically, on this car, towing on all 4 is probably EASIER than if you put the fronts on a dolly or a tow truck and tried to tow it that way.
    Can you explain why with the 4mo that the center diff grinds itself up? If the tranny is in neutral, doesn't the output shaft just spin freely?

  14. #13
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    As I hinted at in my last quoted paragraph, it makes sense that a manual transmission 4 mo could be towed on all 4's with the transmission in neutral. But I sure as hell wouldn't try it on MY car.

    IMHO, get a full trailer, or get a different towed car.

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    Quote Originally Posted by Sharky View Post
    As I hinted at in my last quoted paragraph, it makes sense that a manual transmission 4 mo could be towed on all 4's with the transmission in neutral. But I sure as hell wouldn't try it on MY car.

    IMHO, get a full trailer, or get a different towed car.
    the way i look at it, having the full trailer would be far more beneficial to use than the 2 wheel "toad" trailer.

    if you're towing it at an angle, your rear end is at a higher angle, thus, more succeptable to scrapes, etc.

    besides, should you kurb over a corner, it'l be the trailer curbed, not your poor car, with the sagging tail end, from the increased angle.

  16. #15
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    A friend's looking at getting a street car with the intention to track prep it. E30, A4 quattro and first gen RX-7 are on now the short list. Of course, I'm partial to the quattro... hence the questions. It gets to the track behind an RV, with flat-towing being the most 'economical' means. A light flat bed is possible, due to towing weight restrictions on the RV. It looks like we'll be looking for one almost regardless.

  17. #16
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    Interesting stuff, especially since we now own a Class A...which we didn't when this thread started...and which was the farthest thing from my mind when I bought my B5!

    ...just one more reason to kick myself for getting the Tip instead of the 5-speed standard. I guess I'm stuck with the dolly option if I decide to tow my B5.

    BTW...Sharky, congrats on hitting 10,000 post and kicking it into Overdrive!

  18. #17
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    Quote Originally Posted by PZ View Post
    An automatic transmission is lubricated by the trans fluid being pumped thru-out the trans. Towing the car will not turn the pump and the trans will overheat and burn up the clutches.

    On a manual transmission, the gears run thru the oil and splatter it around the gear box. No pump needed.
    Call me crazy, but the gears inside an automatic are still bathed in ATF fluid when the car is off, and none of the brakes or clutches are engaged, so there's no rubbing to speak of.

  19. #18
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    Quote Originally Posted by Sharky View Post


    In case you don't understand, on truck type vehicles, the transfer case being put in neutral COMPLETELY disengages front and rear axles from the transmission, no matter if that transmission is manual or automatic. Next time you see a full-size 4x4 Dodge pickup driving around, look really hard at the axle of the front wheels when they turn a corner. The U-joint up there is spinning the axle because it is always "locked in" to the front wheels.

    Dodge comment only true on 03+ trucks, the older ones the front D-shaft does not spin and the front axle is not locked, uses CAD.

  20. #19
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    Quote Originally Posted by Purplezr2 View Post
    Dodge comment only true on 03+ trucks, the older ones the front D-shaft does not spin and the front axle is not locked, uses CAD.
    That reminds me, I just remembered that Motorhome Magazine has links to PDFs of their annual "Dinghy Towing Guides" towards the bottom of their home page, FWIW.

  21. #20
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    Sharky, that was your 10,000th post. Welcome to Overdrive.

  22. #21
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    Quote Originally Posted by deusexaethera View Post
    Call me crazy, but the gears inside an automatic are still bathed in ATF fluid when the car is off, and none of the brakes or clutches are engaged, so there's no rubbing to speak of.
    ok, crazy

    you're right, the gears in automatic transmissions are always in mesh, and always in constant fluid.

    however, what pz was trying to say, is that the operation of the automatic transmissions are completely different from manuals.
    manuals have gears in mesh, and don't require a pump mechanism for cooling the oil.

    and automatic transmissions are somewhat the same, yet completely different at the same time. think of the internal operations of an automatic tranny as a pillar of planetary gearsets.

    the way it works is ALL of the gears are ALWAYS in mesh, the only difference is that there are friction clutches that are pushed into place via the pressure applied by the valvebody solenoids. now, the way this works, is by holding different parts of the gears. in neutral, everything is freewheeling, so it produces no output to the wheels, then in 1st, it applies the low/1st clutchpack and locks that part of the transmission, thereby stopping the turning of a freewheel part, and sending that power outward.

    basically, it's because of these friction surfaces, these clutch packs, that an oil cooler & active oil pump are required while the vehicle is in movement.

    these friction clutches create a lot of friction, which creates heat, which doesn't get cooled properly if the engine is off (pump is run by the rpm of the engine, and pushed through directly by the case of the torque converter and is not attached to the turbine within the tc, it's completely dependant on vehicle RPM), and thus no fluid flow, and with that, the oil gets cooked, and along with the cooking oil, you also destroy the clutches.

    if you want to destroy an automatic transmission's clutches and torque converter, towing it with it's drive wheels in contact with the road is the best way to doso.

    HOWEVER, it is possible to tow an automatic car with drivewheels on the ground. if you turn the car on, and leave it on while on your trip you will have the pump working, and can take it with you.

    be advised that the pump will not be operating to it's optimal capacity as it will just be working at idle rpm.

    you'd think that automatic transmissions are a scary mysterybox, but now that i've taken a class on them theyre Really simplistic, and awesomely designed.

  23. #22
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    I know how an auto gearbox works. I'm disputing whether or not the friction from towing a car with an automatic will really generate enough heat to break down the ATF. I don't think it will, because the wet clutches and brake bands you speak of aren't engaged when the engine is off. As far as I know, the heat that an auto gearbox makes comes strictly from the two unlocked halves of the torque converter, which won't even start spinning when the engine is off, because all of the gears are "freewheeling", as you called it, and no power can get from the wheels to the TC to make it spin.

    Or, do the parts really rub that much even when disengaged?

  24. #23
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    deus, our automatics have heat issues when driven (this is a documented issue with these ZFs). Without the cooling, you're screwed.

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    Well damn.

  26. #25
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    actually, yes, the clutches are to a point engaged...
    and they do rub enough to cause an issue if improperly used.
    that's not to say you can't push your car if you're stuck or anything, you just can't get above 10mph, i think is the limit... not sure bout that.
    picture your car up in the air. the spring isn't "pushed into position" but it still has contact on both sides.

    not as good of a picture, but it does show what i try to say.
    though it isn't engaged, the clutches are all still touching

    specially the band clutches. that thing is pretty well secured around the reverse drum 24/7 and is just loose enough to allow it to slip free into it's non-use motion.

    i'm trying to explain as best i can, but it's still a pain to explain how this actually works without a diagram in hand.

    with all this jargon said, if you have an automatic car, flatbed it. not only is it better for the car, overall, but it's the best approach to saving the tranny extra strain & possibly damage.

  27. #26
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    What if you just removed the automatic tranny during transport?

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    -engine isn't properly supported and can slip to one side and fall backwards on teh firewall.
    -cv axles will seperate as they will be loose and/or dragging.
    -torque converter can fall out
    -if the TC falls out, it can spill the fluid thus possibly providing a slipping issue.
    -damages in seperate transport
    -near imposible to remove without heavy-line tools.
    -Deffinitely imposible to remove without a vehicle lift
    -takes atleast 3 hours to remove with proper tools and knowledge
    -requires more than one person to remove.
    -heavy as fuck.
    -emphasis on last item.
    -even more emphasis on that item.
    -have fun trying to do this at home.

    i can keep going.

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