Tyres and drive shaft

[tricky]

eg: 245 / 45 / 17 has a 5mm smaller circ than 195 / 70 / 15 ( according to one site I checked ).

These are prob too wide for Bongo by the way. Just an eg.

That's 5.34mm on the circumference which equates to 1.7mm or 0.26% on the diameter. I'm running 245/45 * 17s. When I got the van it was shod with 235/45*17s which were a bit undersize. The 245s run fine and being he speedo back to normal. I have no problem with the tyre width fouling nor the handling issues.

[Hippotastic]

Are you still running 2WD? in which case I can't see how the front diff is going to cause the symptoms you have. Alacrity is the auto-box guru, definitely worth quizzing him on a likely gearbox fault.

Good luck.

Hi Muzz, my logic is that the front diff will still be getting driven by the front wheels, if anything is amiss after the tyre incident then there may be a chance that a damaged bearing or similar is overheating and causing friction, though I agree the more likely issue is the gearbox, and Alaric is very pro extra cooling for the gearbox oil when towing.

I am still running 2WD. I am going with Munroman. The front diff is still in play, as it is being driven by the wheels. I have not disconnected a front shaft to take it out of the equation. The symptoms seems to be 2 hours plus into a journey, which might be the diff, I doubt the gearbox. I have not looked at the diff oils, maybe I should change them as par of the course. I have checked the gearbox oil levels, which are fine, maybe the gearbox needs the sump removing and a clear out of sludge. But I have no trouble with gears at all, and it now locks out at 45ish where before it was 50 no less, and it is hanging onto the lock out down to 40 usually. Gearbox and engine seem to be running better than ever.

[dandywarhol]

I'vebBeen away for a bit and just seen this thread - read the 4 pages and think I'm seeing the picture.

Can you confirm you're running 2WD on the REAR wheels - when you say the REAR u/j collapsed, are you meaning the rear u/j on the front propshaft?

Assuming you are running rear 2WD and the front propshaft has been removed, then it sounds like the front diff is NOW giving you problems - as a result of a goosed viscous coupling!

I've been bleating on about VC problems for a few years now - here's my take on it again........

The VC is a service item, designed to act as a cheap way of doing the job of an expensive 3rd. diff (like a Range Rover etc.) The VC then will eventually wear out - its filled with a silicon substance to allow drive to take place between the rear and front propshafts. Mazda, in their wisdom, fit different sized tyres as standard and the 1% difference in rolling circumference is acceptable to them, knowing that the VC will eventually need replacing.
What shortens VC life is not changing all 4 tyres at the same time - then the rolling percentage becomes unacceptable and the silicon in the VC has to work harder and eventually becomes solid - THEN the propshafts cannot have a slight speed differential and the diffs suffer and fail.
Fitting all the same sized tyres (new) IMO will extend the life of the VC - I'm of the opinion yours is already shot!

The test of a VC (when all the propshafts are attached) is to jack up one wheel, put a long bar and socket onto the jacked up wheel's driveshaft nut and try to turn the wheel - it should turn approx. a quarter turn from memory - if not the VC is shot.

Sorry for the long winded post - the old brigade are used to it

[mikexgough]

I'vebBeen away for a bit and just seen this thread - read the 4 pages and think I'm seeing the picture.

Can you confirm you're running 2WD on the REAR wheels - when you say the REAR u/j collapsed, are you meaning the rear u/j on the front propshaft?

Assuming you are running rear 2WD and the front propshaft has been removed, then it sounds like the front diff is NOW giving you problems - as a result of a goosed viscous coupling!

I've been bleating on about VC problems for a few years now - here's my take on it again........

