Series III gearbox rebuild

[Snagger]

Right - question to those who abuse gearboxes - has the reverse gear shaft EVER broken on you? I'm wondering if I need to replace it. It looks ok - some longitudinal scratches but no ridges and no wear areas.

I've never heard of it happening - the shaft can wear badly on earlier models with bronze phosphor bushes instead of needle bearings (Suffix A cases, including Suffix E re-manufacture boxes using Suff A casings, like mine) if the unit is neglected, but that wear is very easily visible producing a step on one side and scoring. I have had no trouble with mine behind the Tdi.

I have seen reverse gears strip their teeth of crack across their diameter, but that would be due to fast spinning wheels in reverse off road suddenly finding grip and shock loading the transmission - in other words, stupid drivers who hit the throttle harder when they lose grip.

[lexi]

For the money..............if in doubt?

http://www.ebay.co.uk/itm/Land-Rover-series-3-reverse-gear-shaft-box-591527-/360307572110?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item53e4013d8e#ht_1329

[Gazzar]

I think I'll keep the shaft - there is no deep scoring - only surface marks. There are no wear lips, and I think it's fine! I'm replacing the cog - the pits on the teeth are enough for me to condemn it for this box - I might reuse it for one of my own projects, behind a less torquey engine.

G.

[Soren Frimodt]

This is a seriously good write-up! Keep it coming

[Gazzar]

Thank you. I hope to get started on the mainshaft tomorrow - no promises, though.

G.

[Gazzar]

Quick Question/thought: I want to record the parts/bearings that are needed to rebuild a box - no chat, no pics, just the part numbers, descriptions, dimensions, that sort of thing. I don't think a thread is the right format,I think that a blog may be more suitable?

What do you think?

[lexi]

I don't know.................just send me mine on a postcard

[Snagger]

Quick Question/thought: I want to record the parts/bearings that are needed to rebuild a box - no chat, no pics, just the part numbers, descriptions, dimensions, that sort of thing. I don't think a thread is the right format,I think that a blog may be more suitable?

What do you think?

I started my "nickslandrover" blog so that I could include as much detail and as many photos as possible without the distraction of discussions and topic deviations, but with the readers available to write comments and contribute their experiences, opinions or questions. Those comments each have to be vetted and approved before they "go live", mainly to prevent spam but also to avoid irrelevant deviations from the post. I do get a lot of spam, just like any site, but I haven't had to delete a single genuine comment - thankfully the site hasn't attracted any malicious comments, wind-ups or spurious conversation. The blog also allows direct emails so readers can contact me without their comments or questions being public, and this function is typically used four or five times a week.

I hope that a lot of people have found it useful - the amount we learn from each other in this community is huge, and while forums can answer most simple questions, detailed blogs can show a good deal about a complex issue and also allow the poster to show a wide range of projects. The trick is to set the blog up with an easy navigation system, not just to have page after page without an indexing method.

Blogs do take a lot of time to keep up to date, though, and of course you have the issue of the cost of hosting, but if you're willing to spend the time and money, I'd encourage you to follow that route; it's really great hearing from people all over the world and is a wonderful feeling to know you've helped someone with a problem or decision with their vehicles.

[Gazzar]

That's interesting! I was looking at your blog this morning - just seeing how much you replaced when you rebuilt your gearbox!

The maintenance of the blog would be an issue - I can be lazy, so that may be out.

I think I'll stick with the little book - every part has a page.

Anyway - I've stripped the mainshaft and it looks ok, I think I'll have to replace the 3rd gear, and possibly the input pinion, but the rest is ok.

Now, a tricky subject, non-genuine parts.

Some online part sellers sell the non genuine as "OEM" - would they be safe to buy? It's described as "Original Equipment in Plain Box". Would they be telling the truth?

Obviously I'd not be touching bluebox for important stuff, but is the greenbox better?

Pictures to follow, as soon as they've uploaded to the photo bucket.

G.

[Gazzar]

Mainshaft:

I decided to look at the mainshaft and the input pinion together - it kind of makes sense if you think of the position in the gearbox.

Here it is in all it's glory - Quite long, really!

Looking first at the input pinion it still had the bearing on it.

I recalled that this was quite loose from when I took it out of the bellhousing so a couple of gentle taps with a small hammer removed the bearing completely.

