4 wheel drive class c
Does any company manufacture a 4WD coach?
Forum Discussion
93 Replies
- You're making me want to try to test this... I know, I can do it with my Nissan Pickup. Put manual transmission in gear. Set Parking Brake (that holds rear disc brakes) for safety. Jack one wheel and set it down on a sloping ramp made of two-by lumber, so it wants to roll backwards.
Now, put trolley jack under the axle at the other rear wheel. Lined up to roll parallel to the truck's wheels. Release parking brake but leave transmission in gear.
Safety Pilot in Driver Seat to apply Parking Brake if needed.
Use trolley jack to raise the wheel NOT on the slope.
My prediction: Truck will Roll.
Your prediction: Truck won't Move.
We'll have to see.
Wish I could try this with our Ford minivan, but it has a Limited Slip Differential. j-d wrote:
BECAUSE IT'S AN "OPEN DIFFERENTIAL" SO THE WHEEL WITH THE POOREST TRACTION WILL BE THE ONE TO SPIN. NO DIFFERENT THAN IF YOU JACKED ONE WHEEL, PUT IT IN DRIVE AND GAVE IT THE GAS. THE WHEEL YOU LIFTED WOULD SPIN.
Sorry .... but that is not right from the rear axle end of the drive train ... only from the engine end of the drive train.
Through an open differential in an unequal rear tire traction situation, the engine will indeed try to spin the easiest to spin tire ... as you say.
Jacking up one rear wheel so it has "no traction" and then having the other rear wheel turn on the ground when the vehicle tends to move off the jack ... cannot happen without the driveshaft getting torqued by the turning tire on the ground ... but the driveshaft cannot turn (much - see below) because it will be locked by the transmission mounted drum emergency brake and/or the park gear.
Now, there can possibly be enough "slop" in the overall driveshaft/emergency brake/park gear system so as to allow the jack to maybe tip over or start to tip over. I agree on this. With an emergency brake right on each wheel, this tip of the jack would not happen (unless the tire on the ground slips on the ground surface) . This is why I block both sides of the tire on the ground whenever I jack up the other side - whether it be in the front or back.
Of course in at least the last several decades Ford would not dare sell a vehicle that could roll off a jack when the other tire was on the ground - due to a person not being able to somehow lock the drive system connected to the non-jacked tire (discounting gear slop).
FWIW, the motorhome we owned before our current one came stock from GMC without a park gear in it's automatic transmission. It only had some kind of emergency brake. What a high stress design this was.pnichols wrote:
You mean that when you jack up one side of the rear of an E450 with a transmission mounted drum emergency brake engaged to change a tire that the emergency brake will NOT keep it from rolling off the the jack? THAT'S AFFIRMATIVE
If so, doesn't this also then mean that when you jack up one side of the rear of an E450 with the transmission in PARK that it can even then still roll off the jack? CORRECT
Maybe I gotta have another cup of coffee, but so far something doesn't smell right here:
1. How can it roll off the jack without the jacked axle having to turn the locked driveshaft (... locked from the drum emergency brake at the transmission and/or the park gear inside the transmission)?
BECAUSE IT'S AN "OPEN DIFFERENTIAL" SO THE WHEEL WITH THE POOREST TRACTION WILL BE THE ONE TO SPIN. NO DIFFERENT THAN IF YOU JACKED ONE WHEEL, PUT IT IN DRIVE AND GAVE IT THE GAS. THE WHEEL YOU LIFTED WOULD SPIN.
2. Where are all the lawsuits against Ford from owners of E350 and/or E450 chassis (and/or other Ford truck chassis) with transmission mounted drum emergency brakes and/or who put their transmission in park gear - but still had their vehicles roll off jacks?
CAN'T SAY, BUT THE FORD F-53 CLASS A'S WERE LIKE THAT, AND I THINK THE CHEVYS WITH "AUTO PARK" TOO (NOT CERTAIN ABOUT THE CHEVYS BUT I AM ABOUT THE FORDS). SCHOOL BUSES I USED TO WORK ON WERE LIKE THAT TOO, SO I IMAGINE IT WAS COMMON ON MANY MEDIUM DUTY TRUCKS. E-350, NO. THOSE HAVE CABLE OPERATED PARKING BRAKES IN THEIR REAR DRUMS. THAT SAID I DON'T KNOW WHAT THEY USED WHEN THEY WENT FROM REAR DRUM TO REAR DISC.j-d wrote:
If you jack one rear wheel off the ground, even with that Shaft Brake set, it can roll down off the jack because the wheel still on the ground can roll. The wheel you jacked up will turn in the opposite direction from the one rolling.
Hmmm .... :h :E :M
I guess I REALLY have to scratch my hear over that statement and also rethink how the standard differential ring gear and axle mechanism operates to make sure I'm sane.
You mean that when you jack up one side of the rear of an E450 with a transmission mounted drum emergency brake engaged to change a tire that the emergency brake will NOT keep it from rolling off the the jack?
If so, doesn't this also then mean that when you jack up one side of the rear of an E450 with the transmission in PARK that it can even then still roll off the jack?
Maybe I gotta have another cup of coffee, but so far something doesn't smell right here:
1. How can it roll off the jack without the jacked axle having to turn the locked driveshaft (... locked from the drum emergency brake at the transmission and/or the park gear inside the transmission)?
2. Where are all the lawsuits against Ford from owners of E350 and/or E450 chassis (and/or other Ford truck chassis) with transmission mounted drum emergency brakes and/or who put their transmission in park gear - but still had their vehicles roll off jacks?
(I apologize for my dumb comments here if I'm missing something obvious, in which case please clarify further.)pnichols wrote:
E-Series spec - it uses a transmission mounted drum, which sounds superior to a driveshaft based parking brake
Same effect. I called it "Driveshaft" because it keeps the Driveshaft from turning and not the Rear Brakes themselves. Yes, it's Transmission Mounted. If you jack one rear wheel off the ground, even with that Shaft Brake set, it can roll down off the jack because the wheel still on the ground can roll. The wheel you jacked up will turn in the opposite direction from the one rolling.
Setting that Brake is equivalent to putting it in Park. No better.
But Wait!!! (I feel like and infomercial...) There's More!!! That brake has its own little supply of ATF, and when the seal leaks, it's usually the one on the TRANSMISSION side, not the Driveshaft side. That means you don't see the leak, the Brake runs dry, and its internal bearings fail.j-d wrote:
But not if the vehicle's an E450 with that lousy driveshaft parking brake...
I thought my E450 had a driveshaft parking brake, too.
Now I'm not so sure ... see the parking brake line item on page 13 of this E-Series spec - it uses a transmission mounted drum, which sounds superior to a driveshaft based parking brake: https://www.fleet.ford.com/truckBBAS/non-html/2005/vs_pdf/05e-seriesvanbb.pdf- turbo...the answer probably lies in a phone call to Ujount and get a relationship started with them so that a) when you order, you have a name and b) when you have a problem...you have someone to help you thru it.
Gary Haupt - okay ,thats a top notch roof setup, mines flat aluminum with termination bar on the side that sticks up and traps water, ok now back to four wheel drive mode, ujoints leaf kit or the new coil over one. Not much info on the coil spring set up yet. Between the water damage repairs and the fwd conversion this is going to be quite a project but hopefully a worthwhile one.
harold1946 wrote:
Earth Roamer. They are built in Colorado.
Parts are built in Australia, assembled in the US. Australian home company has bit more variety than the US site
