Looking for a Series 3 gearbox, LT76, preferably a later one

[vlad_d]

Okay, I'm trying something out.

Folks here have been telling me I need to put the feelers out to find a good deal. So, here goes...

My next project is a gearbox. I've got no one local who can do it...they all send it out, anyway. So, I'm in the market for a Series 3 gearbox. I want a standard LT76, preferably a later (suffix "D"?) as I've been reading these are more robust. But honestly, I just want "of equal or better quality" as I've got. I don't need a tank gearbox...and I'm not cutting up and re-welding to shoehorn in a later gearbox. Just stock part swapping.

It needs to be 100% rebuilt, and under the $3700 our hosts are asking. I don't need a lifetime warranty. But I'm not spending $2k-$4k and a month later I get weird noises or grinding. It needs to be professionally built, with proper endplay, etc. No backyard mechanic. I want it from a reputable shop.

Any leads would be much appreciated.

[jimrr]

it's been 13 days for you and no responses so I thought I'd tell you I know where a bunch of landrover parts are buried in a canyon just across the border in Idaho. The young person who owned all this was killed in a rock climbing accident when he was about 20 years old and the distressed family buried a lot of his stuff. parts, pto, xmissions etc. , one day I hope to pursue this story.

[vlad_d]

Thanks @JimR. I'm not quite ready to go digging up buried treasure ;P

Wow, been doing some reconnaissance. John Craddock was asking about 1800GBP(about $2300), which sounded like a good deal. But I emailed them and they had a supplier that no longer does it. So they can't sell me one. Their website still has the item, but they're not filling orders.

Our hosts send out to a supplier in the UK. There is a waiting list about 6 people long, and the lead time is about 4 months.

A local LR 4x4 shop is willing to do it for $180 hour...but it's like indefinite time. That's going to add up, quick.

So, I looked on ebay and found a local guy selling a gearbox case (suffix A, turns out mine is a suffix A, too)for $70 in good condition. All the bits are still available for sale. So, I guess I'm going to build a new one myself. I'm picking the gearbox case (suffix A) tomorrow.

My plan is to take my time and build it on the bench, in no hurry. My current gearbox still works, and is drivable. I'm hoping to build out the new one, and then just spend a weekend doing the swap...to minimize down time. Thing I was affraid of was pulling the old gearbox and laying up the Series in the front yard indefinitely. Maybe I'll take some pics along the way and post here. I can't tell if people enjoy that or hate it. But maybe it helps someone landing on this thread in the future. Wish me luck!

[jimrr]

i have been thru mine two or 3 times. syncros never seem to last!! I guess there are land rover bone yards far off the beaten path in africa with valuable parts and options there. no doubt salvaged a lot but ............. one would have to go there and spend a few months filling shipping containers !!

[vlad_d]

Seems alot of the parts are still available, with some exception. The main casing being one of them. Since I'm building one from scratch, I'll use this post to keep updated about parts availability and the build(not really a rebuild anymore).

Week#1:
I picked up the casing from about 1.5 hours away. It's an "A" suffix gearbox casing. It was a bit grimy, so I used a wire brush and then SimpleGreen and hot water to clean it up. Pics attached. It came out pretty clean. I don't have a parts washer, so I'll probably do this for the other old parts.


Gearbox Suffixes:
So, I'll need to buy or source parts for this new gearbox. They made changes over the years...so getting the right parts will be key. I'm learning as I go, so I thought I'd share the process. Maybe you know this stuff, maybe not...maybe it's fun just to go through it with me. Turns out, there are 4 "Suffixes" letters stamped on the outside of the box to identify it: A, B, C, D. The LT76 stands for "Leyland Transmission" and 76 is the distance between the two geared shafts (on center). So, right off the bat...lots of interchange possible. I think the tricky bit is identifying your innards, because some Searies 2,2a boxes didn't have synchros on 1st + 2nd and later suffixes used different gears plated specially that can't be used with earlier parts. But I'm sourcing all new parts, so I'll try to pick the right ones.

Finding the serial number and Suffix:
There are lots of numbers and letters stamped on the gearbox. But the ones you're looking for are on the top, back-right...on the removable housing that holds the shifter shafts. This is not to be confused with the big "A" on the right side, next to the Leyland logo. Also, the whole assembly of 1)gearbox, 2)transfer case and 3)output are three parts with their own serial numbers. You want just the gearbox. See pics.The Suffix is the letter just above the serial number. Luckily, you can just see it with the center seat/cubby panel removed.

Decoding the Serial number and Suffix
I scanned in a page from James Taylor's book, about gearboxes. This is a great resource for numbers and specs.See pics.

