keep snapping drive shafts ! :(

[andy-m]

when I first got my scoob, I snapped the rear N/S drive shaft CV joint (diff end) twice in as many weeks. and i've now snapped it again, this time the splined end that goes in the diff snapped right where the recess is for the clip that holds it in the diff.
there is also a slight knock on the rear of the car, which ive been chasing for a while now and is probably the cause.

so far i've replaced the shocks, the diff, bushes on the front of the diff carrier, put a solid beatrush mount on the rear of the diff, i've looked at the lateral link bushes and they aint great, but they aint the source of the knock either.
anyone got any idea's ? cuz it's realy p1ssing me off now. i dont realy wanna be off work cuz of the car but looks like unless i get a replacement double quick, im off work !

[munk]

could the rear diff not matching up with box , ratio wise cause this?thinking that maybe drive shafts are weakest link and goin rather than destroying anything else ?? random stab in the dark??

[andy-m]

diff is deffo the right ratio. happened on my old box which was a 3.9 box and I confirmed it was a matching 3.9 diff when I fitted another one just to eliminate it as the cause of the knock.
i'm now on a P1 box from krissyb's car and it came with his diff and prop too so i know it's still all matching

[munk]

Fair play...suprised no ones managed to help you out with this mate????

[andy-m]

thanks, no ones probably been able to help me out cuz i've eliminated just about every possible cause !!!
unless anyone can come up with any sugestions, i think i'll try the whiteline KSB750 diff subframe lock kit. i don't think the subframe is the cause of the knock but i'm all out of idea's

[asperformance]

not sure on the age of your car, but if you have the later 99 type diff then the shafts are different to the earlier cars

[andy-m]

its a 94 wagon. used to have a V2 sti-ra box and diff(R160) and snapped the same driveshaft twice on that with the knock present.
not sure what year P1 the box and diff came out of but krissyB said it was an R160 diff and the shafts seem to go in fine. i've done probably 2K on it so assume driveshafts must be ok ?

[Mike L]

Watch out for the length of the shafts they are a little different each side might be the issue ?

[majorscooby]

Originally Posted by andy-m

its a 94 wagon. used to have a V2 sti-ra box and diff(R160) and snapped the same driveshaft twice on that with the knock present.
not sure what year P1 the box and diff came out of but krissyB said it was an R160 diff and the shafts seem to go in fine. i've done probably 2K on it so assume driveshafts must be ok ?

Krissy's car was a W plate i think. so a 2000.

[andy-m]

Originally Posted by Mike L

Watch out for the length of the shafts they are a little different each side might be the issue ?

nah its an open diff so ends are the same each side.
know what you mean tho as the old one was LSD and tone had to change one when he fitted the diff for me. the clip on the splines was in a different place

[Mike L]

Not the ends. the shafts are a little different in lenght!!! they could be in the wrong way round hence the problems you are having?

[andy-m]

when you say different in lenth, do you mean one is like this :-



and the other this:-

[Mike L]

NO

the shaft its self look at the diff output's not quite central one side is a little longer than the other.

If you have been changing shafts I bet the right and left shafts have been mixed up!

[Mike L]

Looking at you wanted post to I think you may have the wrong ends too or missing a clip if you have broken the inner end off I supect the shaft is not locking in the diff, they should clip in and require a sharp knock to remove them?

[andy-m]

ah no.
both shafts lock in just fine. both had clips present. I watched Jaffa put both in for me and they needed a bit of force to get them in.
the one i posted in the wanted section is an old one that i broke on the old 3.9 diff & box.
also, the 2 drive shafts I broke previously were on the old RA box I had in there and the knock on my rear end was present then too and the knock remains now that I have a completely different gearbox, prop, and diff.

[andy-m]

finaly got to the bottom of why the end of my drive shaft snapped. its the clips on the splined end that goes in to the diff.
on m,y old STI-RA drivetrain and my previous WRX, the splined end of the driveshaft has a clip on. there was also a clip in the diff. when you push the driveshaft in to the diff, one clip pops over the other and thats what prevents the driveshaft from lateral movement and holds it in place in the diff.

the groove in the drive shaft for this clip on a P1 drive shaft isnt as deep. putting a clip on the drive shaft means you cant get the shaft in to the diff. turns out a P1 diff should only have a clip in the diff and not on the drive shaft.

with shaft changed for a P1 replacement, the driveshaft appears to have gone in a little further than before!