Mechanic: "Your diff is f*cked."

Post by **Shhtuart** » Mon Mar 29, 2010 4:55 pm

Well I had a mechanic look at the car today

He told me that the CV joints are in good condition after he had a look and then he decided to take it for a test drive around the block to see what i was on about.

After turning left out of the drive it was all good, after turning left at the lights it was good, after a small right hand lane change, the car did its shuddering thing like someone shoved a stick into the front right wheel (i.e. the front right locks up and shudders until the wheels straighten out).

He believes the LSD is f*cked.

When he had it jacked up and turned the wheels there was no issue its only on the road and when the cars being turned even slightly to the right its doing it.

I've called the RACV as the comprehensive check gave the diff 100% clear and they hand balled me off to the contractors who did the work.

I'm about to tear this guy a new one...

Post by **Bennoz** » Mon Mar 29, 2010 5:50 pm

My LSD has always done that. Just dont give it so much gas when taking tight turns, thats what I do.

Post by **Shhtuart** » Mon Mar 29, 2010 5:53 pm

I wish it was that minor because i would prefer to baby it than get a replacement but its even slight lane changes that kicks it off.

Or I could just plan my drives to not include any right turns

Post by **Bennoz** » Mon Mar 29, 2010 5:56 pm

Yeah but my LSD is brand new... its just the nature of the beast.

How long has your car been doing it?

Post by **Shhtuart** » Mon Mar 29, 2010 5:59 pm

I got it last Wednesday and I noticed it on the Thursday.

It got progressively worse until it wouldn't take the slightest right turn.

Astron_Boy · Post by **Astron_Boy** » Mon Mar 29, 2010 6:23 pm

haven't had the driveshafts replaced have you?

Went threw a whole tale last week of a supposed 'fucked diff' when infact it was the shaft causing the issue...

Post by **Shhtuart** » Mon Mar 29, 2010 11:31 pm

I'm no mechanic but it may be worth having a look.

How would i test if its the driveshaft?

Astron_Boy · Post by **Astron_Boy** » Tue Mar 30, 2010 9:38 am

Shhtuart wrote:I'm no mechanic but it may be worth having a look.

How would i test if its the driveshaft?

Well, what you're describing is completely different to me.
But I will give you an insight.

The replacement shaft I had, was to short to go intto the gearbox.
The guy swapped the end CV from my old shaft onto the new CV shaft.
The problem was, there are knuckles that must line up in the shaft to make it work, mine kept slipping, causing the gearbox to buck and shudder like a bitch.

It is possible that your wheel side cv is either the wrong one and not lining up 100% when you turn a corner.
because you're loading up that wheel when you turn left, you are experiencing the shudder and most of the force is being transferred to that side of the car.

I'm not a mechanic either, and this is purely from personal experience, but perhaps it might be worth having the shaft and cvs inspected, you might have a mis matched one causing the problems...

Shane001 · Post by **Shane001** » Tue Mar 30, 2010 12:37 pm

Hey astron_boy, if you lower the front, this would change the angle of the driveshaft, could this also cause the knuckles to not line up quite right?

This might explain the wheel shudder we're experiencing since installing the Tein suspension. We're a bit worried about the effect on the driveshafts of lowering the car.

How bad is this? Will the shaft fail?

Post by **Shhtuart** » Tue Mar 30, 2010 1:03 pm

Shane, my cars been been lowered as well but I'd have no idea what make the springs were.

Could be related

Astron_Boy · Post by **Astron_Boy** » Tue Mar 30, 2010 1:29 pm

Our car is lowered only 30mm.
shafts seems to line up fine with the gearbox.

But this was more so about the size of the knuckles.
The ball joints within the shaft (not correct term) were small, and the knuckles were largers, and so they would slip over each other causing the shudder.

Shane001 · Post by **Shane001** » Tue Mar 30, 2010 2:13 pm

Yeah not the same thing then, the shafts weren't changed when we lowered it.

In my case it's probably just the LSD doing it's thing. My concern is that there is a bit of up down movement where the shaft enters the gearbox, but for now I'm just gonna have to assume that's normal. Might check it out a bit more after Bathurst.