Gearbox oil level investigation

[Gazza]

As posted a while back my gearbox started making bad noises so I decided I would take it out and strip it. Its been an off/on job but finally got it out last weekend. I did it on the drive by myself (20 year old son nowhere to be seen!) with the front end on axle stands. I found it straight forward enough. I removed th transfer box first to reduce the weight.Most awkward bits were removing starter motor top bolt and bell housing top bolts (not looking forward to putting them back in).
With the gearbox opened up thought I would investigate the oil level issue that gets mentioned. I have read its the layshaft bearings that make noise due to them being starved of oil, thats not the case as they are at the bottom and fully submerged in oil. Its the driven/drive shaft bearings that are only just in the oil if the box is filled to the fill plug level.

First time I've tried inserting photos so hope this works.

First image shows bell housing on inside, you can see fill plug on the right, if you look down to the driven shaft bearing housing it is very close to the fill level:

I set the gear assembly level on the bench and measured about 12.5mm to where the oil level would be:

The measurement to the bottom of the bearing is 13.5mm ??

The measuring is not that accurate but it does show the oil level at the fill plug is to low to give good lube to the drive shaft bearings (especially if you are going up steep hill)
Hope this is of interest and it does prove that the gearbox need that extra oil putting in.

 

[dave123]

As posted a while back my gearbox started making bad noises so I decided I would take it out and strip it. Its been an off/on job but finally got it out last weekend. I did it on the drive by myself (20 year old son nowhere to be seen!) with the front end on axle stands. I found it straight forward enough. I removed th transfer box first to reduce the weight.Most awkward bits were removing starter motor top bolt and bell housing top bolts (not looking forward to putting them back in).
With the gearbox opened up thought I would investigate the oil level issue that gets mentioned. I have read its the layshaft bearings that make noise due to them being starved of oil, thats not the case as they are at the bottom and fully submerged in oil. Its the driven/drive shaft bearings that are only just in the oil if the box is filled to the fill plug level.

First time I've tried inserting photos so hope this works.

First image shows bell housing on inside, you can see fill plug on the right, if you look down to the driven shaft bearing housing it is very close to the fill level:

I set the gear assembly level on the bench and measured about 12.5mm to where the oil level would be:

The measurement to the bottom of the bearing is 13.5mm ??

The measuring is not that accurate but it does show the oil level at the fill plug is to low to give good lube to the drive shaft bearings (especially if you are going up steep hill)
Hope this is of interest and it does prove that the gearbox need that extra oil putting in.

can't see any pics ?

 

[Gazza]

Try again.

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[malin]

Can we not just overfill the box by say tilting it to the ns then filling it or would this too cause damage to the box?

 

[solarman216]

I do not consider it would make any difference, as soon as the first motion shaft is rotating the oil is picked up and thrown around all over the box so everything is adequately lubricated, what is important to remember is if the vehicle is being towed for any distance the above does not happen and bearings at the top of the box can be running dry, Rick

 

[solarman216]

Anyway what did you find regarding the noise issue? Rick

 

[Gazza]

There was no filings at all in the gearbox and bearings that can be got at don't feel rough turning or have any play.

this is what I found when opening the transfer box:

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The chain has actually broken in to two pieces, and there are a lot of loose links and metal fragments.
I have only tried 4wd a couple of times and that was only on wet grass / mud for a few minutes so I cant explain how its broken unless it was like it when i bought it. Going to strip it down further to see if filings & chain links have got into a bearing in the back part of the transfer box.

 

[solarman216]

Ahhhhhhhhh very interesting, so it could be the transfer box making all the idling noise, that would explain why mine has got no worse over 30k miles as I like most others rarely use 4 wheel, no hang on a minute the transfer box is not turning unless 4 wheel is engaged, so not the case, cancel the first comment, Rick

 

[Gazza]

When 4wd is selected it engages the gear that drives the chain but there are still gears and bearings revolving when 2wd is selected as drive from the gearbox still has to go through the trasnfer box to the rear prop shaft. This is the part of the transfer box I will strip next

 

[solarman216]

When 4wd is selected it engages the gear that drives the chain but there are still gears and bearings revolving when 2wd is selected as drive from the gearbox still has to go through the trasnfer box to the rear prop shaft. This is the part of the transfer box I will strip next

Wait to here, Rick

 

[Lazy-Ferret]

Just found this... what was the outcome in the end, was/is it the transfer box making all the noise?

 

[Banshee]

I came back and searched for this because of Alex's comment in another recent thread, just bumping this up to the top again so everyone can see the pictures