The "new" gearbox housing I have is a basic Suffix "A". Great!

As a fun fact, I looked up the one in the truck. Turns out it's a Suffix "B" and the 951 serial number shows it came out of a Military/Lightweight Land Rover. Hmm. Two things about that:

1) There are other signs my frame and differential are off an Ex-MOD Landy. The Salsbury rear diff has white "convoy" paint on the back cover. And the bumpers have J.A.T.E. shackle mounts on them. The gearbox is another nail in the coffin. I think someone replaced the rolling chassis on my S3. Also, the front-right spring hanger (the one with the VIN) was swapped...likey to register it under the same VIN.Hmm. Well, I'm all legally registered and papered, so I won't worry about it. But fun car history. I'm sure each Landy has a story or two.

2) The second result of this is that I might not have been ordering the right parts if I just assumed it was original. I have the parts book, and using part numbers from there. I might have assumed 1973, when that gearbox came out in 1977. So, I guess the moral is, check serial numbers, because previous owners swap stuff all the time.

It turns out the Suffix "A" box is more accurate for my year. But I had a mini mental crisis about what to do with the existing Suffix "B" in my car? It's actually the better gearbox. Looking into it, I guess the only difference is a stronger Reverse. I guess they improved the design on the Suffix "B" to better engage reverse. Since most people have their hand on the stick as they reverse, I'm not worried about it popping out. Let me know if any of you guys experience this with a working Suffix "A" LT76.

So, I'll finish the Suffix A build and swap them...maybe rebuild the Suffix B later and keep it or sell it. A used gearbox seems to be worth $100 core, and $3600 rebuilt. So, I'll not let it go without a profit. The math is just weird.

So, I ordered the first bit of parts - for the exterior. Bell Housing, front cover, seals and bolts. All of which are still available new. Part numbers and links in this spreadsheet:

https://docs.google.com/spreadsheets/d/13FmnoIo10uMIkS4IwnY6APv2wqMbJN3mUgVcGm0W1q8/edit?usp=drivesdk

[roverp480]

Looks to be an interesting project. I am not sure if I a reading your spreadsheet correctly, but are you planning to use a 2A bell housing, as it isn't suitable for the S3 clutch release mechanism. the two are significantly different ? S2A suffix B onwards is 556044 and S3 is 576714

[vlad_d]

Advice and ideas like this are great. Keep them coming. I'd love to find out stuff sooner rather than later. Thanks @Rover480.

So, since last week I got the Bell Housing in the mail. I ordered one off ebay because it was about $130 cheaper than the new one(plus shipping was cheap, only shipping from SoCal). It arrived and I used some paint thinner and a wire brush to clean it up, again. Then dry fit to the gearbox to confirm. To be honest, it was a gamble, because it didn't have a Land Rover part number. I had to use photos of it and guess. But I lucked out and it fits great.

I have the S3 Parts Manual, and here's the page from the gearbox section.(See attached) . Looks like you are correct, the one for the S3 is 576714. I also attached a pic of the bell Housing for comparison. It looks identical, except for an access hole on the left side of this view. Bolt holes seem to line up with the gearbox case. I haven't received the front cover yet. I'm hoping that matches, and I think it will because they will be part # matched for S3.

To be honest, I don't really know if the gearbox case is from a 2a. I have the part number and Suffix. That tells me it's an LT76 suffix "A", but not what it came out of. The guy I bought it off had a nice Dormobile 2a out front and he said the gearbox came from a 2a. But, you know, he could have had the same thought going on as me and my S3: some prior owner swapping out parts. So, I can't confirm if it came from a 2a. Anyone else can from the serial number?

Luckily, it seems to bolt all together. So the build is still on(whew!).

[vlad_d]

I had a though that I can't quite shake. Maybe someone on the forum can answer this one:

Seems the gearbox Suffixes tell you about the innards. I imagine no one is getting out detailed blueprints to identify the reverse mechanism from a Suffix A from the one in Suffix B. Or, no one is trying to mix and match plated gears from a Siffix D with non-plated Suffix A/B/C. So, the Suffix tells you what's inside....but the spacing of the bearing journals on the case is the same? So, to my thinking, if you wanted to put 100% Suffix D parts into a Suffix A case...it would work? Can anyone confirm this thought experiment?

I mean, it would screw over the next guy trying to identify the parts. But, if I'm buying 100% new parts in there...why not benefit from the latest design fixes over the years and get a stronger overall gearbox? Would that be unethical? I could put a metal tag on the gearbox with notes or something. As opposed to just putting in the inferior reverse gear just because it matches the "A" stamp on the outside of the case?

What do you folks think?

