Building the gearbox of my dreams

Been enjoying this chap

Me to! Do you mind saying where you bought the Roamerdrive unit? Was it through Ashcrofts? Come April I'm hoping to spend a bit of tax rebate money on one, and an Ashcroft atb in the rear axle! Great thread!!

Gentlemen, thanks for your good wishes. I'm flattered. Mr Gottschalk, I bought the Roverdrive/Roamerdrive from Rocky Mountain Spares. The limited slip centre diff was from Ashcrofts.

Well, today was spend finishing off and fitting instruments. I've filled the transfer case and overdrive unit, and started up, and selected gears, watching the brake drum spin at different speeds. Not going anywhere, because I wanted to give it a run with the propshafts off to see if it was working So far so good. Then I got busy fitting the instruments. Guess what came in the kit with the rev counter:

Scotchlocks. Or not Scotchlock brand, but some kind of self-piercing clip-on connector. I didn't use them because I wouldn't be able to hold my head up on Landyzone ever again. So instead I used things like this:

It's an insulated three way spade terminal connector. I took my time and put a dab of solder on all the crimp on connectors where they join onto the wires. No matter how carefully you crimp, the amount of vibration on a Land Rover means that they'll come loose sooner or later. So I soldered everything I could. Eventually my instrument cluster looked like this:

I always think it looks really sad when you're at this stage in a wiring job. However it soon started going back together. At length the instruments looked like this:

Not entirely plain sailing, because the light wouldn't come on on the oil temperature gauge. It seemed to be something to do with the bulb holder. it would work perfectly in my hand, but when inserted into the gauge and screwed down to the dash it went off. Eventually whilst fiddling with it I fused all the lights because I forgot to switch off before poking. Anyway, we're all back on now, plus propshafts on, floor pans, transmission tunnel and seats back in, so it's almost a complete Land Rover now.

Going for a little drive revealed something interesting. It moves sometimes, but only when it feels like it. It is as if something is jumping out of gear. It can be encouraged to move again, but only after lots of waggling the levers back and forth. It's dark now but I'm wondering whether a bit of adjustment on the linkages is needed. Everything seemed to work on the bench, with the slider in the transfer box moving freely back and forth to engage the larger or smaller gear, and the overdrive seemed to engage with a fast and slow output speed when not in the vehicle. I've put the floor pan and transmission tunnel in, so they'll have to come out tomorrow. The speedometer is not registering, but that may just be that the multiplug on the new sensor isn't quite fully home. So more fiddling tomorrow.

I've been out this morning and some some investigation and adjustment. Took the mats out and got the transmission tunnel cover off. I think there might have been a combination of things. The transfer box high-low selector linkage may not have been getting the slider in the box quite far back enough to engage high. The rod from the new lever to the overdrive may not have been quite long enough and the lever itself was fouling on the various lobes and protrusions on the gearbox before getting the overdrive actuator on the unit itself through its full range of travel. I also noticed last night that I wasn't getting the difflock warning light. I found this morning that by moving the selector on the front nose cone of the transfer case I can lock the two drive flanges together and release them, so the problem's in the linkage and/or switches rather than the box itself. I've taken the speedo drive off and put it on again. I'm just having a cup of coffee and then I suppose I'd better give it a little drive to check out whether I've made any improvements. If I lose drive in the middle of the road at least the traffic is fairly minimal today, so I won't cause too much of a traffic jam.

sounds like just linkage adjustment ,i do it with 1 rear wheel up so you can turn hand brake drum to align gears and splines

jamesmartin said:

sounds like just linkage adjustment ,i do it with 1 rear wheel up so you can turn hand brake drum to align gears and splines

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Yes, that's what I'm hoping. I'll try it out in a few minutes and see.

