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Hey Guys,

Malibu's been making a racket of late. I'm thinking perhaps the prop shaft has gone out of whack, but would appreciate any thoughts?

The symptoms are as follows:

NA6A. A road speed dependant (not gearing, or engine speed related) really loud whirring sound. Almost like bad gearbox bearings. Worst around the dreaded 60km/h. My initial thoughts were either output shaft bearing, prop shaft or diff. I thought maybe even the box or diff had a leak and had dumped all their fluids.

Upon inspection with the car raised, fluid levels in the diff and gearbox are fine. Giving the uni joints on the prop shaft a good wiggle shows no play. Twisting the prop shaft only gives a slight metallic clunk in the gear box, which I would think is normal backlash tolerances?

OK, when the prop shaft is spinning the noise is coming from about an inch or two rearwards from the front uni joint. The gearbox seems quiet, as does the diff. Looking along the prop shaft as it is spinning, I cannot see any wobble that would indicate it was out of balance. I think if it was out of balance or the joints had gone there would be a noticeable vibration?

Anyway, I hope that's enough details if someone else has experienced this, or may know what it could be. Did I mention it was REALLY loud

Jules

Wow, just got home. Thought I would have 3 or 4 replies by now.
No ideas guys, or was the question too rambling


Jules

Uni joint is hard to spot unless it is totally stuffed. Had a friend who had one go last year at 90k, so it can be luck of the draw. Couldn't see any play, but a replacement shaft fixed it.

Jules,
Jack up the rear as high as you can and place on stands.
Drop the shaft off the diff and pull out of the box.
Now rotate the uni and feel if it is smooth. I'll pretty well guarantee the unis will be notchy , and that means a new shaft or a trip to the experts to have the shaft redone with replaceable unis.
Sorry mate but VERY common on Mazdas.

Terry

Hey Terry,

Don't be sorry. A shaft would be a whole lot better than gearbox bearings!
And 10 mins to replace.

Jules

Actually looking at new replacement cost =

I'm thinking either calling MX5 Plus for a used prop shaft, or at the least getting it confirmed by a drivtrain specialist first.
Would anyone be able to recommend someone decent on the Gold Coast?

Thanks guys
Jules

tbro wrote:Jules,
Now rotate the uni and feel if it is smooth. I'll pretty well guarantee the unis will be notchy
Terry

Hey Terry, Yep. Removed the shaft and both unis are notchy in one direction and a little bit stiff the other way. They tend to click when going from centre to either side. I greased them up and took it for a drive, but no good I'm afraid. Still sounds like when Luke's X-Wing fighter was trying to hit the hole in the Death Star


Jules

Hey Jules,
Driveline Services or Hardy Spicer.
I think you'll probably pushing sh*t uphill with a straw broom trying to find a good second hand one.

I'll be taking my NA8 drive shaft to Driveline Services (as they are around the corner from my work) for a quote tomorrow and will let you know what they reckon the damage will be.

Thanks as always guys.

Jules

Driveline Services prop shaft = $550.00, EXCEPT they think it's OK.

Sent me to gearbox mob, they reckon it's the diff.
Sent me to diff mob, they think it's the diff too.


Jules

Sounds like a Serious case of DIFFerent opinions to me!