Quick gearbox replacement ??
Discussion
My gearbox has had a barely noticeable 'knock' for a little while now. As long as it didn't get any worse, I wasn't going to do anything about it until after SCH.
Last week it took a bit of turn for the worse and this morning was no better. No choice, 'box out and either rebuilt or replaced before SCH. I can't run the risk of it failing completely during a spirited run to Silverstone. B***ox.
I haven't a clue what has gone - the noise is a heavy 'clunk' which is slightly worse when the car is coasting in neutral and the transmission is not under load. It's rotational and there is one 'clunk' per turn of the prop shaft. Because of this, its more noticeable at low speed.
Its definitely coming from within the 'box - she's been up on ramps with the rear wheels jacked - but its hard to say whether its bellhousing or 'box itself.
Anyone with experience have any idea how long to remove and replace a gearbox ??
>> Edited by SotonS2 on Thursday 4th August 08:49
Last week it took a bit of turn for the worse and this morning was no better. No choice, 'box out and either rebuilt or replaced before SCH. I can't run the risk of it failing completely during a spirited run to Silverstone. B***ox.
I haven't a clue what has gone - the noise is a heavy 'clunk' which is slightly worse when the car is coasting in neutral and the transmission is not under load. It's rotational and there is one 'clunk' per turn of the prop shaft. Because of this, its more noticeable at low speed.
Its definitely coming from within the 'box - she's been up on ramps with the rear wheels jacked - but its hard to say whether its bellhousing or 'box itself.
Anyone with experience have any idea how long to remove and replace a gearbox ??
>> Edited by SotonS2 on Thursday 4th August 08:49
Neil,
Are you sure its not the diff end UJ?
This went on mine last year. Started off as a quite muted 'knock' then got progressively worse. As you say, it eased off in neutral/on the overrun....ie without any load on, then came back as you put power down.
Luckily had the car booked in to Austec for springs/dampers and they tracked it down. I was thinking along the lines of CV joints initially - but it wasn't so.
If it is gearbox, then its worth doing the clutch at the same time....EEEK!
Nick
Are you sure its not the diff end UJ?
This went on mine last year. Started off as a quite muted 'knock' then got progressively worse. As you say, it eased off in neutral/on the overrun....ie without any load on, then came back as you put power down.
Luckily had the car booked in to Austec for springs/dampers and they tracked it down. I was thinking along the lines of CV joints initially - but it wasn't so.
If it is gearbox, then its worth doing the clutch at the same time....EEEK!
Nick
nawarne said:
Neil,
Are you sure its not the diff end UJ?
This went on mine last year. Started off as a quite muted 'knock' then got progressively worse. As you say, it eased off in neutral/on the overrun....ie without any load on, then came back as you put power down.
Luckily had the car booked in to Austec for springs/dampers and they tracked it down. I was thinking along the lines of CV joints initially - but it wasn't so.
If it is gearbox, then its worth doing the clutch at the same time....EEEK!
Nick
Hi Nick,
I'm 99.9% certain its not the UJs - that was my first (optimistic) thought. Mine is actually worse in neutral and gets better when the transmission is loaded. Added to which, the 'clunk / knock' is there all the time, on every turn of the prop - even with the back wheels off the deck, in 1st gear and on tickover.
As far as I could tell when clambering under the car, the noise is coming from very close to the clutch plate. Best case it is some part of the clutch that is disintegrating. Worst case, bin the 'box and source another one.
Its going to be tight for SCH....
According to the Bible you can drop the gearbox out from underneath and there is a description of how to do it.
I've never done it but I suspect it's a right bugger unless you've got access to a pit or post lift. Trying to ease the gearbox far enough back to seperate the gearbox from the engine whilst at the same time supporting it sounds like a bugger. And trying to line it all up to go back in?????
I agree with Nick the propshaft UJ's are a prime candidate. As you are going to have to drop the exhaust anyway have a good look at the UJ's front and back on the propshaft. The front one get's all the heat from the exhaust and unless the exhaust has been dropped it's unlikely to have been greased. There's a place in Feltham that did a good job balancing mine (turned it round in 24hrs). They will do a complete re-con job as well.
propshaft Services
Central Way North Feltham Trading Estate
Feltham Middlesex
TW14 0RX
Tel: 020 8844 2265
Just of the A312 on the trading estate opposite Tesco's.
Colin
I've never done it but I suspect it's a right bugger unless you've got access to a pit or post lift. Trying to ease the gearbox far enough back to seperate the gearbox from the engine whilst at the same time supporting it sounds like a bugger. And trying to line it all up to go back in?????
I agree with Nick the propshaft UJ's are a prime candidate. As you are going to have to drop the exhaust anyway have a good look at the UJ's front and back on the propshaft. The front one get's all the heat from the exhaust and unless the exhaust has been dropped it's unlikely to have been greased. There's a place in Feltham that did a good job balancing mine (turned it round in 24hrs). They will do a complete re-con job as well.
propshaft Services
Central Way North Feltham Trading Estate
Feltham Middlesex
TW14 0RX
Tel: 020 8844 2265
Just of the A312 on the trading estate opposite Tesco's.
Colin
No pit - no post lift. Yup, it'll be a bugger 
I'll remain optimistic as long as possible on the UJs
I should be able to whip the prop off tonight and, if necessary, get it inspected before I commit to dropping the box out. Thanks Colin for the details on the prop re-furber. I'll be delighted if that's all that is required.
If the box does need to come out, I was almost considering hiring a hoist and lift the engine and 'box out as one. That always was my plan at some point (to get chassis and engine painted) but with SCH only 10 days away that's a non-starter....
>> Edited by SotonS2 on Thursday 4th August 10:25
I'll remain optimistic as long as possible on the UJs
I should be able to whip the prop off tonight and, if necessary, get it inspected before I commit to dropping the box out. Thanks Colin for the details on the prop re-furber. I'll be delighted if that's all that is required. If the box does need to come out, I was almost considering hiring a hoist and lift the engine and 'box out as one. That always was my plan at some point (to get chassis and engine painted) but with SCH only 10 days away that's a non-starter....
>> Edited by SotonS2 on Thursday 4th August 10:25
According to the bible it is just possible to remove the box on some cars from underneath. Personally there was no way it was coming out from mine and I tried for long enough. Even with the body off it was impossible unless you grind bits of the casing away ! Would hate to think about lining it back up to go in.
If it needs to come out then would recommend your suggestion to remove engine first or engine and box as one unit. Get a good strong hoist as the engine alone is rather heavy. Good luck with it.
If it needs to come out then would recommend your suggestion to remove engine first or engine and box as one unit. Get a good strong hoist as the engine alone is rather heavy. Good luck with it.
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