开云体育

Here's a question that I'm sure doesn't get asked a lot.

I'm sure when flat-towing our MHs when they break down and need to be towed to a service center, that short distance is not an issue (when towed by a tow truck that lifts the front wheels). But for a long tow (250 miles) I'm told that the drive shaft needs to be disconnected because even though the tranny is in neutral, the engine isn't running but the rear wheels are turning some of the tranny inards so there's no lubrication going on, and this can damage the tranny. Obviously a flatbed tow truck doesn't have this issue, but I will be flat-towing my MH for a goodly distance twice a year. So what about leaving the engine running at idle while towing? Will this provide enough lubrication for the tranny even though the rear wheels are going 50 MPH? Yes, that burns about 1/2 gallon per hour, but if the drive shaft can't be disconnected, is this a viable option? Any tranny experts out there?

yes you could run the engine to keep the trans lubed. anytime the engine is running (clutch engaged) the counter shaft is slinging the lube around. in neutral the output shaft is being turned by the drive shaft and it won't move the oil as you stated
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rz

p.s.? drive shaft can be disconnected by 4 bolts and safety wired up
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rz

Thanks rz! I passed by an automatic transmission place today so I thought I'd ask them for their opinion. The ole guy there, who was aware of the transmission our motorhomes use, said if I didn't want to fart around with detaching and reattaching the drive shaft, it would be less expensive to install an outboard transmission fluid pump which would keep the ATF flowing through the tranny when I'm driving. It just needs 12v power. I like that idea! Better than burning 9 gallons of gasoline for the trip.

I've had my 3 section drive shaft out before to replace all the universal joints. But I have a feeling the rear of the shaft that attaches to the dif can't be detached unless the other sections are detached first. I could be wrong. If it's only a matter of removing those 4 nuts and sliding the rear section off the dif flange, I'll do that.

yep. forgot about the center carrier bearing. you'll have to unbolt it , disconnect from diff, then bolt it back in
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rz

I'm not entirely clear on one thing... if you idle the engine while towing, in neutral (auto trans), is that sufficient to prevent damage to the trasmission?

Seems like paying $2/hr for gas to idle the engine beats paying someone to disconnect and reconnect the driveshaft (unable to do it myself).

I plan to flat-tow my Dolphin. Here's what I was told re: this. The engine idling is fine for when the transmission is not turning the rear wheels, but when the rear wheel are turning the innards of the transmission at 55 MPH, the tranny needs a lot higher pressure than when at idle to do proper lubrication, like at the rear seal. So just idling the engine won't do it. There are two options: 1) Have an external ATF pump installed, or 2) rig up a cradle for the end of the drive shaft where it connects to the rear differential to hold it in position while you remove the 4 bolts that connect the drive shaft to the differential. Then keep the tranny in park when driving. The differential flange will turn, but the drive shaft's flange won't. And as long as there is a teeny tiny gap between the two, you'll be fine. Then when you get to where you want to be able to drive the motorhome, line up the 4 holes, install the 4 bolts and nuts, and lower the cradle a little. This is the route I'm taking. But I am handy enough to handle this. Otherwise I'd have an external ATF pump installed.