I've done a bit more tinkering and had a couple of test runs. No loss of drive this time so I think it was just the position of the linkage. The speedo wasn't working, aside from a few twitches, and neither were the indicators, despite the fact that the hazards flashed. I worked my way through the fuses and found one that had not exactly blown but developed a resistance of about 80 ohms. Replaced it and the indicators came back. I tried the old speedo sensor on the cable, and could get a respectable 40 mph just spinning it with my fingers. To get the new one off, because there isn't much access, I had to take the handbrake off again. I think it may be that the little square drive male and female parts weren't completely seated together. Yes, even though it is electronic on the TD5, it still has a little square rotating drive as part of the mechanism. I put it back on and now we have the speedo working again. I have even seen the difflock light working, but it is intermittent.

Driving around with the transmission tunnel off is very noisy indeed. There's a bit of a squeak or scrape from the handbrake but I think that will lessen as the mechanism centres itself.

I've had an afternoon tinkering some more. I've had the difflock switch out of the front nose cone of the transfer case to see how it behaves itself. It works OK on the multimeter. Infinite resistance versus about three ohms when pressed. So what wasn't working? Eventually I ground out the threads so I could get it to sit a bit deeper in the housing and then it worked in time to the movement of the lever. Good. Another run with the transmission tunnel in place revealed the jumping out of gear problem again, especially when braking on the approach to junctions. Transmission tunnel off again and a bit more adjustment. I moved the mechanism round another couple of splines. I also think the foam soundproofing was pushing it out of gear. So on reassembly I pushed the foam well down inside the socket on top of the transmission tunnel. Another run, and all of a sudden the difflock warning light was on. I shoved the lever over to the right, but it stayed on. Not wanting to wind up the transmission too much I pulled in and jacked a wheel up. When the wheel broke traction with the tarmac it almost drove itself off the jack, there was that much stored energy. I spun the wheel freely and got the warning light off. I'll have to watch this - now that the transfer box lever is operating freely it is easy to move it by accident when I'm fishing around for the gear lever in the dark.
I got out on a bit of ring road to try the overdrive out. Checking the mirrors carefully in case there was a disaster and I stopped suddenly, I pushed the lever forwards. It's a bit notchy, even at speed, but in it went, and I was cruising at 50 with the engine doing a mere 1500 rpm. Quiet and relaxed. Just what I was hoping for. You've got to plan ahead a little approaching junctions to get it out of overdrive and into normal ratios to do your manoeuvring, but I'm looking forward to a long motorway drive. I was only in the 50 limit just now, so couldn't go very fast, but I'll get out for a longer run soon.

if switch is wound in too far it will start to jam diff lock selector switch is operated as selector travels under it ,there is no direct contact between selector and spigot linkage attaches too, its operated by spigot compressing a spring both in and out of lock, with the rear wheel up you should set linkage so that it fully goes into both hi and lo you should feel the detent as it does

Yes indeed, I've noticed this before. Plus it was pretty obvious when I had it apart - the yoke and slider for the difflock are operated by a spring, so if there's a bit of wind up the spring won't move the mechanism on its own. There's a positive action when I waggle things back and forth, and the detent balls are doing their job, it's just so free compared to what it used to be, that it's easy to knock it. I'm used to the transfer lever being almost immovable.

I've just been out for another run this morning and all seems fine. I took my partner to a large Sainsbury's on the outskirts of town. She's American so she loves supermarkets. She stocked up on orange-coloured oven to tableware which seemed to be reduced. We've already got more casserole dishes than we could ever use, but it makes her happy. Filled up with 1.03 a litre Sainsbury's diesel as well. The only thing that I can't get rid of is a persistent squeaky-scrapy noise from the handbrake. I've backed off the adjustment on the drum and on the cable but it won't go away. Last time I had this, I got new handbrake shoes and that cured it. So the present ones are only two and a half years old and hardly worn. Bugger. But the transmission seems to be working fine, which is the main thing.

Have you tried applying the handbrake while driving (on a clear road obviously). As long as you hold the button down and gently pull on the handle with a steady pressure it will just act as one big drum brake. May help to bed the shoes in again as they have been disturbed.

