Thread: Life of Puma Rear Diff's

Originally Posted by clubagreenie

There's always a fuse somewhere in the system. As you upgrade parts the fuse just becomes more and more expensive.

Yeah, I don't disagree with your analagy if fact its quite good.

But, with each up grade the amperage of fuse also increases.

I've probably gone tiny little 5A fuse up to a reasonable 30A.

Originally Posted by clubagreenie

There's always a fuse somewhere in the system. ...

This is commonly espoused. However the mechanical engineers on here who design these sort of components for a living don't seem to subscribe to this theory (myth). At least when we are talking about vehicle drivelines.

Originally Posted by clubagreenie

There's always a fuse somewhere in the system. As you upgrade parts the fuse just becomes more and more expensive.

Rubbish, some components are not unto the task

Originally Posted by mools

Just wondering about the drive shaft modifications both Chook and Drover are doing.

When you say re tubing to a heavier duty tube, you are referring to the tube thickness of the prop shaft right? So what is the original thickness and what thickness are you using as a replacement?

I personally have never heard of a shaft failing due to the tube failing, uj joints plenty, gearbox lay shafts also but drive shaft tubes not really. I was wondering how much of a problem this type of failure really is / how likely it is to occur. If it is a real concern should it be as much of an issue on the front shaft too, or does the differance in the length of the shafts / tubes have a significant affect on its torsional strength?

On a more general note, if up rating all components from drive members, half shafts, diff through to prop shaft then does the weak link move in to to the transfere case / gearbox? If so should something let go when out and about then would it be more likely to be a real show stopper rarther than just reducing drive by a wheel or two?

Cheers,

Ian.

The tube used for most Land Rover (I don't know about Puma's) drive shafts, is strong enough so long as you don't dent it on a rock.

A dent in the tube leads to the tube being twisted up like licorice.

Heavier wall thickness will be less likely to dent, but is not ideal for rotational inertia.

If we are talking about tube diameter, which we weren't, then the diameter that Land Rover use for 120 and 130's rear drive shafts is too small and makes it susceptible to a phenomenon called 'whirling' vibration - a good number of 130 owners put up with vibration, meanwhile Land Rover saves a couple of dollars. The tube diameter is verging on too small for a 110 rear drive shaft.

Originally Posted by Bush65

If we are talking about tube diameter, which we weren't, then the diameter that Land Rover use for 120 and 130's rear drive shafts is too small and makes it susceptible to a phenomenon called 'whirling' vibration - a good number of 130 owners put up with vibration, meanwhile Land Rover saves a couple of dollars. The tube diameter is verging on too small for a 110 rear drive shaft.

I'll see if I can get a photo of my old F100 drive shaft (it's in a neighbours paddock) and compare it to the 130 shaft, I think people will be shocked.

as far as I'm concerned the 'fuse' should not be any mechanical component, but should be loss of traction, how good would that be. if yr so worried about breaking something hone out yr drive flange drill a hole thru and drop in a shear pin

Ill file the driveline fuse away with the authentic cup holders and approved seat covers!!



Only joking
Let your feet and skill be the fuse, it's a learning curve.
Drive to the conditions or be prepared to break chit.
Simple things like driveline shock can fatigue, crack and snap stock or old stuff.
Dc

Originally Posted by goingbush

as far as I'm concerned the 'fuse' should not be any mechanical component, but should be loss of traction, how good would that be. if yr so worried about breaking something hone out yr drive flange drill a hole thru and drop in a shear pin

I think in many cases this is how it is. I'm sure I did calculations on the rover driveline and you are able to snap an axle with engine torque through the gearboxes, but the tyres would normally slip first. But you can easily generate scenarios where traction from the tyres are increased so drivelines still do break.