Hi all

Going down motorway at 70MPH maybe more sometimes, ease off throttle and it jumps out of 5th gear, Doen't do it every time, just now and again. More on a long trip.

Also agian only sometimes when I pull up (Slow down and stop) I got this very small Notchy noise from the rear and you can sort of feel the back of the car notch on it. (Move Down)

Any Idea's, Thanks

Our Mechanic is not in today, so posting it on here

 

Possibly ' The Big Nut' loosening at the rear of the gearbox mainshaft where it holds 5th and reverse on out side the main case. That would explain the occasional noise and the occasional drop out of gear.

It is possible [ with a bit of fiddle ] to separate the rear housing of the back of the gearbox and check / tighten the nut without removing the whole box.

Best I can offer as an online diagnosis.

David API

 

I think David is right. I had this on my MY 2000 UK turbo. Took it to a dealer who fixed it in 20 mins, so the fix must have been external to the box. Never faultered again.
911

 

If you find out what notch sound is at back will you let me know, mine is same, dealer thinks it is a bush, but is not sure. Have also been informed that 5th gear nut can loosen and can be tightened with box still in car.

 

Another vote for a loosened mainshaft retaining nut, although could be worn synchro/springs if the car is older than MY99. As David says, the 5th/reverse package can be accessed with the box still on the back of the engine, but it's difficult to do the job right this way. Far too much risk of dirt finding its way in.

Your car can't have been suffering the problem David described if the fix only took 20 minutes. Tightening the input shaft nut at the very least involves removal of the gearbox mounts, linkage, propshaft, probably downpipe, and the transfer case. Even a team of trained rally technicians wouldn't do all that (and put it back together) in 20'.

 

They are good at Andrew Burts!
All I remember was that it took a very short time to do as I was expecting a box out job. Whatever Ken did it was perfect afterwards! It did not have the other problem mind.
911

 

[QUOTE=greasemonkey]Another vote for a loosened mainshaft retaining nut, although could be worn synchro/springs if the car is older than MY99. As David says, the 5th/reverse package can be accessed with the box still on the back of the engine, but it's difficult to do the job right this way. Far too much risk of dirt finding its way in.

A modest amount of road dirt just helps the gears bed in a bit quicker ! - removes the high spots see !! LOL

David

 

Thanks for all the help.

What nut is it, any pics of where, etc.

And also why would I get a noise from the rear of the car, if it's the gearbox nut is not tight.

 

Have exactly the same problem with my MY00. Places I have tried already (PE, Quenby's) want to do a box out job and fit modified 3/4/5 gear hubs. Would be very interested in more experiences of fixes without the box out.

graham

 

David/CHEWM/911 - dealers who will try 'the big nut' fix without jumping straight in and stripping the box?

Riverdale - are you sure the noise isn't just the rear brake shoes 'grabbing'. Mine grabs with quite a clang and the back of the car drops if the handbrake is applied even if only barely moving.

Graham

 

I dont apply the handbrake,

I will be slowing dwon to a junction lets say, and when the car is almost stoped (1MPH) or have stoped then the car seems to clonk and sit down, The noise is now all the time but not always with the back of the car sitting down. It almost sounds and feels like a bush gone at the rear.

 

Not immediately sure why there'd be the need to replace the 3rd/4th hubs Graham, provided they're working alright. May just be a precautionary "we've got the box in pieces, let's do them anyway" type deal.

Apart from anything else, replacing the 3rd/4th package would require full disassembly of the gearbox, whereas 5th/reverse only needs the transfer case taking off the back.

This can be done with the box still on the back of the engine, but, as mentioned above, in my view there's too much risk of dirt from the underside of the body finding its way in. IMO the best way to do it is with the box off. Apart from anything else, you can get a proper eyeball at the bits, which, in my case, alerted me to a problem I wouldn't have seen if I'd tried to do it all underneath the car.

 

When Andrew Burt's did my car, it was only about 10K miles old, it was a Company car, and I needed it back ASAP so waited for it.
Fix was permanent.
911

 

I think our mechanic is having a look tomorrow for me. It's jumping out of gear more and more now, Twice yesturday, and the noise is all the time now as well.


Any one know a guide of where this nut is.

 

The nut in question is on the back of the gearbox input shaft. To gain access your mechanic will need to either drop the box down, or, better, remove it from the car completely. He'll then need to unbolt the transfer case and slide it off the back (disengaging the selector arm as he goes), after which the input and output/front diff propshafts will be visible.

A 35mm thin walled socket is needed to tighten the nut, although before doing so, he'd be well advised to remove the entire fifth gear and synchro package and make sure there's no damage been caused to them. If the nut has been loose for a while, the synchro cone and hub can pick up against each other, with the heat often cracking the hub. It's worth making sure it's 100% before putting the whole thing back together...

Also make sure he degreases and threadlocks both the end of the shaft and the retaining nut before tightening and restaking it. Tightening torque is 87lb/ft.

 

As a direct result of this thread I cancelled my booking for a gearbox rebuild and instead had Quenby's just tighten the 5th gear nut (£300) saving me alot of money. Picked it up tonight and no more problems! Thanks very much to everyone here - beers are on me if ever you are in East Herts.

Graham

 

I don't know if the geometry of the rear suspension is right for this but.....

Maybe the rear shoes (handbrake) or callipers are slightly siezed. Enough to grab, let go at low speeds or at least to not modulate the braking force smoothly.

Vindaloo.

 

Did they literally just tighten and restake it Graham? The belt and braces approach is to whip it off, degrease both it and the end of the shaft, and then reapply with a good sturdy threadlocking compound before staking for good measure.

Proof of the pudding will be whether it stays like that, but if they've done the job right, it certainly should do!

Hmmm, in West Herts/Bucks quite a bit. Where's your local?!

 

New locknut (802622020) @ £11.42 + VAT.

 

Cool. £11.42+ VAT though? That's the old (pre-reduction) price. They're £10.90 now. You've been conned sir!