Kwakerman said:

Have you tried applying the handbrake while driving (on a clear road obviously). As long as you hold the button down and gently pull on the handle with a steady pressure it will just act as one big drum brake. May help to bed the shoes in again as they have been disturbed.

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Yes, I've been doing that. I even drove along with the handbrake on for a little while in the hope that warming the shoes up might help. I've pulled it gently, I've pulled it hard. I've ordered some new shoes now. The previous set came from Paddocks so they were probably Britpart. I've got some Pagid brand ones on order and we'll see if they do any better.

The handbrake shoes arrived this afternoon, so I went out and fitted them. They seem more nicely made than the previous ones I had on there. As soon as I jacked the car up it started to rain, so I spent quite a while wrestling with little springs under the car, with my wet fingers slipping. When I had finished I also succeeded in lowering the trolley jack on my nice new LED torch. It popped the lens out and cracked the body, but it still works. A bit of sticky tape should sort it out. While I was outside there was another delivery. A jiffy bag full of stainless steel screws and washers had arrived, so I can get my transmission tunnel fastened down. However, I'm not doing it this evening as it's piddling down and once again I have lost the light. A couple of other bits of troubleshooting needed include the fact that the left hand screen blower doesn't seem to be delivering much air, and the electric headlamp adjustment doesn't seem to be doing anything and the lights are pointing permanently downwards. Again, maybe something's got dislodged when I had everything apart the other day.

Anyway, the handbrake can now be adjusted to the proverbial three clicks, and doesn't make a squeaky-scrapy noise. I had a quick zoom up and down the road and all's well.

That's coming along nicely, Brown. Cruising along at 50mph, quiet and relaxed, just doesn't seem right! Must be fantastic and very rewarding Great job, mate!
I came in to look through my pictures to try and locate where an earth cable goes, but no luck yet. Just starting to rain here too, so I'll go back out and pack up.

More tinkering and testing today. I fastened the transmission tunnel down with stainless steel screws. I have carried on using the square plastic block captive nuts here, because you can't get to the back of them as the gearbox is in the way. My new torx head bung for the gearbox came too, so I removed the chewed up remains of the old one and put the new one in. I took the dashboard to bits (again) and investigated the lack of blower and automatic headlamp adjustment. The bit of flexible tube serving the blower vents wasn't properly seated, neither was the multiplug that goes on the back of the headlamp adjuster switch. All working now. I had a run up the motorway to test the overdrive out a bit more. I can cruise at 70 at a shade over 2000 rpm. The temperature gauge suggests that it runs quite hot and it was soon showing 100 degrees or more. It certainly smelled hot too. These things are known for giving the oil a bit of a hammering, according to what I've read online. So I might let it run-in for a few hundred miles and then give it an oil change once it has loosened up a bit. If you stop, it cools down pretty quickly though. The other thing that people say is that these units are a bit whiny. I think the sound has changed slightly, though added to wind noise, tyre noise and the like it is hard to say. I changed from normal drive to overdrive as often as I could and got a couple of occasions where it wouldn't go into normal drive. I've adjusted the linkage so it's a couple of turns shorter now so that may cure it. That's out of maybe thirty shifts over the course of today's driving. It's not a disaster - you just drive a little further in overdrive and try changing again later and it goes in. I hope this is something I can cure with adjustment and running in, because it could end up being a nuisance.

Although cruising is relaxed, that's pretty much all you can do! There's very little acceleration possible, so if you find yourself having to overtake or join a stream of slightly faster moving traffic in the outside lane you've got to drop into 'normal' to pick up speed. The engine isn't really into its main power band until you get to about 80 or so, but naturally I would never do something so dangerous and illegal on a public road. Of course. Taking your foot off the accelerator in overdrive feels like flying. You're not getting the engine braking effect because the wheels aren't trying to spin the engine so fast.

Thanks for your interest Mr A1203. It is indeed a real treat to drive quietly at speed. Hope you're managing to make some headway on your project despite the weather. Have you suffered much damage with all the heavy rain?

