Roamerdrive (Defender) noise

[Northwards]

I do wonder about tolerances. I measured once, twice and thrice and I couldn't get a 3mm clearance - about half that, maybe 2mm at most - which is when I started to get concerned about the inside of any oil fitment fouling the nut. 

Have I got them pressed together yet!? 😎 Afraid not - I only picked those parts up this morning and though I'm supposed to be on leave I needed to be in the office. I'll see if I can manage that tomorrow morning before heading off for the weekend to work on 'my' other Defender. If not, then I'm off all next week and would definitely get it done then. 

How are your temperature stickers holding up? 

[Peaklander]

I haven't looked for these last 10 days since the short high speed 😀 run the other weekend. I will get chance over the next few days and post them up on here.

The nut isn't at the end of the shaft though and it isn't as wide as the bearing, so there is room but what you have done is much better - 'future-proof'.

[Northwards]

That's a handy pic. Even with the nut in the vice, and my turning the shaft by hand (where there's lots of grip on the gears) the nut on mine doesn't go that far down. 

If I haven't already I'll make a point of taking a pic of that during the "final push". 

... and it's worth remembering that although the nut isn't as wide as the bearing it's also rotating, so the clearance is only from the 'corners' of the nut to the inside of the casing. 

[Peaklander]

The protrusion depends on the position of the synchro hub along the sun shaft. I replaced my sun shaft and so this position had to be chosen when pressing the hub on but I think Ray had advised me to put it in the middle of the splines. If it is further back (not pressed as far), then there won't be as much clearance. Hmmm.

 

 

[Northwards]

Yeah - I'll need to see if I took any pics of that specific spot before removing the nut and bearing, but my synchro hub hasn't been touched. There was no need, so it's still in the factory position. 

But if there's a difference, it is only 1mm.

 

[Peaklander]

To remove the bearing, the puller was put behind the hub and they came off together. I don’t know if there would have been a way to pull the bearing without moving the hub.

Here’s a pic of the bearing being pulled the second time, when I wanted to get the bearing seal removed from the other face.

So it might well be that your hub was removed and replaced too, potentially changing the clearance at the nut  

[Northwards]

Thanks for posting those pics. I have to say even though "it is only 1mm" I was a little concerned that I might be rebuilding the unit with something fitted in a slightly different place so I checked my own pics. 

This is the sun shaft on removal. The circlip has been removed from the shaft in this pic, but you can clearly see that there is a small bit of the splines showing below the circlip ring. 

This is it on rebuild, and although the circlip is in place, you can see that there's the same small amount of spline showing. 

I'm as confident as I can be that this gear is in the same place on the sun-shaft as it was when I took it apart. I wonder if the workshop I used got a puller in under the carrier plate and left the gear untouched? 

 

[Northwards]

Now for the rest of the rebuild of this unit. 

As before I'll try not to use any pics that Peaklander has posted above, and try and add those which I think might contribute to the overall knowledge of these OD units.

First step was to clean the rear casing. I'm not in any way familiar with the inside of gearboxes, so maybe this sort of brown discolouration is entirely normal, but I had wondered if it suggested some heat issues with the oil 'burning' onto the outside of the case??

After cleaning - as you can see, I decided not to use the dishwasher... 🤠 Even after cleaning there was still this residual discolouration - green circle. This is at the very rear of the unit, in the location least benefitting from any oil flow. 

I also carefully drilled out the three receiver holes, where the pins on the sun shaft carrier go. Not to make them any larger, but simply to remove some metal where the aluminium casing had 'picked up' during initial assembly. (yellow circles). The 'steps' you can see in these holes are original, and I guess intended for the alignment pins to butt up against. 

Next step was to press the sun shaft and synchro assembly into the rear casing. I think I said that in the time since taking this OD apart I've bought a hydraulic press for the garage. Loving it! I've already used it a lot and using it to press the various parts of the Roamerdrive together made the whole thing very easy.