Close inspection time:

The land where the seal sits:

The splines where the clutch slides back and forth:

The gear where the constant gear on the layshaft is in constant mesh:

And the cone for the syncromesh:

And the inner gears:

And the bite gears for the syncromesh

My assessment is as follows, but I'm very open to correction!

The gears and cogs are fine - no wear, no pitting and the cone is supershiney.

The shaft itself is rusty, but recoverable with some molasses/wet and dry paper.

The land is no good - it would eat seals, however............................

I'm keen to try a speedisleeve - these clever bits of stainless steel simply shove up onto a wear surface and replace it - they are only molecules thick and so the standard seal will work.

They are made by SKF and so can't be that bad.

Any contrary opinions? Is this scrap?

[Gazzar]

Next I tackled the mainshaft 3rd and 4th syncromesh.

This was already loose:

Here are the pictures, I think it is fine - all I'm going to do is change the springs and ball bearings.

Anyone think otherwise? Is there anything I should also check?

[ejparrott]

I started my "nickslandrover" blog so that I could include as much detail and as many photos as possible

I hope that a lot of people have found it useful

I have!! :i-m_so_happy:

[Team Idris]

Cracking photo set

Spring change is a good idea as one broke on mine. I hate stripping half a truck for one iddy biddy part!

If your doing the transfer box, I believe I have a couple of photo's I can scan in and upload on making it 2WD-4WD independant of each other. By chucking the linkage and fitting the shaft with one of the gearbox selector balls/springs.

[Gazzar]

The 3rd and 4th gears need to be removed, as they sit on a bronze bush which is crucial for a good gear change - this bush wears/breaks and needs to be inspected.

It is held on the shaft with a split ring - like a circlip without the helpful little holes.

I find it easier to have the shaft held solidly while I work on it so I set it up in the mainbox casing, the wrong way around:

Here is the split ring - good fun to dislodge!

I used 3 thin flat blade screwdrivers to expand it out of the groove:

Quite Heath Robinson, but it worked. If anyone has a better plan, please let me know!

as you can see, a few taps on the 3rd gear allowed the split ring to slide down the shaft.

Fiddly flipping thing:

Once removed the 3rd gear, the 4th gear and the bush all slide off.

Asseesment time:

3rd gear:

The bush (single piece)

and 4th gear

Assessment, as far as I'm concerned, is that 3rd gear is scrap - the rust on the cone is too bad to be recovered. The bronze bush, too, is scrap, the scoring on the 3rd gear surface is too much. The bush should be replaced as a matter of course, anyway.

And finally the 4th gear is fine - no wear and no damage.

G.

[Gazzar]

Finally, the 1st and 2nd gear cluster.

This came apart easily, at first anyway.

This is the in-out gear, it kind of just exploded out when I turned the mainshaft on it's side, and I lost one of the bearings (which I would have replaced anyway).

And more:

Time to shift the bearing housing.

I held the housing on the bench edge and hammered at the shaft with the rubber mallet until it came out.

Mainshaft looks fine, no need to replace:

Syncros look fine too.

As does the In-out gear

Sorry about the duff shots - I wasn't using my regular camera, as it was being used as an internet radio (it's a cleverphone).

The bush looks fine, too!

as does the other syncro:

First looks pristine:

In fact I'm a bit suspicious as to the lack of wear on a lot of these parts! I suspect it was a replacement box fitted to a vehicle that was scrapped soon after. The shame is that it was left outside for such a while!

The final act in todays play is to get the output bearing out of the holder.

Bearing in holder:

Circlip removed:

Shiny outer of the bearing:

and evidence of the bearing turning in the holder.

I suspect that bearing seal may be on my purchase list!

That's all for this week, I suspect, as I have been threatened with spending time with the family over the next few days.

[discomikey]

ive got to replace the synchros on mine :/

[Gazzar]

Any chance you could post up pictures of them? I'd like to compare what's worn and what's okay.

[ejparrott]

That little clip that imitates a circlip is whats failed on my current gearbox...I keep finding bits of it stuck to the magnetic plugs....

Good news, AW Transmissions phoned me today, the replacement box is ready for collection, having had new 3/4 synchro, new 1/2 synchro, all new bearings bushes and synchros always, also new first and second gears!

[discomikey]

gazzar, i will do when i get home, they dont look particularly worn to be honest, but they do crunch a little especially into third. the only trouble being the syncro unit for 3rd and 4th is a bit on the steep side. i think ill try to rough up the cone a little for a bit more friction so it meshes better.

ive also noticed the pinch bolt on the 1/2nd selector fork-shaft is worn leaving play so that may be something to look at too.

im quite surprised though that theres little damage at all in there apart from a snapped spring/plate/thing in the 3rd/4th synchro unit which was probably not helping matters. especially as im running a rather tuned TDI which boosts 20psi at the turbo. and i do have my traffic lights grand prix moments + wheelspins in the wet and drifting. its all in pretty good nick, replacing all of my bearings and couple of synchros, putting it all back together with new selector pinch bolts and maybe machining a new (bigger) ball for the gearstick into the selector cups so it doesent have any play when in gear.

im not touching my transfer box as it seems good and they never seem to break

[lexi]

but they do crunch a little especially into third. the only trouble being the syncro unit for 3rd and 4th is a bit on the steep side. i think ill try to rough up the cone a little for a bit more friction so it meshes better

.

If it don't come out perfect you can easily double de-clutch. Mind you.......probably not the point of all synchro box.

Good stuff Gaz..

[Snagger]

All of those parts except the 3rd gear and bush you have already condemned look good. I'd replace the leaf springs in the 3rd/4th synchro unit and take a close look at the coil springs in the 1st/2nd synchro, but they all just hold the synchro hub in its neutral position - the hubs are held in their engaged positions by the selector detents (those springs are worth replacing, and remember that of the three detent springs, the harder one is for the left hand reverse shaft, not for the central 1st/2nd shaft).

The scoring inside the rear bearing carrier may be from the bearing spinning, but might also be from coarse machining. As a non-bearing surface, it doesn't need to be polished, and may have been left rough like much of the main shaft. But, you must use bearing seating compound for fitting the carrier to the main casing in order to prevent that from spinning (the ali case expands more than the steel carrier as it warms up, allowing it to spin and the circlip then cuts the face of the casing, producing swarf; this is also where the oil migration from gear box to transfer box occurs), so you can err on the safe side and seal the bearing in securely.

I'm sure I don't need to say it, but warm the carrier in the oven for 10 minutes at 100oC and put the new bearing in the freezer (in its packaging) for a few hours before fitting to allow easier fitting, adding the compound to the outer race before insertion, and drift the bearing in by tapping its outer race only, not pressing or tapping the inner race.

You can later freeze the complete carrier assembly inside a food bag to contract it, and warm the casing gradually and evenly with a gas torch to expand it before fitting the carrier. Just make sure any frost is removed from the carrier before adding the bearing seating compound.

[Snagger]

By the way, the photos show you have a Suffix D or later box - the 3rd/4th synchro hub teeth are coffin shaped rather than having parallel sides and the 3rd and 4th gear inner teeth have recessed flats (some people mistake these for wear) which help keep the gears engaged on torque reversals. These are what is meant by "ECM" (electro-chemically machined) gears, though ECM is just the manufacturing process, not the profile description.

[Gazzar]

Thanks for that Nick!

I had spotted the recessed flats on the input pinion, but hadn't realised the significance, but I'd not spotted the coffins!

For those, like me, who don't know what to look for here is a close up:

Very coffin shaped, indeed!

That would mean it's one of the stronger series boxes, wouldn't it?

I must say I have been surprised at the amount of effort that has gone into ensuring adequate lubrication throughout the box, with channels and cuts in place to get oil to where it is necessary.

No more work done on this, and probably not until Monday or Tuesday, as the ignition on the 109 has decided to play silly buggers, not sure whether it's the switch or the barrel, so I'll have to strip the lot down.

G.

[Snagger]

Yep - it's the strongest type of box. Mine is a factory rebuild Suffix E, rebuilt from a Suffix A case, so it has the later improved version of the Suffix A reverse idler gear with the plain bush (I don't know what the improvement was, but the Suff A cases can't take the later needle-bearing idler gears and shafts because of the dimensions of the supporting web and the shaft holes). The rest of the box is the same as a late production Suff D unit.

The Santana boxes are reputed to be tougher still, but they just have Suff D innards. Their only difference with a LR Suff D box is the casing, which has reinforcing webs all over much like an LT77, but I've never heard of someone cracking a case while fitted (only by dropping a case on the floor).

[lexi]

To think that I threw in a Gen Rover low miles recon suffix D with the sale of my last SW as a spare . I must have thought I was Santa Clause

Any one tried a rubber backed bearing as well as the bearing seal, to stop migration? Timken do a version I'm sure.

Does the migration only take place at certain times of year or is it all round......