R380 cross drilled gear thingamybob

**Utemad** · 11th September 2006, 09:02 PM

From reading this and elsewhere I think the Disco has the 1.222 ratio. How do you rotate the intermediate gear?
I thought I would copy all this info here as it is most helpful I think.

This is interesting. It describes the problem I am having.
http://www.fourfold.org/LR_FAQ/Disco/Disco.clonk.html

This is from http://www.ashcroft-transmissions.co.uk/faq.html#a28
I want to change the input gear on my LT230 for a later cross drilled type, can I do this in situ or do I have to take the transfer box out? This is only available on a suffix C or later (last number of transfer case), it cannot be changed on Suffix A or B transfer boxes. On a 1.667 or a 1.410 removal of the gear is simple, it just slides out; on a 1.222 it in necessary to rotate the intermediate gear to a position where the teeth on the middle and rear gears are in line and allow the input gear to slide through. It is not possible to change a 1.003 in situ.

I have a Tdi 90 and it "clunks" when I take up drive. Why? The most common cause is worn mainshaft spline but other things to check the A frame ball joint and the halfshaft drive flanges, especially if you have a 300 tdi Defender. To check mainshaft spline wear remove the PTO cover and with the main box in first gear rock the car backwards and forwards whilst looking into the end of the input gear. If the spline is worn you will see movement of the shaft in relation to the gear. Replace the gearbox and transfer box input gear (use a cross drilled gear to prevent recurrence of the problem).

I am familiar with the much talked about mainshaft wear problem on my DefenderDiscovery but I don�t know how bad mine is, or if I need to look at replacing my gearbox? The best way of ascertaining the degree of wear is to chock the two front wheels, handbrake off, mainbox in first and jack up a rear wheel. Remove the PTO cover to the left of the handbrake and you will be able to see the gearbox mainshaft in the centre and the transfer case input gear around it. By rocking the handbrake drum you will be able to rock the gear around the shaft thus getting some idea of wearbacklash between the two.

**Bush65** · 12th September 2006, 05:58 PM

Originally Posted by Utemad

...How do you rotate the intermediate gear? ...

Put the gearbox in neutral, jack rear wheel/s so it is clear of the ground, then rotate the brake drum.

The intermediate gear meshes with the input gear and the output gears There are 3 gears on the intermediate shaft. 2 large dia gears for input and high range and a small gear for low range.

These 2 large gears have different numbers of teeth but there is one position where the tooth space on one is inline with the tooth space on the other.

In your case (1.22:1 high range), you need to rotate the t/case gears so that these 2 inline tooth spaces on the large intermediate gears are aligned with the meshing tooth of the intermediate gear. Then the input gear can slide out of the PTO opening.

If the splines in the input gear are worn, you will also have to replace the gearbox mainshaft, if manual gearbox or the spud shaft if auto box.

It is necessary to remove manual gearboxes to replace the mainshaft but the spud shaft can be replaced through the PTO opening.

**Utemad** · 12th September 2006, 07:54 PM

Thanks for the info. I would still like to remove the gear to check it out but I cannot see any play between the outer input gear and inner mainshaft.
There is plenty of oil in the area so I assume it is lubricated.

**4bee** · 12th September 2006, 08:52 PM

But if there is a buildup of crud on the shaft/gear you wouldn't notice any play, ample lubrication notwithstanding.

**Utemad** · 12th September 2006, 09:03 PM

There didn't appear to be any crud on the end of the gear. I could see the end of the gear and the end of the mainshaft inside of it. Both turn in unison with no backlash.
All appeared to be good.

**4bee** · 12th September 2006, 09:08 PM

When it comes out there would normally be a thick sludge on the gear if it's not getting lubricated properly. There was on mine when I removed it when fitting the Oil Feed Plate & it seems to be the norm according to Steve Parker UK who make the plates.

**Utemad** · 12th September 2006, 09:14 PM

So when you pulled off your cover you couldn't see the gear for the sludge? Mine was there for all to see.

**4bee** · 12th September 2006, 09:18 PM

No. After you pull the gear, then you can see any sludge.

Gear should come out ok when you take any load off it but be careful. It's a bit heavy & has sharp edges. Wear gloves.

**4bee** · 12th September 2006, 09:25 PM

Google can't open his website as well.

Since you have gone this far, imho, it would still pay to remove & inspect the gear. Then at least you will know what you have. Crossdrilled or not & give it a clean if it's not.

**Utemad** · 12th September 2006, 09:27 PM

OK thanks. I might give it another go tomorrow night.
Fun fun fun.

Thread: R380 cross drilled gear thingamybob

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