Thread: Diff problem query

Originally Posted by Ace

Thanks RM, something just doesnt feel right. What could the shudder type vibration be? I have recently fitted the pinion flange mod to remove the rubber flange, but it has only started doing it lately, sometimes you can hear a squeak or rattle coming from the drivetrain when you engage the clutch. Matt

Matt, maybe just maybe all those well paid engineers at L/R new something we didn't and thats why they fitted the rubber donut in the first place to get rid of that problem you have inherited you should throw the rubber back on and see if the shudder goes away...

Originally Posted by Ace

Hi guys, i get the impression all is not well with the rear diff. Up long hills or slopes under load there is what feels like a vibration/shudder type feeling, but if you put your foot on the clutch it stops, gearbox and case feel fine no vibration there around town you dont feel it and cruising on the highway its fine until you load it up in gear. I have just been down and jacked the rear wheels up and this is what i found.

Both rear wheels off the ground and both wheels turn but not the tailshaft.

Lock the CDL and do the same thing neither wheel will turn

Unlock CDL and jack only one wheel up and it doesnt turn, now that is wrong isnt it?

Is all this normal, i was under the impression that the tailshaft should turn, am i wrong? Matt

The last test, with one wheel off the ground and CDL unlocked is not normal, unless the handbrake is on, or the gearbox is not in neutral.

Ace,

I had a similar problem with the front driveshaft...within 1000km of it being replaced. It turned out to be a dry bearing in the Uni. It was binding.

youve changed the drive flange and fitted a uni hmm

Im going to make the following assumptions

The diff is good and all parts after are good

The handbrake is good and all parts before are good

The UJ's are servicable, the right ones, are approprieately greased and correctly installed.

The last problem is the phasing of the U/Js or damage to the slip joint. try this..


drop the propshaft and check the U/J yoke alignement with a piece of string. Both the shaft yokes should be exaxtly inline with each other or exactly 90 degrees apart. IF this is so all well and good, since the shaft is out, mark it for alignment seperate the slip joint clean inspect and grease it, reassemble and reinstall

if the yokes are out of whack, reassemble with them at alignement or 90 degrees out and remark the shaft before you put it back in.

Test drive.. if its fixed problem solved if its worse/no better drop one side of the shaft and seperate it and reassemble with the yokes 90 degrees from where they were.

I learnt this one the hard way after getting a friday arvo prop shaft from hardy spicer fitted in the front of a SWB series III rattled the front like you wouldnt believe untill it was in 4wd and under power.

15 minute fix the monday after when they realised the shaft was 45 degrees out followed by a 30 minute "huh I dont get it please explain" session where they showed me on a test bed why phasing is all important

Originally Posted by one_iota

Ace,

I had a similar problem with the front driveshaft...within 1000km of it being replaced. It turned out to be a dry bearing in the Uni. It was binding.

OI gets the prize for this one. The diff end of the shafts uni joint had seized which caused the vibration, eventually the vibration dissapeared because it flogged the uni joint out on the other end two new uni's later and she is as good as new.

Just for reference unis from a bearing supplier about $20, from land rover $33. Matt

Good result Matt.

I replaced my rear rubber coupling today. the old one didn't seem too bad after 160,000 km.... just a bit of cracking around the bolt holes and not too deep.

However the vibration I was experiencing at 100 kmh has all but gone with the new one in.

Originally Posted by Blknight.aus

...Both the shaft yokes should be exaxtly inline with each other or exactly 90 degrees apart...

I learnt this one the hard way after getting a friday arvo prop shaft from hardy spicer fitted in the front of a SWB series III rattled the front like you wouldnt believe untill it was in 4wd and under power.

15 minute fix the monday after when they realised the shaft was 45 degrees out followed by a 30 minute "huh I dont get it please explain" session where they showed me on a test bed why phasing is all important

For the rear shaft, both yokes should be inline (in phase). 90 degrees out of phase will cause vibrations.

The front shaft on coil sprung rovers should be approx 45 degrees out of phase (unless it has a double cardin joint). This is because the angle of the front diff pinion is not parallel with the t/case output shaft. The out of phase of the u-joints cancels the out of phase due to non-parallel shafts.