Oh god what have I done.

When I got my landy the overdrive screamed like a banshee when it was engaged. When not engaged it was totally quiet. To get out of it you had to double clutch. Eventually, it broke completely and wouldn't engage at all but it still worked fine when not in use.

Today, I decided to see if I could get it working again. I started off taking it quite slowly and keeping order of everything but at one point the internals basically all fell out. Now I am left with loads of bearings/gears/other bits and no idea what to do with them.

Apparently the clutch sleeve is a common thing to wear but errr... I don't seem to have one of them. A couple of splines on the input shaft and the syncro teeth look a bit worn but apart from that it looks ok to me.

I was thinking about getting a high ratio transfer box a while ago and maybe I should just do that instead of trying to fix this thing as the parts seem to be crazy expensive to replace anyway. As you can tell I haven't taken apart any gearboxes before..

I would go the high transfer box route if it were me, you would still need to source a back plate for the gearbox and the replacement cog thingy that you take out when you install the od if the previous owner didn't pass them on

I cleaned up the parts today and quite a few would need replaced. Parts seem so expensive for it that I don't think it's worth it really. I am trying to source the cog/cover that the o/d replaces but no luck so far. I looked on ebay for them a while back and saw a few but can't remember what I searched for.

I think its an input gear? But Im not sure. Just search for overdrive and it will come up usually.

Some good info here
http://www.nickslandrover.co.uk/overdrive-overhaul/
The clutch sleeve is the part fastened to the rear of your gearbox mainshaft.

Worn bearings are what make these noisy.

You can get all the bearings at low cost if you use the bearing numbers and not LR part numbers. I rebuilt mine earlier in the year, total cost of bearings was ~£80, I also replaced the main shaft, and input coupling £140, and £60 respectively. I now have a nice to use and quieter overdrive.

The input coupling is what seems to be referred to as the clutch sleeve, this is the wrong name. This part is the bit that bolts to the output shaft of the main gear box and does not come away with the overdrive when you first remove it. You'll need a special tool to remove this part as the nut that holds it in place uses a spline drive rather than a hex. It's tightened to ~80LBs/ft

This is my home made version of the nut tool, others are for sale on Ebay around the £80 mark


This shows the nut in the tool with a 30mm socket on the back of the tool.


I do not know why people think they are the weak point in the gearbox, I run a 3.9 V8 in mine and have done for over 15 years with that same overdrive. Gearboxes fail before the overdrive does, great bits of kit, and unlike the high ratio transfer box, it's selectable.

While mine was all in bits I decided to draw it all in Solidworks so I had a future reference for all the parts.



I just need to complete this with a labelled exploded diagram of the thing.


The best guide to rebuilding and repairing the overdrive I've found so far is:
http://www.lrsoc.com/forum/forum_files/Overdrive Repair and Service Manual.pdf

This will also give you all the bearing numbers etc.

Rather than an expencive h/r gear for the box...you could do what I did....fitted 3.5/1 diffs front and back...out of an early disco or RR...give the same gearing as an overdrive in high.

As with the h/r box...if you have an old 2.25d it will struggle.

Knocks your speedo out as well...I got around these probs...had my o/d in for 35 years from new....but glad to see the back of it.

I run with a 200di.

Nick.

If you decide to get rid of it let me know and I can add it to the ever expanding pile of stuff to fix on mine.

nickjaxe said:

Rather than an expencive h/r gear for the box...you could do what I did....fitted 3.5/1 diffs front and back...out of an early disco or RR...give the same gearing as an overdrive in high.

Click to expand...

I should have added I'm also using 3.5/1 early rangerover diffs as well as the overdrive.

Gee what engine have you to pull those????

could be why your od is toast

nickjaxe said:

Gee what engine have you to pull those????

Click to expand...

3.9 EFI Serpentine V8