Vibration between 1k and 2k revs
Discussion
I recently had the prop shaft centre bearing replaced as a part of the unit had worn away (not the actual bearing but the ring holding it in place - apologies for not being particularly technical on the terms).
Following this I have found that I can feel vibrations through the seat when driving between rouighly 1,000 rpm and 2,000 rpm. Previously this was where I would typically have the car on cruising - around 1,100 -1,200 which was 5th gear at 30mph for example and I would accelerate up to 2k to change gears and again cruise at around 1,100. Highest being 2,000 on the dual carriageway in 6th gear.
This was not there previously and the local garage who are experienced with performance cars but not Monaros specifically have suggested that there's nothing wrong and that the new bearing with have tightened everything up. They also suggested that whilst the car could drive around at around 1k revs, it's not really designed to. 4 and 6 cylinder cars I've had in the past have very obviously not liked being at 1k unless in 1st gear, so I always cruised in them at 2k, which until now, is how the Monaro felt comfortable at around 1k (engine sound wise at least).
Sorry for the long ass spiel there - I'm just looking to find out whether the vibrations are of any concern or are really to be expected. They do not carry on higher up the rev range.
Following this I have found that I can feel vibrations through the seat when driving between rouighly 1,000 rpm and 2,000 rpm. Previously this was where I would typically have the car on cruising - around 1,100 -1,200 which was 5th gear at 30mph for example and I would accelerate up to 2k to change gears and again cruise at around 1,100. Highest being 2,000 on the dual carriageway in 6th gear.
This was not there previously and the local garage who are experienced with performance cars but not Monaros specifically have suggested that there's nothing wrong and that the new bearing with have tightened everything up. They also suggested that whilst the car could drive around at around 1k revs, it's not really designed to. 4 and 6 cylinder cars I've had in the past have very obviously not liked being at 1k unless in 1st gear, so I always cruised in them at 2k, which until now, is how the Monaro felt comfortable at around 1k (engine sound wise at least).
Sorry for the long ass spiel there - I'm just looking to find out whether the vibrations are of any concern or are really to be expected. They do not carry on higher up the rev range.
Weird one this, usually I'd 100% say not prop-shaft related as normally vibrations from this are NOT engine rev related and are only speed related - normally complaints occur between 50 and 60mph rather than a rev range.
Might be worth checking the condition of the gearbox mount. Assuming engine is running very nicely with no known issues.
I wonder if when they took the prop off, they lost some gearbox oil? Did they refill correctly? Did they use the right stuff?
That could be a worth while check because input shaft is directly related to engine revs unlike the prop which varies through the gears and it is sat in oil.
Finally what condition are the rubber donuts in at each end of the prop?
Might be worth checking the condition of the gearbox mount. Assuming engine is running very nicely with no known issues.
I wonder if when they took the prop off, they lost some gearbox oil? Did they refill correctly? Did they use the right stuff?
That could be a worth while check because input shaft is directly related to engine revs unlike the prop which varies through the gears and it is sat in oil.
Finally what condition are the rubber donuts in at each end of the prop?
I had totally forgotten I made the post on here. After driving the car more, I realised that it's not rev related but is speed related, so happens in pretty much any gear (can't really tell much in fifth as the acceleration is too slow). It happens from around 20-27mph and as people have mentioned previously about common complaints, comes back in at 50-60 mph. At 50-60 I can feel it in engine braking as well, not really in the 20s though.
Whilst this is annoying and personally, spoils driving the car, is this anything serious to worry about? I'm not really looking to keep the car much longer as I've had it over four years now, which is by far the longest I've kept any vehicle and I'm looking to go back to something a bit more raw (maybe an Evo or back to an Impreza or 200SX). I don't like the idea of moving a car on that has problems though - every car I've owned and sold, I've been confident that I'm selling a good and well maintained car onto the next owner. That and the fact that I'd like to get a decent amount for it!
