Series 3 with 300 tdi

Gsxr1340 · