Vibration between 1k and 2k revs

[Steve-7472p]

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.

[Steve-7472p]

Thanks - I'll look into the gearbox mounts and oil. It was one of the donuts that had worn away and that's why the whole centre mounting needed replacing. I will get these looked in to.

[Steve-7472p]

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!

[Steve-7472p]

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.

[Steve-7472p]

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!

[Steve-7472p]

...that being said, yours loosened after a few years. This was immediate, so I would have to go to the local garage and kick someone's arse if they hadn't done the pretty basic job of tightening up the bolts!