Whilst this is annoying and personally, spoils driving the car, is this anything serious to worry about? I'm not really looking to keep the car much longer as I've had it over four years now, which is by far the longest I've kept any vehicle and I'm looking to go back to something a bit more raw (maybe an Evo or back to an Impreza or 200SX). I don't like the idea of moving a car on that has problems though - every car I've owned and sold, I've been confident that I'm selling a good and well maintained car onto the next owner. That and the fact that I'd like to get a decent amount for it!
As it's speed related, then you can largely discount anything from the gearbox forward.
I'd be looking at the prop still, especially as it wasn't doing it before and that's where work was last done.
A simple one, check the bolts are done up tightly from the prop shaft to the diff. I have an aftermarket 1 piece and I developed some vibrations after a few years. Similarly, these were at about 40mph and repeated at about 80mph.
Of the 3 bolts holding the propshaft to the diff yoke, 1 had fallen out, one was almost completely backed out, and one was basically finger tight...
Unsurprisingly, having them tightened up cured the vibration issues...
I'd be looking at the prop still, especially as it wasn't doing it before and that's where work was last done.
A simple one, check the bolts are done up tightly from the prop shaft to the diff. I have an aftermarket 1 piece and I developed some vibrations after a few years. Similarly, these were at about 40mph and repeated at about 80mph.
Of the 3 bolts holding the propshaft to the diff yoke, 1 had fallen out, one was almost completely backed out, and one was basically finger tight...
Unsurprisingly, having them tightened up cured the vibration issues...
Steve-7472p said:
Thanks, one thing I'm not sure of is if the garage did the mark to line up. I would assume this is standard on any car that's having this sort of work done as it would make sense that any RWD car would need the prop to go back exactly where it was before but I'm no mechanic.
Whereabouts are you based? The weather will largely ruin this I suspect, but if you wanted to swap my driveshaft on to yours for a test drive that'd be a (slightly ridiculous) option?I'm in Ipswich - honestly, I would not want to ask someone to go to that sort of effort on my behalf. Really, my main thought is whether this sort of thing has typically proven to be serious or mostly an annoyance in the past. I guess loose bolts would be pretty serious if the points where it was mounted front to rear were about to fall off!
It's worth a quick check underneath where it bolts to the diff. It's just a slide fit into the gearbox so that end will be fine.
The carrier for the centre bearing bolts to the underside so it won't hurt to check that too I suppose. If you're under there and everything seems tight, you could unbolt the rear section from the diff, rotate the rear half over (the benefits of having a centre bearing
) and bolt it back up?
I mean obviously this is something the garage should do if they've made a mess of the installation, and no idea on your access to spanners / jack / driveway etc.
The problem started after the work they did, even if you just get them to check the bolts and perhaps rotate the rear half of the propshaft in case it is simply out of balance in that respect, with access to a lift it would take 15 minutes.
The carrier for the centre bearing bolts to the underside so it won't hurt to check that too I suppose. If you're under there and everything seems tight, you could unbolt the rear section from the diff, rotate the rear half over (the benefits of having a centre bearing
) and bolt it back up?I mean obviously this is something the garage should do if they've made a mess of the installation, and no idea on your access to spanners / jack / driveway etc.
The problem started after the work they did, even if you just get them to check the bolts and perhaps rotate the rear half of the propshaft in case it is simply out of balance in that respect, with access to a lift it would take 15 minutes.
I had something similar on my 04 CV8 about eighteen months ago. A low resonance / vibration that increased as the speed increased and made you feel quite nauseous. Similar to your experience this happened after having a new centre bearing fitted. I gave it to my local garage to look at and it turned out to be a worn UJ (worn front yoke) on the propshaft. They removed the prop and sent it to a company called MPD Specialist Propshaft for repair and balance who replaced the UJ. The repair itself was £250. It’s been fine ever since touch wood.
Edited by Ronaro on Friday 2nd October 18:46
For my two penneth, I would definatly say that the mechanic as not put it in the same mounting position with the two ends, if this is not the case then it is bolt related. could be also they have damaged the bearing area of the shaft as some times these bearings take some removal.
Hope its sorted quick, keep us informed
Ade
Hope its sorted quick, keep us informed
Ade
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