lee Posted April 29, 2023 Report Share Posted April 29, 2023 A question for you techy guys I have a new LSD fitted. I’ve noticed on left turns (only left not right) I get this hard clunking. It sounds horrendous. On gravel the inner wheel will slip. its as iff the diff isn’t allowing any slip at all. Id like to think that the installer filled it with the right additive but I might need to drain and refill. Question is, am I doing damage to the diff driving it like this?? Does it possibly need bedding in and why isn’it doing the same on right turns ?? Quote Link to post Share on other sites
stuart Posted April 29, 2023 Report Share Posted April 29, 2023 Sounds like the wrong oil in there, we used to get that back in the Seventies racing Jaguars with LSD if the wrong oil was used. Must be genuine LSD compatible. Stuart. Quote Link to post Share on other sites
lee Posted April 29, 2023 Author Report Share Posted April 29, 2023 Yeah I was thinking I’d suck the oil out tomorrow and still some correct LSD oil in there. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted April 29, 2023 Report Share Posted April 29, 2023 (edited) When selling the stuff years ago, Castrol told us their LS gear oil was for road use and B373 was for fast road and track use. My brother ran Castrol B 373 in his GKN Powr-Lok 4.1 diff TR2 on both road and track for many years without any issues (30 k miles) . The LSD was set to give maximum grip/minimal slip by re arranging the clutch plates. He now runs a 3.7 with a Quaiffe Torsen unit which uses regular hypoid gear oil. The old 4.1 axle is stored as a spare for if or when he goes racing again. Edited April 29, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
lee Posted April 30, 2023 Author Report Share Posted April 30, 2023 I’ve determined that this is an ATB diff so effectively doesn’t need any additive but also that it should bind up as there are no plates Quote Link to post Share on other sites
stuart Posted April 30, 2023 Report Share Posted April 30, 2023 4 hours ago, lee said: I’ve determined that this is an ATB diff so effectively doesn’t need any additive but also that it should bind up as there are no plates Presumably its this one, though I notice its not recommended for IRS cars. Who fitted it? https://shop.quaife.co.uk/shop/atb-differentials/quaife-triumph-stag-tr2-tr3-tr3a-tr4a-tr5-tr6-atb-differential-qdf23k/ Stuart. Quote Link to post Share on other sites
lee Posted April 30, 2023 Author Report Share Posted April 30, 2023 Could be. It was many moons ago when I supplied it to the guy that fitted it. i don’t really understand what difference IRS would make plus it says it’s for a TR6. Quote Link to post Share on other sites
stuart Posted April 30, 2023 Report Share Posted April 30, 2023 I think I would be on the phone to Quaife on Tuesday morning asking some relevant questions then. Stuart. Quote Link to post Share on other sites
lee Posted April 30, 2023 Author Report Share Posted April 30, 2023 Yeah I would do only I think this one is a copy. Even so I’m not sure what makes it clunk Quote Link to post Share on other sites
stuart Posted April 30, 2023 Report Share Posted April 30, 2023 1 hour ago, lee said: Yeah I would do only I think this one is a copy. Even so I’m not sure what makes it clunk You could just ring them anyway, worst they can do is tell you to go away, they might have some idea of the problem. Stuart. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted April 30, 2023 Report Share Posted April 30, 2023 (edited) Difference between rigid axle TR and IRS LSD or regular diff is the provision of a thrust button in the centre of the diff unit for the rigid axle half shafts to thrust against. IRS axles have no such requirement so the diff unit does not have the thrust button fitted. PS this is for Girling braked cars only as the Lockheed axle uses a different spline on the half shaft that fits in the diff. Edited April 30, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
stuart Posted April 30, 2023 Report Share Posted April 30, 2023 11 minutes ago, BlueTR3A-5EKT said: Difference between rigid axle TR and IRS LSD or regular diff is the provision of a thrust button in the centre of the diff unit for the rigid axle half shafts to thrust against. IRS axles have no such requirement so the diff unit does not have the thrust button fitted. PS this is for Girling braked cars only as the Lockheed axle uses a different spline on the half shaft that fits in the diff. So if there is a thrust button in it would that cause the problem? Stuart. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted April 30, 2023 Report Share Posted April 30, 2023 (edited) Unless of course the side shafts have been jammed into the IRS diff from either side and are causing the diff assy to not rotate freely. Simple check would be pull one side shaft out the diff and poke inside with a length of rod. The depth would need to be greater than the side shaft length. The thrust button is about an inch long. If no thrust button is fitted, the depth would exceed the side shaft length. That is what you want to find. Edited April 30, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
lee Posted April 30, 2023 Author Report Share Posted April 30, 2023 3 hours ago, stuart said: You could just ring them anyway, worst they can do is tell you to go away, they might have some idea of the problem. Stuart. Indeed yes, act ignorant (which comes naturally to me ) Quote Link to post Share on other sites
