Anumber of years ago Ford had a problem with"shudder" under acceleration in
their Fairmont models, I believe. Their fix as a special Teflon based
grease. It is pt # D2AZ-19590-A. A 1 # can cost about $13.00 . That was 15
years or so ago. I don't know if it is still available, but that situation
you describe is exactly what this grease was design to cure.
----- Original Message -----
From: "Gerald M Van Vlack" <firstname.lastname@example.org>
To: "Triumphs" <email@example.com>; "FOT" <firstname.lastname@example.org>
Sent: Thursday, July 29, 2004 5:34 PM
Subject: TR 4A IRS Twitch
> I have what I believe has been referred to as the IRS twitch in my 1966
> Basically when about half way through a corner and starting to exit I feel
> slight twitch coming from the rear of the car. It seems to correspond to
> whole car seeming to settle down on the rear suspension as though under
> I believe it's what others have described as the splines in the half
> locking up and then releasing allowing the half shafts to move with the
> suspension as they should. It's been going on for a few years but only
> noticeable when I am being aggressive in a corner and mostly right hand
> (It's a street car and not a racer). I did disassemble the half shafts
> clean and grease them 2 years ago without any real apparent improvement.
> I'm about to do it again and this time use a grease with a lot of graphite
> it on the splines.
> This leads to 2 questions:
> 1. Any grease recommendations and where do I buy the grease? NAPA Perhaps?
> What should I ask for if other than the obvious and is there actually a
> that is packed with graphite and what's it normally used for?
> 2. Has anyone done the swap from side to side on the half shafts and has
> fixed the problem? Is there an issue with the bearings now that they too
> be doing most of their rotation in the opposite direction. I doubt it but
> thought I'd ask the engineers in the group. My rear hubs are the original
> that came with the car when I bought it in 1969. No there is not even the
> slightest bit of movement in the hubs after all of these years and yes I'm
> surprised too. I have a set ready to rebuild but have never gotten to that
> job, maybe this winter.
> What's the experience of the group?
> Jerry Van Vlack