I'm sure you'll get the gremlins sorted soon. It will probably take a bit of getting used to changing your driving strategy. Everyday driving will probably not need the roamer, but for your road trips it will be very useful.

Yes, I'm making slow but certain progress. It's all the little fiddly things that take up so much time.
We live on a hill, so no damage with the heavy rain. Although I know a few people who are now out of their homes. Not too bad here in the North East though, compared to Cumbria and Yorkshire etc. Must be a nightmare for those folk.

The rain has been highlighting a few leaks on the Landy. There was a puddle on the rear wing in the tub. Traced it to a drip coming from a screw in the window (centre partition) took it out and applied bitumen based roof sealer. Should have sorted it.
I am also getting water lying on the foot panel, drivers side bulkhead. I was worried that it was windscreen seal or screen frame to bulkhead seal, but it is coming through the accelerator cable hole. Don't know why but I haven't fitted the cable to the pedal yet, but the rubber grommet around the cable should sort that out when I get around to it.

Al2O3 said:

I'm sure you'll get the gremlins sorted soon. It will probably take a bit of getting used to changing your driving strategy. Everyday driving will probably not need the roamer, but for your road trips it will be very useful.

Yes, I'm making slow but certain progress. It's all the little fiddly things that take up so much time.
We live on a hill, so no damage with the heavy rain. Although I know a few people who are now out of their homes. Not too bad here in the North East though, compared to Cumbria and Yorkshire etc. Must be a nightmare for those folk.

The rain has been highlighting a few leaks on the Landy. There was a puddle on the rear wing in the tub. Traced it to a drip coming from a screw in the window (centre partition) took it out and applied bitumen based roof sealer. Should have sorted it.
I am also getting water lying on the foot panel, drivers side bulkhead. I was worried that it was windscreen seal or screen frame to bulkhead seal, but it is coming through the accelerator cable hole. Don't know why but I haven't fitted the cable to the pedal yet, but the rubber grommet around the cable should sort that out when I get around to it.

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As I was underneath bolting my floorpans in this morning I noticed a steady drip of water coming from the passenger side. Round about the right place for the heater matrix, I thought. But it turned out to be water that had accumulated from Storm Frank (am I the only one who finds giving the weather names silly?) and I'd disturbed it. It's very difficult to stop water getting into a Land Rover. The main thing in my view is to stop it doing too much damage while it is in there. So I refreshed the Dinitrol along the edge of the bulkhead that the floor panels bolt to.

Yes, you need to drive a bit differently with the overdrive. The main reason I wanted one of these is that in normal drive, all your ratios are in exactly the same place. So unlike, say, converting to a 1.22 transfer box, I can carry on as normal round town, and just select overdrive when I've got a long straight-ish stretch. Of course, what I need now is a re-map to give me a bit more torque at low revs so I can make the most of all this high gearing.

More driving today and more changing between overdrive and normal. Seems to be working. No motorway driving, so wasn't able to check for temperature increases. I'm anticipating that the high operating temperatures will reduce a bit as things get run in. After all, the transfer box oil has to lubricate and cool quite a few new items at the moment. These overdrive units seem to be quite well thought of, and presumably fairly robust and reliable. I can't find anyone on the internet who claims to have broken one or says they had one which was faulty from the outset. Now if you compare this with Quaife transmission components, which used to be the Rolls Royce of limited slip diffs and gearbox internals, there's material all over the internet about how quality has gone down and they only last one race meeting. You can't take everything literally you read on the web of course, but as a barometer of public opinion I think it tells you something.

I have a very slight weep on the front output flange. The surface that the seal rubs against wasn't brilliant, but I thought it would do. Maybe not. It's not enough to drip on the ground, just to make the casing slightly moist. However, the drive flange and seal are straightforward enough to change on the car - re: Buster's guide - so it's not a problem. It's OK as it is but I'd like to get everything perfect. I might change them when I do the oil change after the running in period.

Been a good read this and if I still had the series I would have been tempted to fit an overdrive. The 110 has a five speed box though (not showing off really!) so one less thing to worry about!