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Series III gearbox rebuild


Gazzar

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Right, after simply ages I've finally started in on this box.

I decided to commence with the main box, and I have to say that the ROM Green Bible is brilliant, but absolutely hopeless.

It's all over the place. Bits here, bits there, bits everywhere - mind you it may be that I have the pages in the wrong order!

I am starting with a couple of rebuild kits and a variety of new gears/shafts, as the old ones were corroded/damaged. I got this box of bits from a dealer/repairer on the Irish forum, guy by the name of Dan Dikson in the West of Ireland.

So, to commence, the reverse gear.

The reverse gear in the box was rubbish - rust from when the box was neglected, and so new shaft and gear to fit.

Warning - this is picture intensive, so if you are on dial-up this may take a while.

To refresh, the stripped main box:

2012-10-16-1034.jpg

2012-10-16-1035.jpg

2012-10-16-1036.jpg

2012-10-16-1037.jpg

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Where was I?

Oh, yes! Reverse gear.

New bit!

2012-10-16-1039.jpg

2012-10-16-1040.jpg

And the old spacer plus bronze washer:

2012-10-16-1041.jpg

The gear comes with the bearing built in.

2012-10-16-1042.jpg

Parts manual and ROM

2012-10-16-1043.jpg

2012-10-16-1044.jpg

Assembly order: Well, I think so.

2012-10-16-1045.jpg

2012-10-16-1047.jpg

Opps, I think IE has died again, maybe I need to reboot the old laptop. Let me see, does Chrome support photobucket?

Oh, yes it does!

Hold the gears and spacers/washers in order on the finger and start the shaft in from the back of the box:

2012-10-16-1049.jpg

2012-10-16-1050.jpg

The shaft will be proud of the box, gently persuade it into the box until it is flush.

2012-10-16-1051.jpg

2012-10-16-1054.jpg

2012-10-16-1055.jpg

I think I warmed up the casing with the propane prior to fitting the shaft, so a few taps with the plastic hammer served to seat the shaft home.

One thing - make sure the hole for the spring pin is aligned with the recess on the outside of the back of the casing.

2012-10-16-1052.jpg

I don't have a pin, so I'll put that on the extra parts list I need to order.

Next up - start the main shaft!

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I knew I wouldn't get all the way with this one, as I'd lost the 1/2 syncro springs and blocks (stupid, but I had to clear out the garage to get the lathe in).

Lets see how far I can get, shall we?

Naked mainshaft:

2012-10-16-1057.jpg

A heap of bits, some of which may belong to this gearbox:

2012-10-16-1058.jpg

This bit is the outside of the 1/2 syncromesh, and is also the reverse gear, I think.

2012-10-16-1059.jpg

If you look deep inside you will see the little cut out grooves for the ball bearings on the syncromesh.

This is the inner bit, that stays in place on the mainshaft:

2012-10-16-1060.jpg

Note that the groove around the middle isn't exactly central - this is important.

This is the way they go together:

2012-10-16-1061.jpg

I think.

Slide one into the other, checking that the missing splines are central with the cut-outs grooves on the outer bit.

2012-10-16-1062.jpg

2012-10-16-1063.jpg

The manual says to check the fit in all three possible combinations, one was ever so slightly freer so I went with that one.

Now, I was missing the blocks and springs so that's all I should have done with that, but I decided to keep going - knowing I'd have to rip it back later, but it would allow me to get the tolerances right later on.

So, next up, the second gear/third gear bronze bush set up.

G.

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The Second gear, with it's cone:

2012-10-16-1067.jpg

Bronze top hat section bush and 2nd hear on the shaft:

2012-10-16-1070.jpg

And tolerance being checked:

2012-10-16-1068.jpg

It's got to be 0.007 to 0.004 of an inch. if I recall correctly.

Push down the bush hard and then see if the clearance is right And so, if the 0.008 feeler gauge fits in then the bronze bush is too long.

Make sure the key way and the key on the shaft are aligned:

2012-10-16-1072.jpg

2012-10-16-1073.jpg

This one was 0.006, so was fine.

2012-10-16-1068.jpg

Next, do the same job for the 3rd gear.

Slide on the next bronze bush, and third gear,

2012-10-16-1074.jpg

2012-10-16-1075.jpg

then the thrust washer:

2012-10-16-1077.jpg

2012-10-16-1078.jpg

and while holding the shaft in one hand, push down on the thrust washer to tighten the cluster together, then take the feeler gauge and measure the gap.

What?

Don't have three hands? You'd want to see a doctor about that mate!

Anyway here's how I did it.

Take a piece of 1 1/2 inch waste pipe and trap it in the vice:

2012-10-16-1079.jpg

2012-10-16-1081.jpg

And drop the shaft into the pipe:

2012-10-16-1083.jpg

This will mean that the weight of the whole thing will keep the thrustwasher/bush/tophat bush/thrustwasher assembly will be tight, allowing me to check the gap.

2012-10-16-1085.jpg

This one was fine.

Disassemble the various gears and bushes and reassemble without the gears:

2012-10-16-1087.jpg

Note that the spring snap ring is also on - USE THE OLD ONE, after checking that it is the same thickness as the new one.

I hate these little snap rings.

Nothing personal, just hate them.

Check the tolerance:

2012-10-16-1088.jpg

This one was fine, all good so far - no sandpaper required, no parts too short.

Good!

How DO you get those flippin' rings off?

This is how I do it:

Small screwdriver under one end and lever:

2012-10-17-1089.jpg

2012-10-17-1090.jpg

And twist another screwdriver into the new gap until it's out of the groove all the way around. It works.

Still hate them.

2012-10-17-1091.jpg

Guess which is the old ring? Use the new one.

Ok, time to lube up! I like to put a skim of grease on these things, just in case the oil isn't fully right on day one.

2012-10-17-1092.jpg

2012-10-17-1093.jpg

And pop the 2nd gear on the shaft - checking the bush alignment, of course.

2012-10-17-1094.jpg

2012-10-17-1095.jpg

And then 3rd gear!

Bush, non-top hat version:

2012-10-17-1096.jpg

Gear, hopefully right way around:

2012-10-17-1097.jpg

Correct thrust washer.

2012-10-17-1098.jpg

All the way home!

2012-10-17-1099.jpg

Spring snap ring, did I mention I dislike these?

2012-10-17-1100.jpg

On all the way around:

2012-10-17-1101.jpg

And sliding down the shaft:

2012-10-17-1102.jpg

Right, going to take a break - more later.

G.

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I knew I wouldn't get all the way with this one, as I'd lost the 1/2 syncro springs and blocks (stupid, but I had to clear out the garage to get the lathe in).

Lets see how far I can get, shall we?

Naked mainshaft:

2012-10-16-1057.jpg

A heap of bits, some of which may belong to this gearbox:

2012-10-16-1058.jpg

This bit is the outside of the 1/2 syncromesh, and is also the reverse gear, I think.

2012-10-16-1059.jpg

If you look deep inside you will see the little cut out grooves for the ball bearings on the syncromesh.

This is the inner bit, that stays in place on the mainshaft:

2012-10-16-1060.jpg

Note that the groove around the middle isn't exactly central - this is important.

This is the way they go together:

2012-10-16-1061.jpg

I think.

Slide one into the other, checking that the missing splines are central with the cut-outs grooves on the outer bit.

2012-10-16-1062.jpg

2012-10-16-1063.jpg

The manual says to check the fit in all three possible combinations, one was ever so slightly freer so I went with that one.

Now, I was missing the blocks and springs so that's all I should have done with that, but I decided to keep going - knowing I'd have to rip it back later, but it would allow me to get the tolerances right later on.

So, next up, the second gear/third gear bronze bush set up.

G.

That is the wrong syncro for your suffix D gears as its for suffix B & C only. The internal teeth in the outer ring are plain, for the D they should be like the internal teeth in the 3rd gear with a lip on the sides of the teeth.

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Okay, looking at the parts manual I see that RTC2195 is for the B & C boxes, whereas RTC2685 is for the D box.

So you are saying that this is not an RTC2685, right? Damn, I'm going to have to get one of those.

Ah well, nevermind! I'll stick it on the list.

Thanks!

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Right, I've asked the guy who supplied the parts, Dan Dikson, about this and he's kindly sent me a few pictures of the different versions of the "IN OUT" gear. I think he's dug out the different gears from his stock just to show me, which was very decent of him.

I've attached a couple of his pictures -

The first shows the different gears: Left to right A/B/D.

The key difference is that the D gear has 30 outer teeth and the others have 31.

Assuming I can still count after a day at work, that is!

And the gear I've been using has 30 teeth.