Looking from underneath here, I used longer bolts up into the sun-shaft carrier just to be sure that nothing would twist out of line under the press.

Then it's on to the fun and games with the shifter plates/synchro slippers, and a further thanks to Peaklander here for posting up the instructions .pdf.

The inner spring in the correct place - in fact I did have to pull out the first slipper a couple of times as this spring kept moving round (anti-clockwise in this pic). The newer shifters are supposed to be a better design, but don't have any sort of 'receiver' in them to hold the spring. So by the time I got the first slipper in place properly, the spring started a little to the right from its location in this pic. 

Slipper in place - very poor/pointless pic, but the spring is down there. 

I have to say that the rest of these I found pretty straightforward. I had more of an issue getting the second spring to sit into the hub without pinging away. 

On to the forward part of the casing. I raised the question above about the hole in this casing that corresponds with the oilway in the transfer box casing. That one (sorry no pic at the moment) is a whopping 16mm - the one in the RD casing is 6mm... If it's so important in terms of oil flow into the unit, I couldn't see any good reason not to try and open it up a little.

I went from 6mm to 8.5mm in 0.5mm increments (green circle) and stopped before this hole infringed on a lip in the casting (yellow line). I am conscious of the casting failure pics that Snagger posted above, but I think there are other weaker points than this. Whether it will make any material difference to the oil flow, who knows.

One thing I had noticed on this casting are clear movement/witness marks. This is where the outer ring of the largest bearing sits. 

I can't imagine that this bearing is intended to spin inside this housing (though the replacement above was a very easy press into place) but I'm fairly confident the original bearing in this location was out of spec. Hopefully this new one will be quieter and "better behaved"!

Re-assembly! These parts haven't been together for more months than I'd hoped for, so it was nice that they slotted together so easily. Like Peaklander I chose to put the two "loose bits" that could fall out (the pin roller bearing that goes onto the sun-shaft, and the other synchro baulk ring) into place in the back casing, and then lower the front one into place. The O ring did need a lot of vaseline to hold it, but it all snicked together very easily. 

I thought I'd comment on the oil levels within the unit. The yellow line above shows part of the front casting/casing that must act as an 'oil dam'. When the unit's at rest, any oil above this level will just flow back into the transfer box. Note also the white marker pen in the green circle. 

Looking at the unit from the side (and in this pic it is properly level as it would be installed):

You can see the white marker scribble, showing the level of the 'oil dam', and the black line tries to show this oil level along the unit. You can see that the rearmost, smallest bearing casing (green line) is above this oil level, though the bearing races themselves would hold some oil in there. On the other hand, as we shouldn't use the OD from initial start-up, I guess oil would be splashed around more until we got up to 'cruising speed' and engaged the OD?

I did check it was all working... 

Overdrive disengaged, and one rotation of the input shaft (the inner, splined one) gives one rotation of the output shaft - white dots:

Overdrive engaged and the same one rotation of the input shaft gives a much greater movement of the output shaft - just what I'd expect though I'm aware that someone much cleverer than me could come along and burst my bubble!

And that's it.. ready to go back in.

I'm off to fit this now, along with the modified sump. I'll not get the car moving for a couple of days yet, but at least this will be a big part of the job out of the way. 

Final thanks to Peaklander for taking the time to trailblaze and post such a good set of pics for me to follow. I might have been able to do this myself, but it was a whole lot easier with someone else's experiences to follow. 👍👍

 

[Snagger]

I don’t think that drilling will be a significant weakness - it’s much smaller than the bolt hole drillings through similar section material.  I still think the small locating tabs are very weak and the side slots too big.

I believe the brown deposits you are concerned about are the sulphur in the EP90, which is what gives that oil the EP protection.  It’s normal when running EP oils, regardless of temperatures attained.

[Peaklander]

On 4/6/2023 at 8:04 PM, Northwards said:

How are your temperature stickers holding up? 

They are in the box that is shows them at around 93C - so far so good.