Sideways lurch, is this a 'Stag Twitch'?

[Dom]

Hi,

Ive had this problem since I first bought the car. Its best described as a sideways lurch. It occurs on a straight road, changing gears, usually between 2nd to 3rd. The revs are somewhere around 3-4k. As the clutch goes in and then releases, the car moves sideways about 1 foot, quite concerning sometimes! It gives the sensation of crabbing.

When I first came on here I read about the Stag Twitch and put it down to 'one of those things' that come with Stag ownership. However, I'm wondering now if that really is the cause. It really is a lot more than a twitch, more of a spasm!

I was thinking this through and wondered if it could be a poor bush around the gearbox or engine, causing some kind of gyroscopic effect or bushes around the diff flexing.

Has anyone else suffered this problem, or is it symptomatic of the 'Twitch'?

Thoughts would be welcome guys, as ever.

Dom

[stagmuffin]

it sure sounds like it , drive shafts sticking then releasing and do with a right old twitch . bit unnerving until you realise what's happening but easily sorted. remove the shafts and thoroughly clean the splines then lube up with cv grease and refit .you can fit a grease nipple if you drill and tap them I've got pics in my albums of this job . I would also check all of the rear bushes when down there especially the trailing arm ones and the big outer pair .
Steve

[jleyton]

My first Stag, an auto, had the twitch. My current car doesn't do it and in a funny kind of way I rather miss it

Cheers

Julian

[Dom]

Thanks Steve,
I had always assumed it was that but then started thinking, never a good thing to do.
I recently replaced the right drive shaft, left it dry though. I'll get them both lubricated when I do the bushes.
Thanks for your time,
Dom

[Dom]

Haha Julian, its certainly unique!
My wife gets it in every car she drives, every time she changes gear she moves the steering wheel, really scary!
But she's obviously a better driver than me (just in case she ever reads this).
Dom

[flying farmer]

The twitch usualy occurs during cornering if the rear bushes are good, spline lock on the rear shafts being the problem.

When the car starts jumping sideways it is often a sign the bushes are knackered. Had this problem with the Stag engined Estate despite new bushes. Turned out the problem was the stiffening brackets that go from the outer ends of the big subframe bushes to the floorpan. No matter how much I tightened them they would move on the slotted holes under full throttle acceleration in second and third gears.

I solved the problem by welding a washer in the correct place on the straps, stopped them wriggling about, but can still feel the spline lock. Don't have the same problem on the Stag but it does have new shafts.

Neil

[Richard G]

I am changing both drive shaft assemblies tomorrow, so will know if theres any difference.
First major job I have done on the car so hope it goes well.

(exchange units from Rimmers)

[Dom]

Hi Neil,

Yes, I read about the splines locking in that way, mine doesn't do this on cornering, which made me start to question the cause.

My bushes are awful, I have a box of poly to fit and I'll have a good look at the stiffening brackets also. In fact I think one is a homemade job from the PO.

Thanks for your help
Dom

[Mike Stevens]

I find that the 'twitch' comes after coming out of a corner, typically when accellerating away from a roundabout. You start to straighten up and apply power. At this moment the car is leaning out a bit (from going round the roundabout) and so the drive shafts have move in/out a bit. However, if they are a bit sticky, while power is on, they don't return to their 'proper' lengths. Then you change gear. Power is relased during this so the splines then 'unlock' and move, hence the twitch.

While typing this, it's made me think that maybe the same doesn't happen to an auto as you don't remove the power to change gear in the same way? Interesting thought.

I've had this with all the Triumph saloons I've ever had as well as the Stag. Cleaning and regreasing the shafts certainly helps but only for a while if they are worn.

Anyway, it's all part of the charm and we all get used to moving the steering wheel as we change gear!

Cheers,
Mike.

[jleyton]

While typing this, it's made me think that maybe the same doesn't happen to an auto as you don't remove the power to change gear in the same way? Interesting thought.
Cheers,
Mike.

Good explanation Mike and good theory about auto v manual.

However my first Stag was an auto and had the twitch but my current manual doesn't

Cheers

Julian

[Mike Stevens]

However my first Stag was an auto and had the twitch but my current manual doesn't

Well, it was only a theory Julian and plenty of them get shot down in flames!

Cheers,
Mike.

[Dom]

Mike,
Thanks for that, makes perfect sense. However, my lurch only happens on gear change 2nd to 3rd mostly, at higher revs. This occurs on straight roads, no corners involved.
It made me think it wasnt anything to do with sticking drive shafts but something to do with the gearbox/clutch or bushes.
First job is the bushes I think, then the straps and try from there. I was wondering if the gearbox needed new mounts?
Dom

[V Mad]

If you think the twitch is due to a knackered bush, check the play in the bushes at the front of the trailing arms. That is where any movement is most likely to cause a change of direction. But also check the integrity of the rear hub fixings to the arms as the threads can strip on the studs.

[Driveshield vehicle track]

For me new track rod and trailing arms solved it, for six months but then it came back?

[ocheye]

I looked outside this afternoon and noticed it had stopped raining. In fact it looked rather nice so I decided to take the Stag out for a spin.
I'm in the middle of giving it an 'Italian service' to try and free up sticky rings so decided to push it a bit.
I haven't had much chance to enjoy driving it since I got it, mainly motorway and poor weather conditions. Lo and behold it displayed the Stag 'lurch' or 'twitch' when it changed up (auto) after flooring it.
I wondered if I was unconsciously compensating for road camber (It lurches to the right).
I did have the o/s drive shaft changed shortly after buying it but think it may have lurched prior to that though the car was a very new experience for me at that time, particularly the auto box which feels very different to my Saab Aero auto everyday driver.
If the lurch isn't of my own making, is it something I need to become paranoid about (along with a lot of other stag issues)?
I don't think it is dangerous and I can certainly cope with it but it handles so well in many other respects (particularly dealing with the rapidly worsening road surfaces we have these days) that it seems a shame that this issue lets it down a little.
Would welcome suggested solutions
Cheers
Andy