So, now I'm thinking I DO have a suffix D box In Out cluster?

The second picture is of the inside of a D cluster inner, according to Dan.

Confused, formerly known as Gazzar.

post-3246-0-74780700-1350582077_thumb.jpg

post-3246-0-26138000-1350582890_thumb.jpg

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Right, more evidence to support my theory that I've the right gear:

The suffix D inner outer gear HAS 30 teeth:

http://www.shop4autoparts.net/Series/Gearbox/LT76/Gears/rtc2685-HUB-_SLEEVE-ASSY-SER3-SUFD-30T.html

The A suffix has 31 teeth

http://www.shop4autoparts.net/Series/Gearbox/LT76/Gears/608283-inner-&-outer-assembly-31t.html

and the B/C Suffix has

30 in this picture:

http://www.ebay.co.uk/itm/NEW-LAND-ROVER-SYNCHRO-HUB-1ST-2ND-SERIES-3-SUFFIX-B-C-RTC2195-/160856705715

I note some websites show the B/C as being compatible with the A box, but some don't.

So, does anyone else know for sure - how many outer teeth has the B/C version, part number RTC2195?

G.

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The photo shows 2 x A members (left and middle) and what looks like 1 x D member. If you look at the visible inner teeth at approx 4 oclock the steps in the inner teeth is visible.

B, C & D all have the same number of outer teeth and they all use the same reverse idler.

A, B & C all have straight inner teeth.

D has stepped inner teeth.

B, C & D all have the scribed ring on the end face.

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  • 3 weeks later...
  • 9 months later...
Thank you. I hope to get started on the mainshaft tomorrow - no promises, though.

G.

I have to say how much this is helping me , I really would not have tryed to do my box without this thread ,thanks so much for all your time doing it .

I am half way now about to take out main shaft .

Thanks millions stJohn..............

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  • 7 months later...

Hi guys this is a great write up, I'm just about to have a go at mine.

I have a series 3 box in a 109 'parts vehicle' and what I think is a series 2 box as a spare in the shed but I'm not sure. Its numbered 90124215A on the selector housing. So its a 2 right?

Is the transfer box interchangeable between series 2 and 3? I am thinking about rebuilding the transfer box that's out of the car as a project prior to removing the Series 3 box from the donor 109.

Also the reason for rebuilding a box is the one that's in my "on the road" 109 makes a huge clunking noise when I put it in reverse and move back and when you put it a forward gear and move forward. No problems on the road really if your gentle with the clutch release. Would anyone know what's causing that?

Its a backlash of some sort but I have removed the front prop and replaced the UJ and yoke on the tail shaft and all the drive flanges so it has to be in the box somewhere? The diff seems tight enough.

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interesting, I just put it into low range then tried reversing then taking off in each and it didn't seem to do it in 4th...

I will have to try it in high when the driveway is clear, its like a parking lot at the moment, but it seems like not in 4th at this stage?

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Hi Shambo.

Backlash is always worst when going from forward to reverse, or vice versa, and even a brand new transmission has some.

It's backlash, probably from worn splines. I'd look at the splines on the rear end of the main shaft and inside the gear that that sits on it, and if it never occurs in 4th, then I'd also be looking closely at the condition of the splines of the front end of the lay shaft and the gear engaged on them. If you have a SII box of any type, the whole lay shaft is splined, so all of the gears on there cold be loose. SIII boxes have a better lay shaft where all the gears except the big front one (drive from the pinion) are integrated, so the only backlash on them is from that front splined joint (unless the gear teeth are extraordinarily worn).

All Suffix C SII transfer boxes and later are identical (save for the 1-Ton) and even the early SII types are interchangeable with the SIII.

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Thanks for the info Snagger.

I intend remove the overdrive and put this lot into the series 3 box (in the daily driver with the back lash issue) as the overdrive screams in high and needs sorting when I get time anyway.

IMG_0873_zps935fe3b7.jpg

It's out of the box I think is the series 2 and I think it should fit. I am waiting for a lock washer to fit it and am hopeful that may also be part of the backlash issue.

The noise is like a metallic shudder with an echo. Its really quite loud. I cant say I have ever heard one as bad as it and I have had a few series landies.

Sometimes when its moving in reverse on a small hill roll back with the clutch in you occasionally get the same type of noise. That maybe unrelated to the box issue itself and in the hand brake, something I will be looking as well if I cant track it to a loose nut when I remove the overdrive.

