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Series III gearbox rebuild


Gazzar

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Oh, and I've heard that some Genuine LR seals are now poor quality, so it's back to the old maxim - pay your money and take your chance.

I'd love to be rich enough to buy one of each part and get them professionally assessed, something which the Magazines should do, but of course that could upset the advertisers!

G.

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Layshaft = junk, no question.

Reverse = hmmm, change it as they are not that expensive. (kit I think includes shaft and bearing/bush)

Julian

Thanks,

That's what I was thinking.

G.

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I got a Bearmarch branded layshaft for mine from Landranger services. It's early days yet but so far so good....

If you need a snap ring for 1st 2nd bush (I think) I'll mail you one as I had to get a bag of five genuine LR ones from a dealer, the one Landranger sold me didn't have enough 'spring' and bent upon installation.

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Oh, learned that one on a series 1 box I did a few years ago!

I appreciate the offer but I'll be putting together a big order, if we go ahead!

G.

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I agree that the lay shaft and reverse idler are fit only for smelting. The rest looks fine, though the 1st and 2nd synchro rings can't be assessed from the photos because they don't show the fine ridges. If the ridges are intact, like on the 3rd/4th synchro, then they're good to go. I also echo the advice about the detent springs - replace them all.

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Sorry for the delay on this; I don't know where the time goes, and don't have time to find out, either.

The plan is to assess this box and see if it's economical to rebuild, if so, to do the work for mid August.

So,

Some pictures of the bits I plan to junk, and why. Opinions requested, as it would reduce the cost to re-use these parts. The cost of parts is now at £600+ VAT.

Oh, and this box will go behind a V8, so it's got to be good.

First up - the layshaft.

This is all good except for the very last cog, which has a tooth badly corroded. Just one tooth is really bad but the rest aren't too hot.

2012-07-31-687.jpg

Verdict, junk, possibly kept for a hackabout gearbox. Or as a dumbell when I get around to getting fit again. Laugh.

3rd 4th syncro thing:

2012-07-31-682.jpg

2012-07-31-681.jpg

The little coffin shaped teeth are damaged on the very tip - between the top of the coffin and the front two faces.

Result - junk. I think. Again, could be ok in a hackabout, but not in a good box.

The In-out 1/2 gear

2012-07-31-683.jpg

Same issue - I think that these are key to a clear / clean gear change so it isn't good enough.

Second gear

2012-07-31-684.jpg

DItto

Reverse, just worn out, I think.

2012-07-31-685.jpg

ANd 1st

2012-07-31-686.jpg

Chipped coffins. So probably not good enough for a 1st rate box.

Syncro rings. These are probably fine, but as I'm changing everything else around them I might as well do them too.

2012-07-31-688.jpg

Or is the quality of these little parts irrelevant?

G.

The 1st/2nd syncro shown stripped to expose the inner teeth is for a suffix B or C not a D as the coffin shape teeth are unique to D or later.

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The 1st/2nd syncro shown stripped to expose the inner teeth is for a suffix B or C not a D as the coffin shape teeth are unique to D or later.

Good spot - a D suffic synchro would have notched inner teeth much like inside the input pinion and 3rd gear.
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Good spot - a D suffic synchro would have notched inner teeth much like inside the input pinion and 3rd gear.

Yes, but thinking aloud here: If the entire cluster is the same suffix then does it matter? in other words, all the bits that interact are the same, so it shouldn't effect things.

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I think you're saying that as long as the 1st and 2nd gears and their synchro unit are A-C and the 3rd/4th synchro, the 3rd gear and the input pinion are all D, then all is well. It's not quite as simple as that - the lay shaft also varies betweem A-C and the D and later suffixes. Apart from a small step behind the first gear, I don't know what the lay shaft differences are. As far as main shaft oiperation is concerned, I can't see any problem mixing and matching (as long as the clusters are matched), but Phil may know mor about the lay shaft and its gear profiles than I do.