[roverp480]

I havnt any parts in front of me but the series 3 bell housing has an extra aperture for the clutch release lever and attaching the hydraulic slave cylinder . See attached picture I lifted off Ebay

Regarding your question regarding reverse gear etc. and Suffix letters. A number of the parts are not interchangeable between suffixes. but some are. I don't have any info as to which parts can go together. Theoretically if the casing part number stays the same one should be able to fit any set of matched parts inside . I say theoretically , having worked for Land Rover, as I have come across parts that haven't followed the part numbering system correctly. Personally I would go for getting all the correct parts for the suffix letter on your main casing .

[vlad_d]

I will have to check what's on my truck now. The plot thickens...

Also. I don't know why am I so excited by a pic of a rusty transmission on a pallet in the woods ..but I am. Its a disease...

[vlad_d]

Week #3 [ Update ]
So I got my first round of parts for the outer gearbox in. Looks like they all fit. In classic Land Rover fashion, everything just takes 2 weeks to get to me by mail. But, the good news is most of these parts are still available new, with the exception of the gearbox casing. FYI.

This week, I went diving into the parts manual to look at what parts I need, and if I can benefit from any "upgrades" over the years. My thinking is : if I have to buy 100% new parts (I'm building a gearbox from scratch) then I don't have to worry about re-use. I can get whatever is needed to upgrade to the better part. I found some interesting stuff below...

Suffix part interchange - Layshaft
I've attached the pages from the Series 3 Official Parts Catalog on the Layshaft, for reference.


I'd seen in James Taylor's book above a mention that between the Suffix "A" and "B" Land Rover had beefed up the Reverse gear mechanism. Looking through the parts catalog, it shows 2 diagrams...but keen eyed readers will see that most of the part numbers are the same. So, that tells me that the only change in the Layshaft assemblies is the Reverse shaft. Looking at the next page, there is a "Reverse Modification Kit" that seems to fix the Suffix "A" issues, and upgrade the weakness. The difference in parts comes down to they replaced a brass bush with a bearing. This made for a new reverse shaft and the reverse gear(where the bearing/bush fits into). Looks like the "Kit" just gives you the "B" shaft and reverse gear. The layshafts also are matched...so if you want the upgrade you need the "B" layshaft. All the bits in front of the layshaft are interchangeable between A + B. And the back bearing is the same. So, that tells me that the Layshafts are interchangeable in the case (A & B). So I'm going to order the "B" Layshaft and Reverse shaft, and basically have a "Reverse Modified Kit Suffix A"...or essentially a Suffix B innards. Seems that C kits are the same in this respect (the Layshaft), so this info applies to them, too. Only when you get to "D" suffixes do you get different part numbers, and I suspect that's more to do with the electroplating on the gear surfaces than dimensional differences.

I made up a parts order, and added it to the spreadsheet, here:

https://docs.google.com/spreadsheets/d/13FmnoIo10uMIkS4IwnY6APv2wqMbJN3mUgVcGm0W1q8/edit?usp=sharing

I'll let you al know how it goes, and appreciate any insights I missed.

[vlad_d]

Week 4(?)
I'm loosing track of time as I'm mostly just waiting for parts and paychecks to buy said parts. I DID get to do a bit more research and order most of the internals this week. I've updated the spreadsheet link above to include all Mainshaft components and gearing.

Mainshaft interchange
The manual shows interchange for A+B+C Suffixes for these components. So it was easy to order the right parts. Honestly, I don't know what the difference between a "B" and "C" Suffix LT76. On paper, they look to have the same parts. I'm building a "B" internals in an "A" case.

1 Ton
There are a few parts at the back of the Mainshaft that differ in the "109 1 ton", which threw me for a loop. I thought maybe I wanted a 1 ton gearbox internals thinking they might be "heavy duty"(Good!). Which is misleading. After some research, it turns out the gearing is lower on 1st gear in the 1 Ton(military vehicle). Some folks saying that if you fit the 1 Ton gears, you can't benefit from an overdrive, later. Well, that's an upgrade I hope to make, so I went with the standard LT76 parts. So, that's what's listed in the spreadsheet.

I ordered everything Monday, so now I wait. The only thing not available was one distance piece in an odd size. I guess there is exact endplay that is achieved by putting in the correct size distance piece and measuring with a dial Guage when fully assembled. If it's not in range, you take it apart and put the corresponding distance piece in(larger or smaller). Well, I can't find the middle one available anymore. But I've seen people just use a larger one and rub it on a flat surface with sandpaper to remove a few 0.001". So that's what I'll do. We'll see.

