Series 3 Gearbox rebuild advice

Hello,


I've finally stripped down my 109's gearbox and had a look at what needs doing. The synchros have been given a very hard time of it by someone. 3/4 is knackered and 1/2 has some missing teeth.

I've got a _long_ list of things to order but I have to say I don't know which parts to trust. This is going to cost a fair bit and I don't want to be ordering bearings to find they are rubbish. Please, if any of you lads have any experience of where to source gearbox parts please let me know.

Are all bearings replace on sight or am I best leaving well enough alone - most of the bearings seem ok.

I've started going through the list and looking on LRDirect but I have to say I'm a bit suspicious of their "OEM" stuff as much seems to be supplied by Britpart or Allmakes - can I trust LRdirect to have tested them? If not where is the best place to get gearbox bits? I know sometimes Britpart oil seals have turned out to be Corteco etc.

Are Bearmach any good for the gears and synchro parts? again, if not where to get them?

EAC Parts, anyone got any experience? http://www.shop4autoparts.net/Serie...ul-Kits/lt76mbk-o-haul-kit-lt76-main-box.html

Cheers

Dom

dominicbeesley said:

Hello,


I've finally stripped down my 109's gearbox and had a look at what needs doing. The synchros have been given a very hard time of it by someone. 3/4 is knackered and 1/2 has some missing teeth.

I've got a _long_ list of things to order but I have to say I don't know which parts to trust. This is going to cost a fair bit and I don't want to be ordering bearings to find they are rubbish. Please, if any of you lads have any experience of where to source gearbox parts please let me know.

Are all bearings replace on sight or am I best leaving well enough alone - most of the bearings seem ok.

I've started going through the list and looking on LRDirect but I have to say I'm a bit suspicious of their "OEM" stuff as much seems to be supplied by Britpart or Allmakes - can I trust LRdirect to have tested them? If not where is the best place to get gearbox bits? I know sometimes Britpart oil seals have turned out to be Corteco etc.

Are Bearmach any good for the gears and synchro parts? again, if not where to get them?

EAC Parts, anyone got any experience? http://www.shop4autoparts.net/Serie...ul-Kits/lt76mbk-o-haul-kit-lt76-main-box.html

Cheers

Dom

View attachment 106634 View attachment 106635 View attachment 106636

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there are no oem parts those factories shut down decades ago even if name still exists its a lottery now and choice is more likely supplier rather than manufacturer, you will need a 1st and 2nd gear in any case

jamesmartin said:

there are no oem parts those factories shut down decades ago even if name still exists its a lottery now and choice is more likely supplier rather than manufacturer, you will need a 1st and 2nd gear in any case

Click to expand...

I don't know how they get away with saying it (and charging for it) when it's not. Where do you get your gear parts from? Are the bearmach cos and synchros any good?

I got britpart synchro cones and the quality was awful. Bearmach and genuine ones were only ok (and suspiously similar).
I got mostly genuine parts where possible. If buying replacements, inspect and measure; if it's not good enough then ask for another. And keep going until you get a good one.

Edit. If you're replacing a lot, have you considered building it as a suffix d.

I was considering it but the shafts seem ok and I guess I'd have to replace the lot for suffix d. I may have a look at pricing it up as this box will be going in the daily drive so worth a bit of investment. This is my first go at a cog box so it's a bit overfacing!

I can vouch for EAC - I use them for everything. On their site you can usually choose between Timken or their 'Japanese or high quality European' option. I generally choose the latter.

Thanks, I've got a few bearings, seals and gaskets from them. The actual cogs and synchro's are a bit of a mixture of Bearmach and Genuine where cheap enough. The whole lot has come out rather more than I paid for the motor so I hope I don't balls it up. I will no doubt have to get some more bits for the shims and spacers later.

I decided against going suffix D on this one as, with the price of new shafts as well as gears it was getting a bit daft. If this one works out I may do the next box to Suffix D spec as once I've done this one and swapped it I'll be doing another...

D

Well, I've got part way there now.

Most of that parts that have come seem to have been of good quality, won't really know until the gearbox is fitted to the motor.

Everything went fairly straightforward except I wasn't clear on the layshaft refitting instructions:

Firstly I didn't know what was meant by endfloat - the float between the washer and the bearing (which is what I guessed) or float of the whole shaft to the rear bearing - if it is that then it is a bit out! Do any of you guys know (I ended up with the middle of the three distance pieces).

Also point 25 says 60lbft, everywhere else (data at front of manual and another place I cant find again) it says 50lbft?!

The only problem I have had was that the RTC1412 bearing delivered by LRDirect (an Allmakes OEM attempt) was nothing like correct - looks like an incorrectly labeled or badly printed package

From LRDirect:


Correct bit from Shop4AutoParts



The whole thing seems a bit clanky with a fair bit of lash in neutral but not having anything to compare it with I'm not sure whether that is normal?!? It doesn't look or feel to be too bad when a gear is engaged.

