knocking from rear - gearbox or cv?

[Pastry]

short backstory -

~12 months ago gearbox replaced with recon unit.
~6 months ago intermittent knocking/clicking from O/S rear. lasts 1/2 hr then disappears. happens 3-4 times.
~2 months ago noise gets persistent after ~20 mins driving. jiggling o/s driveshaft stops it temporarily.

today i took the O/S driveshaft off. CV's seem ok - telescope in and out smoothly, no radial play.

does this grease look new? wondering as i was told they had been repacked when I reported the fault last service;

also there is lateral play in the axle stub at the gearbox, is this normal? not much, about 1 mil;

the sound when moving it is just like the one i've been hearing while driving.

I suspect the CVs are ok and that the gearbox has play and is starting to vibrate when hot. I'm a bit paranoid that way though. im hoping that repacking/repalcing the CVs will cure it but hoping someone can shed light on the play in the gearbox.


cheers

 

[Pastry]

took the cvs apart and there is some wear; slight dishing on the outer race where the ball bearings sit. not excessive but dont want to put them back on.

lookng around theres a wide variety of prices for CVs; £80 from ECP, £50 off ebay for searches for 944 part numbers and as low as £25 for VW parts that look identical. I heard of someone using a skoda fabia part (vw too after all).

I know theres a huge price differential on some identical parts depending on what car they're for; is there a recommended part number for the CV thats the same spec but at the cheaper end?

 

[zcacogp]

It's hard to tell from that photo whether the grease is new or not. The fact that there is grease there is a good thing.

The Alternative Parts Fitment thread lists the CV's as being common with a Ford Scorpio from '95-'98. Link here:

https://www.porscheclubgb.com/forum/tm.asp?m=467365&mpage=3

I can't help with the knocking though, sorry.


Oli.

 

[Pastry]

found some cvs for a vw transporter referenced on this page (linked from https://www.porscheclubgb.com/forum/tm.asp?m=467365);

http://www.alanara.fi/Possu/ENosat.html

for £27 (q-drive) or £31 (GKN)

http://www.eurocarparts.com/ecp/c/Volkswagen_Transporter_2.1_1988/p/car-parts/car-transmission/transmission-parts/cv-joint-kits/?657443620&1&c934a588b95a76755e0e410adfebf23b6991f0a7&000095

http://www.eurocarparts.com/ecp/c/Volkswagen_Transporter_2.1_1988/p/car-parts/car-transmission/transmission-parts/cv-joint-kits/?657443621&1&8e891718da18697cec2173bf13f57f838a313140&000095


scorpio on on fleabay for £22 posted :O

http://www.ebay.co.uk/itm/FORD-SCORPIO-REAR-CV-JOINT-100mm-NEW-95-98-/130545315790?pt=LH_DefaultDomain_3&hash=item1e651b6fce

id stick with ecp if the vw will fit as its a local shop with a counter.

 

[zcacogp]

Those look like some nice chunky savings which would be worth making. The only caveat is that, many years ago on here, there was a posting about CV joints from Golf GTi's being used on the back of a turbo by Fen (many will remember him). Apparently they fitted fine but failed within 5000 miles as they weren't made of the right material. I don't know how you check for this when buying them but, if there is an option, buy the heaviest-duty ones you can find.

Let us know which ones you buy and how you get on.


Oli.

 

[Pastry]

just found a qdrive part for the 944 on ecp even cheaper;

http://www.eurocarparts.com/search/657333041/p/home

looks like a winner. If i'd known they were that cheap i'd have just thrown the old ones in the bin and saved myself a mucky job.

 

[zcacogp]

That's VERY cheap. Are you sure it's the right part?

 

[Pastry]

ORIGINAL: zcacogp

That's VERY cheap. Are you sure it's the right part?

well, i put the car details (porsche 944 1988 2.5l petrol) in and up it popped. its part number is one up from the GKN one at £79.20 (657333041 vs 657333040). hope its not just a boot kit. [:-]

 

[WXW611]

That's a brilliant price.If the CV is worn then it is possibly transmitting pulsating movements to the hub flange producing the knock. Not been able to find acceptable figures for the end float of the hub but I would check the retaining bolt is tight, stick something in the holes to stop the flange rotating as per Haynes manual.

 

[George Elliott]

it is possibly transmitting pulsating movements to the hub flange producing the knock.

this would be my suspicion too, but the reason I think is the telescopic effect in the CV is "high resistance" due to the grease being old. The OSR always goes dry quicker than the NSR due to the proximity of the exhaust heat.

The 1mm float is OK for an older car, it was probably 0.5mm when new.

New Fing Ping CV joints for a fiver are likely made of MDF, and the ones you have are far superior if washed, cleaned, repacked with proper CV grease, and refitted.

good luck

George
944t

 

[Pastry]

Hi,

You could try the trick of swapping the two driveshafts (Left shaft to right of car and vv). This has the effect of reversing the load surfaces in the shafts (So you'd only get the problem when reversing). If it fixes it in forward motion you'd at least know the transaxle was ok, at no cost.

 

[Pastry]

Cheers for the advice.


Driveshaft was corroded (water was seeping into the boot via the corrosion, boot itsself was intact.)Picked up a 2nd hand driveshaft with one good/one slightly worn cv and bought a cheapo CV from ECP (had already ordered it by the time George chipped in). did a search on q-drive CVs and it looks like it may well be shite. time will tell. If it fails I'll put the best original one back on or buy a GKN one.

At least i'll know what im doing next time []