Take a look inside the pinion and third gear and check that they have the stepped D suffix teeth - they should have recessed flats on the sides of each tooth about 1/4-1/2mm below the main thickness to allow the coffin shaped teeth to engage in a way that resists popping out of gear with torque loads applied. If the teeth are flat sided, you just need to replace the synchro with an A-C one.

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All the 3rd 4th stuff is going to be replaced - it's junk. Rust killed the pinion and the gears.

I'd forgotten that the layshaft was different.

Anyway - I think that the owner may be going down the R380 route. When you add up all the costs there's very little in it, and, as he already has a decent R380, it makes a bit more sense to use it behind the V8.

So I might rebuild this box with the cheapest parts I can find, just to see how bad they really are. Blue Boxes everywhere!

What's the law on poor quality parts in England? Can I return them after examining them if they really are rubbish?

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As I understand it, if they are of very poor quality, then they are unfit for purpose and you are entitled to a refund, but nothing more. Britpart bearings and seals are utter carp. Good quality bearings don't cost much more if you buy them from a bearing specialist - it's buying them through garages and car suppliers that is expensive.

If going R380, you'll need to use the short nosed version, which is pretty uncommon and commands a correspondingly high price. The standard long version might not fit without moving the transfer box aft and the engine well forward, with a lot of chassis, hand brake linkage and prop shaft alteration.

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What's the law on poor quality parts in England? Can I return them after examining them if they really are rubbish?

It's proving that they're rubbish without costly equipment or specialist testing. Take the cheap non-branded Chinese bearings that Britpart sell, and I don't mean the perfectly good branded budget bearings that the likes of simplybearings sell; you've seen (I'm sure) Quest on Freeview and making ball bearings? It's obvious how you could make them cheaply, just omit half of the manufacturing processes like proper case hardening, proper selective fits of races, proper grading of ball sizes, lower grade steels etc. Result is a poor product with the balls all of slightly differing sizes and fighting each other from the word go, and a lot of wear resulting in a short lifespan.

Britpart gears must be another example, again choice of material, poor (involute) tooth profile, substandard case hardening, poor dimensional control etc. But pull it out of its blue box and it will look perfectly good.

It might be an interesting exercise but for my money I'd find something more productive as I think we already know what the verdict will be!

Julian

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Some of these cheaper parts are like a toy replica gun versus the real thing.........yet some other cheap parts work surprisingly well.

Getting good Chinese parts is an art in itself.,,,,,,,like finding out who made them and how.

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Yes, I know, still, I'd love to have the kit and brains to challenge them!

I'm disruptive that way!

Anyway - we're still debating the way to go with this box.

What do I have to photo to confirm whether the 1nd and 2nd gears are ECM or plain cut? I can see a slight taper on the nubs, does anyone have a picture to show the difference?

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Some pictures (gotta love camera phones - so convenient).

2012-08-02-701.jpg

2012-08-02-702.jpg

2012-08-02-703.jpg

2012-08-02-704.jpg

Opinions? Worn out? D suffix or earlier?

Because if they are earlier I'll price up the corresponding layshaft and pinion - that might impact on the cost of the rebuild.

G.

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They are a little chipped, but it looks to me like they still have plenty of life in them. The chipping occurs during gear changes, and ironically, slightly worn teeth like that make changes smoother and easier as the baulk ring has more time to synchronise rpm before the teeth intermesh. I suspect that some of that damage has occured due to poor changes (rushed or the clutch not fully disengaged) and poor oil servicing (level and frequency of replacement, leading to contaminated oil carrying swarf through the teeth. I'd re-use the gears, but I'd take a close, hard look at the baulk rings, as they would cause this damage if they're worn.

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Baulk rings actually look very good, happy with them. Anyway we've taken a good chunk out of the cost - it's closer to £500 now, and that's changing a hell of a lot of stuff.

I've also ordered the speedisleeves for the output flanges - £20 a pop! Cheaper than the recon flanges, and a far superior finish.

G.

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