I'll post some pics when all the parts come in and I do some final assembly. All-in-all, I've spent about $2200 so far on all new parts. The original quote was for $3600 for a "rebuild"(who knows what parts re-used?). So, not cheap, but still cheaper than buying from someone already done, by about 30%.

[roverp480]

I am glad you didn't go with the 1 Ton parts as the mainshaft is different, to fit onto a modified transfer set of gears and they are not interchangeable . The 1 ton and Forward Control transfer box has dog clutches on both High & Low gears making it easier to engage low range on the move & it is sometimes refereed to as the "Easy Change" transfer . The standard box has dog clutch on high range but low is engaged by actually moving the gears into mesh. often referred as a crash change . The gear on the mainshaft sticks out further into the transfer box and thus an Overdrive will not fit as you have already ascertained.
I fell into this trap when I purchased a centre power take off for my 88" S2A and it didn't fit as it was off a 1 Ton.

[vlad_d]

It's been a couple weeks since an update, so I thought I'd post:

Week 6(?) Update:
My parts supplier emailed me two weeks ago to say some parts were on back-order. It was the synchos I ordered. I ordered Genuine Land Rover synchros. A bit more expensive, but I wanted Genuine for Two reasons:

1) I saw a Britanica Restorations video on YouTube where the guy showed he got some aftermarket synchro and the teeth were machined wrong. I'm not inclined to deal with that nonsense, so I paid the extra for "Genuine" Land Rover synchros.

2) My 3rd/4rth gears grind getting in. It's the whole reason I'm rebuilding this gearbox(at great expense in time and money). So...the hell am I going to get a cheap synchro again?

Anyways. A word of caution, the synchros seem to be kinda rare. Or, at least they don't keep them 'in stock' and usually drop ship them from Land Rover. So, beware of unexpected delays.

So, I'm shuffling around the garage waiting for parts for another week...

[vlad_d]

Week ~10 Update:

It's been a while since I updated here, but the gearbox build is still going. I've had some setbacks that required me to source additional parts. Details below:

1st & 2nd gears and Genuine 3rd Synchroniser.
After waiting 3 weeks for back-ordered parts from John Craddock, they inform me they just can't get my synchronizer in. They offered me a Baremach one. and I just don't trust them. Had one too many poorly machined parts from them. They offer to put an order in for me, but I declined. Speaking to Trevor over at RovahFarm and he tells me that he can order me one and that they are mostly being built out of Italy these days. I get nervous, having waited 3 weeks already for a part that a website said was in stock. I just don't want to risk drop shipment anymore. You either have it or you don't have it. No more of this "I can get it in 2 weeks" BS...So I found a supplier in Milan named 'Sivar' that makes the Synchro unit. Direct purchase through their eBay store and it came in 3 days. Wonderful! I don't know why I wasted 3 weeks with backorder.

Bell Housing and Clutch Release Mechanism
This one is a doozey. So, when I started this gearbox build, I sourced a bellhousing from ebay. Remember, I have a Series 3 with a 2.25 Petrol motor. So, I asked the guy selling the bell Housing if it will fit my engine, gearbox case, etc. The answer was yes. It DOES bolt on to both the engine and casting. BUT, it has an extra hole in the side of the belhousing. I didn't realise the implications of this. Basically, this is a 2a bellhousing. The clutch release mechanism is an older style mini-gear that pushes the clutch out when you twist a shaft that sticks out that hole in the bellhousing. Its a hold-over from the Series 1 that was a direct mechanical pedal that spun that shaft. Here are comparisson pics:

2a style:

https://littlegreenlandy.com/2019/08/10/gearbox-repair-6-clutch-release-mechanism/

Series 3 style

https://www.lrworkshop.com/diagrams/land-rover-series-3-clutch-and-flywheel/clutch-and-flywheel/clutch-clutch-release-mechanism-except-109in-v8_133

So, the difference becomes...I have to replace the whole clutch release mechanism, too. If I want to use this bellhousing. That's fine, I would have probably replaced those components anyway. But the issue is that I can't find the 2a parts! I don't have the 2a parts catalog, and searching for complete assemblies is near impossible without part numbers. I'm not even sure they sell/make new 2a clutch release mechanisms. At least, I can't find them. So, it comes down to this:

I can source all new Series 3 parts-they still make them(all the clutch parts). So, I'll get a new s3 Bellhousing. It sucks because I have a perfectly good Series 2a bellhousing I can't use. So, that's the thing to check before trying to mix-and-match 2a-3 parts. P/M me if you need a 2a bellhousing, I have a spare!

Everything else came in and looks good. Lots of little parts! Hope to get back to assembly when the new bellhousing comes in. I'll be sure to post pics of the new parts assembly.