lee Posted April 30, 2023 Author Report Share Posted April 30, 2023 2 hours ago, BlueTR3A-5EKT said: Unless of course the side shafts have been jammed into the IRS diff from either side and are causing the diff assy to not rotate freely. Simple check would be pull one side shaft out the diff and poke inside with a length of rod. The depth would need to be greater than the side shaft length. The thrust button is about an inch long. If no thrust button is fitted, the depth would exceed the side shaft length. That is what you want to find. Ok thanks for the detailed explanation. very techy. So I did a sharp right hand U turn and it was perfect. Left hand turns cause the clunking and the binding up of that inner wheel. Is this consistent with what you describe?? Quote Link to post Share on other sites
roy53 Posted April 30, 2023 Report Share Posted April 30, 2023 Lee i use a company in Otford just around the corner from the Quaife factory. They have fitted torque bias and lsd quaife diffs for me so pop over to them and get it checked as expensive if damaged. Road race [ if you cannot them i will search for details ] Roy Quote Link to post Share on other sites
lee Posted May 1, 2023 Author Report Share Posted May 1, 2023 9 hours ago, roy53 said: Lee i use a company in Otford just around the corner from the Quaife factory. They have fitted torque bias and lsd quaife diffs for me so pop over to them and get it checked as expensive if damaged. Road race [ if you cannot them i will search for details ] Roy Thanks Roy. Yes a father and son set up. They’re very knowledgeable. Built my 3J diff for my RS. Good call Quote Link to post Share on other sites
Hamish Posted May 1, 2023 Report Share Posted May 1, 2023 Do these planet gear types still have the Ramps like the plate ones as these can have a heavy click on tight slow turns that can be adjusted. they also don’t, as I understand it, drive if one wheel off the ground unlike the plate versions. could these be reasons for the symptoms. glad you have a specialist known to you. I was going to recommend Pete Cox and sons. They fitted my plate 3J engineering version. https://petecoxsportscars.co.uk Quote Link to post Share on other sites
Mike C Posted May 1, 2023 Report Share Posted May 1, 2023 "they also don’t, as I understand it, drive if one wheel off the ground unlike the plate versions. "- Isn't the prime purpose of a LSD to drive both wheels forward regardless of each wheel's grip? Quote Link to post Share on other sites
lee Posted May 1, 2023 Author Report Share Posted May 1, 2023 1 hour ago, Hamish said: Do these planet gear types still have the Ramps like the plate ones as these can have a heavy click on tight slow turns that can be adjusted. they also don’t, as I understand it, drive if one wheel off the ground unlike the plate versions. could these be reasons for the symptoms. glad you have a specialist known to you. I was going to recommend Pete Cox and sons. They fitted my plate 3J engineering version. https://petecoxsportscars.co.uk Hi Peter im not sure. I’ve experienced clicking on a late Aston were it had sat for too long causing the plates to dry out a bit. This is a heavy clonk and continues with rotation. Except on a loose surface where it allows the wheel to slip. Quote Link to post Share on other sites
lee Posted May 1, 2023 Author Report Share Posted May 1, 2023 36 minutes ago, Mike C said: "they also don’t, as I understand it, drive if one wheel off the ground unlike the plate versions. "- Isn't the prime purpose of a LSD to drive both wheels forward regardless of each wheel's grip? I jacked it up on the diff yesterday. I turned one wheel and the other went in the same direction. I also couldn’t turn one wheel if the opposite one was held still. I didn’t think this was normal for an ATB Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 1, 2023 Report Share Posted May 1, 2023 Notes from Quaiffe https://www.quaife.co.uk/customer-service/technical-support/ Quote Link to post Share on other sites
Mike C Posted May 1, 2023 Report Share Posted May 1, 2023 "I turned one wheel and the other went in the same direction"- that's the test I use to check if a car really has an LSD fitted (some people have been known to tell porkies about such things). If both wheels turn in the same direction there's an LSD fitted. Quote Link to post Share on other sites
roy53 Posted May 1, 2023 Report Share Posted May 1, 2023 4 hours ago, lee said: I jacked it up on the diff yesterday. I turned one wheel and the other went in the same direction. I also couldn’t turn one wheel if the opposite one was held still. I didn’t think this was normal for an ATB No it's not. One wheel up on an LSD and it shouldn't turn. So lift a wheel and the other still drives. ditto on an ATB and it will / should turn. This is why when on a slippery , damp or lifting a wheel they go back to standard diff so no drive on the one touching the road. Why i changed both competition cars to LSD Roy Quote Link to post Share on other sites
lee Posted May 1, 2023 Author Report Share Posted May 1, 2023 Yes it’s hard to turn the lifted wheel but it does turn. I performed this task just to see if it would clonk but it didn’t. I suppose it only does it when it has power through the prop. Probably if I coast round a Left hander I suspect it won’t clonk Quote Link to post Share on other sites
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