Engaging gear is a bit of a struggle with the top cover on so I need to have a look at that as something doesn't feel right - reverse seems to be the worst - I suspect it is something simple like the selector seal retainer plates snagging...Next up transfer box...

Anyway here's some pictures of the various bits going together in no particular order, I'm afraid I wasn't very good a taking pictures, I didn't want to get my phone too mucky!

Gearbox and front output casings cleared up, new bearings and seals


Test fitting the sleeves and distance pieces for the arse end of the mainshaft. The washer that was on already worked ok (Otherwise would have been a right bugger to get out). I had to sand down one of the bushes by about 2 thou




Mainshaft all built up and ready to put back in the box. This is a right royal pain of a job. Getting the first gear past the reverse gear without the inner sleeve, rear distance piece and the synchro cone all going walk about whilst holding the reverse gear out of the way and guiding the shaft out of the back with two hands stuck in an unbalance gearbox is no fun. I spent an hour on my first attempt before going home in defeat with bleeding hands and a raging thirst. Rigging a wooden frame and holding various parts together with generous dabs of grease helped in the end but it still took a few goes. (Not helped by dropping the needle bearing and losing one of the rollers in the mess on the floor).


Bellhousing front all ready to go back on after a few test-fits with the various layshaft distance pieces. This is the part that I am least sure of.



Back together..

Finished...

Check end float with a dial gauge measuring the in out play of the lays haft. There should be a tiny bit.
Put the transfer box on just so you can get the main shaft nut tight. Then check all the gear engage and the shafts turn. If there are incorrect clearances, it can have two gears engaged and the shaft won't turn. (Don't ask how I know that)
It may be easier to test it with the top cover on, just shove the selector forks around.

Thanks Don, was what I was hoping to not hear...how much is a tiny bit - I didn't measure it but I'd say there was a good 10 thou

PS I got the MS not fairly tight...with a chisel and by locking up with reverse and a forward gear selected...new nut on order and I will search for the bloody MS nut tool, constantly on hand until you need it whereup it disappears.

Can't actually find a figure. Best I've got is minimal. Mine was 1 thou. End float is important on the gears because too much means jumping out of gear.
Not too sure whether the lays haft is as critical, however I machined down the bigger distance piece to get ten minimal float.

end float for 1st 2nd and 3rd gears is vital needs to be at least 2 thou but not greater than 8

Thanks James, I got the float between the gears on the mainshaft more or less in the middle (5 I think) after a bit of headscratching and juggling about which bushes to rub down. It's just the layshaft bearing endfloat that might be out. Still not had a chance to check...

D

dominicbeesley said:

Thanks James, I got the float between the gears on the mainshaft more or less in the middle (5 I think) after a bit of headscratching and juggling about which bushes to rub down. It's just the layshaft bearing endfloat that might be out. Still not had a chance to check...

D

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i wouldnt worry about that theres no endfloat when you tighten the l/s bolt up use loctite and check the other end through the 2 holes rollers are seated nicely in the brg race ie not too far forward

Well I'm almost there, I ended up spending a bit more time and a lot more money on this than I'd first bargained. I've not had as much Landy time recently, having a toddler around the house takes up a lot of time and she's pigging useless as an assistant in the garage...complains less than the missus though

A couple of sticking points:

I need a new filler/level plug for the T/box, I've looked it up and it says part 3292 for the one in the side of the gearbox, none marked in the catalogue for the t/box one. I've now bought two 3292's one from ebay one from LRDirect (Bearmach) and both are the same, they're straight cut instead of tapered and wont' fit! see photo below, anyone know where to get a proper one?

There's a slight sticking point when rotating the input shaft by hand, it's slight and can be overcome with my weedy wrists but I'm worried I've got something wrong, I'm gonna bung it in and see how it goes anyway...if I can find filler plugs that is!

I've still got the front output housing and 4wd bits to do but they all look to be in good nick...

1/2" or 3/8" BSPT plug most plumbers merchants will stock it.
Measurements of threads here
https://www.newmantools.com/taps/bsp.htm

Thanks Blackburn

I thought I was going to have to get access to a lathe! I completely buggered the old one getting it out then stupidly threw it away!

D

Make you wonder, did they change to straight cut at some point and if so why use the same part number!?! Thanks to your pointer I've got some ordered.

Thanks

Dom

I got the radiator plugs and they fitted perfectly! Now a slightly bigger problem. In "tapping out" the output shaft it appears I may have been a bit over-exuberant (it was a right c**t to get out) and I've buggered the front-end of it...new one ordered (what's another £100 anyway) and looking forward to another t-box rebuild. I'll try and remember to get some pictures this time