The VC is a service item, designed to act as a cheap way of doing the job of an expensive 3rd. diff (like a Range Rover etc.) The VC then will eventually wear out - its filled with a silicon substance to allow drive to take place between the rear and front propshafts. Mazda, in their wisdom, fit different sized tyres as standard and the 1% difference in rolling circumference is acceptable to them, knowing that the VC will eventually need replacing.
What shortens VC life is not changing all 4 tyres at the same time - then the rolling percentage becomes unacceptable and the silicon in the VC has to work harder and eventually becomes solid - THEN the propshafts cannot have a slight speed differential and the diffs suffer and fail.
Fitting all the same sized tyres (new) IMO will extend the life of the VC - I'm of the opinion yours is already shot!

The test of a VC (when all the propshafts are attached) is to jack up one wheel, put a long bar and socket onto the jacked up wheel's driveshaft nut and try to turn the wheel - it should turn approx. a quarter turn from memory - if not the VC is shot.

Sorry for the long winded post - the old brigade are used to it

Kind of what I got too from my Mazda friends in Japan.......it's a bit of a pigeon Japanese Translation but echo's what Alan posted above

Q.
Full-time 4WD for what s happening? or how it works.....

A.
The driving force is transmitted Furendi 4WD front differential rotation only when there is so viscous front and rear wheel rear-wheel drive based.
That is, when the rear wheels do not slip and dry pavement while running to the front so that the rear wheels spinning in the same rotation can not carry the force driving the front wheels has 2WD state.
The front wheels rotate faster than the rotation of the rear wheel starts to spin and the rear wheels slipped as rain or snow or dirt road, front wheel drive power is transmitted in proportion to the difference between 4WD rotation state.
That is, Furendi metaphorically speaking 4WD is not running while backing you front you rear wheel always, when running at the same rate that both your rear wheels are you front wheels are just to keep apace so it does not poke from behind, and speeds up the rear wheel once you (and start to slip) Run Run is turning faster and dig behind the front wheels for you.
You can never get ahead of the rear wheel and front wheel does not overtaken you, I dig in turn result in major power and faster speed than the front wheels on hand you your rear wheel speed.
Driving force that is stable when driving the front wheels to rear wheels when slip rear 0:100 in 2WD with front-wheel drive power is transmitted up to suit them just minutes before 50:50 2WD/4WD to automatically control.
Thus, the difference is very important because the rotation and rear tire size front and rear wheel drive 4WD (outer) must equal wear.
If you break the Bisukasu Bukkake part because of overload and constant viscous tires of different sizes.

[Muzorewa]

The VC is a service item, designed to act as a cheap way of doing the job of an expensive 3rd. diff (like a Range Rover etc.) The VC then will eventually wear out - its filled with a silicon substance to allow drive to take place between the rear and front propshafts.

Interesting, does anyone have the part numbers required, where to get, how much and how big a job to fit etc.

[waycar8]

The VC is a service item, designed to act as a cheap way of doing the job of an expensive 3rd. diff (like a Range Rover etc.) The VC then will eventually wear out - its filled with a silicon substance to allow drive to take place between the rear and front propshafts.

Interesting, does anyone have the part numbers required, where to get, how much and how big a job to fit etc.

if I remember correctly, DW said it cost £350 for a new one a while ago when he fitted a new one, could be wrong

http://www.lushprojects.com/bongopartsm ... mgno=.html

I think this is the viscous coupling again could be wrong

[dandywarhol]

Kind of what I got too from my Mazda friends in Japan.......it's a bit of a pigeon Japanese Translation but echo's what Alan posted above


If you break the Bisukasu Bukkake part because of overload and constant viscous tires of different sizes.

Haven't fitted one Wayne, info lost in translation somewhere - talking of lost in translation I thought Bukkaki was something entirely different................

[mikexgough]

Kind of what I got too from my Mazda friends in Japan.......it's a bit of a pigeon Japanese Translation but echo's what Alan posted above


If you break the Bisukasu Bukkake part because of overload and constant viscous tires of different sizes.

Haven't fitted one Wayne, info lost in translation somewhere - talking of lost in translation I thought Bukkaki was something entirely different................

yes the translation is distorted as is the way we "read" into the translation/definition....... the above means how we would say....... on inspection the wear causes leakage......

[dandywarhol]

Ah, I can see a connection............................