I'm not sure how the overdrive fits on the shaft, its a fairey unit. I know the unit pulls away, what's left on the shaft I'm hoping it is loose and is causing at least some of the backlash noise on the shaft.

If all else fails the boxes to play with are as follows:

Pic 1 - I think Series 3 suffix A (with a 6 cylinder bell) - its in the daily driver and has the back lash issues. Full number is 90223526A. Its obscured by the overdrive rod.

IMG_0870_zps9cfcdbd3.jpg

Pic 2 - I think Series 3 Suffix A (with a 6 cylinder bell) - its in the donor. I believe needs a rebuild, drops out of gears I was told. I have never driven it further than onto the trailer as it had a bad clutch master. May just need balls and springs in the selectors. That vehicle is still a runner except for the clutch not working properly so I don't really want to fiddle with it if I can help it.

And yes there is a gearbox under all that dirt :lol:

IMG_0868_zps49565ff0.jpg

Pic 3 - This one is in the shed, I think its a Series 2 or 2a? Has a 4 cylinder bell

d4a634da-470a-4c5d-8460-0d5e3044d946_zps

Pic 4 - This is a box of mystery gears, gear box and transfer case pieces I picked up somewhere. Not sure what's there. There are doubles of some things. They need a good soak to remove the surface rust then sorting for useability. Maybe the shaft/gear I need is in there.... fingers crossed.

Any ideas series 2 or 3 stuff or both? they may all be scrap depending on how they clean up.

IMG_0866_zps40b27ab7.jpg

photo_zpsbd162ccf.jpg

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Like mentioned above it sounds like a layshaft issue and the reason i asked is because 4th gear is a 1:1 direct drive where the input shaft is locked to the output shaft, the layshaft just spins redundantly when in 4th. this isolates any problems that may be within the layshaft or its bearings, does it sound to grind either under power or on overrun?

identifying those shafts and gears could be tricky i think it would have to be a case of counting the teeth and comparing to your current gearbox, or asking someone on here which tooth counts belong to which type. the earlier type boxes (like your S2A box if it is that one???) have the multi piece layshafts that you see in the bottom photo second shaft from the left on the bottom row.

the single piece one is the one next to it you need to find the mainshaft gears to match either one of those shafts, to find a paired up set.

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That's quite an assortment of SII and SIII gear box parts and transfer box parts. The left hand shaft with four integrated gears is a SIII lay shaft. Next to it is a SII lay shaft, then a transfer box main shaft The two bare shafts are gear box main shafts, but I can't tell if there is a difference between SII and SIII - they look the same to me from the photo. The last shaft is a SIII main shaft with 2nd and 3rd gears still fitted. Top left is the front output shaft for a transfer box and top right is the primary pinion or input shaft for a gear box. The two tall double-gears in the bottom right are transfer box intermediate clusters, whose shaft and two bearings are in the top centre of the photo. The small gear at the very top is a reverse idler gear, quite early by the look of it. To its left, the bonze bush with internal splines if for 1st gear on the main shaft.

On the bottom of the left side of the picture, you have a gear for the back end of the gear box main shaft (where the overdrive coupling would be). Furthest left is a lay shaft input gear, which meshes with the primary pinion. Above the lay shafts is a SIII 1st/2nd synchro unit and on the right two 3rd/4th synchros (with the brass ring cages). Which Suuix some of these parts are will dictate their compatibility with the two transmissions you have and each other.

Fairey type overdrives howl when engaged and there is nothing you can do to stop it. It is not necessarily indicative of a problem, but if backlash increases with the overdrive selected to one position or another, there may be a fault. I have a rebuild guide in the FAQ section of my blog. As for the transmission noise taking up drive, would you describe it as a solid clunk, click, clack or squeal? A deep clunk is likely to be diff backlash or play in the engine and transmission mountings, a clack is transmission backlash, especially likely on the overdrive input, and a click is likely to be prop shaft UJs. Squealing when driving is usually UJs, especially if vibration is present and worst at multiples of 30mph.

As suggested, chock the wheels very securely and select the transmission to neutral (including the transfer box) and check for play in the prop shaft UJs, splines joints and the diff and transfer box flange bearings. Then look for loose nuts or damage rubbers on the engine and transmission mounts. Also check the hand brake shoes aren't dragging - they make clunking noises, though they tend to do it continuously at low speed, not just on taking up drive.

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