Impossible gearbox/transfer box whirring...

Hi

I know that Land Rover gearboxes like to make a little noise - but my one is really going to far. The best discretion is the noise you get when reversing hard in some cars - that whirring noise. It kicks in at 25MPH and then gets louder and louder.

You can also recreate it by putting the transfer box in to neutral - and revving up.

In low ratio it happens at a lower speed.

Pressing the clutch makes no difference.

It tends to be worse under load.

It is an R380 Gearbox from 1996, but an original 1989 transfer box. The gearbox has been changed - but it didn't fix the problem.

Most of the bearings on the transfer box are new.

My guess is that it is the input gear in the transfer box - but can this gear make this noise? And will getting a replacement one from Ashcrofts fix teh problem?

I know that I really should live with it - but I have been doing for almost a year now - it it means we do no long journeys in the 110 and conversations just can't happen. I am also worried that something worse might happen.....

Any ideas or thoughts?

Thanks,

Henry, Exeter.

did the clutch release bearing and carrier get changed when the box was swapped ?

Yes, new clutch (and associated bearings).

The clutch operation makes no difference to the noise. Clutch in, clutch out - it just wines.

Henry

Might be worth checking the release bearing as he says. I had a similar problem and the bearing made a noise when in or out because it was knackered and did it's own thing. Sometimes they do not get changed when a new box goes in. Also, check your output flanges on the t-box. Chock the vehicle wheels and stick her in neutral (engine off of course). Get underneath and grab the props. They should rotate, but they should NOT wobble at the ends where they meet the diff or the t-box - this could indicate either done prop UJ's or flange bearings. Flange bearings can make whining noises when they are on the way out.

Hi

The release bearings were certainly done - so we can rule them out.

I know it is not the wheels/prop shaft etc, as it does it when the transfer box is in neutral - so the propshafts, diffs, output flanges, wheels etc are not turning.

I think it is the input gear - it's the only thing it can be if we know the noise happens when the transfer box is in neutral AND it isn't the gearbox or clutch.

Has anyone else ever had this noise from the input gear? Could it be a pre-load issue?

Henry

No taking the p-ss here but have you listened to each unit to narrow down the culprit sound? I use a large screwdriver and stick my ear hard against the handle and the other end on the gearbox or t box. Firing a new g box into an old t box may bring a worn input gear problem to the fore as original input/output gears tend to wear into each other over time and may not make a wear issue obvious. I had a Disco t-box recently with less than 100k and it looked great but the input gear was dire and I scrapped it for parts.

Hi

It was already making the noise before the new gearbox went in - the gearbox had other issues (syncro not effective) so I thought I would change it - I thought it might also cure the noise issue - but that would have been far to easy.....!

Henry

T box can be changed in a few hours with two fellas and at least one who has done it before. You probably don't want to hear that - either did I when had a nasty noise in my unit :-(

I had this issue on mine:

I had an disco transfer box that the 3rd diff had gone in and the 1 on the defender had a leak. The disco tb was stripped down and the 3rd diff out the old box put in.
Everything was checked (bearings and gears and teeth).

All was put back together and I have a whine (as you say gets loader as you go faster).

It can be down to a few thing like and gears that had been replaced previously could have been swapped with "patern" ones that were not crowned (the chamfers on the teeth to expel air out as the teeth mate and pass over one another - hence the whining is air noise) This is in the Q/A sectionon the Ashcrofts site.

Also as you are using 2 different boxes (gearbox and transfer box) from different sources therefore different ages and at different wear stages in their life - you have now mated up (possibly) 2 slighlty different gear shapes (because of the wear) this will now create a different noise as different parts of the tooth are touching and also the air noise will be different as the air will be expelled out between the teeth differently.

I know mine was ok because as I said it was checked before we put it back in.

This could be a couple of reasons behind your whining noise.

A bit long winded (no pun on the air expulsion) I know but I hope it has helped.

SpenB

if it is a std 1410 t box you can remove input gear by removing the rear cover plate ,then run gear box it will rule out or in t/box also see if intermediate cluster gear has play with screw driver at same time,when t/box is in neutral all gears are still been driven but not locked to diff

Hi

I am going to take out the input gear next weekend and see what it looks like. I'll run it with the gear out and see how it sounds.

Henry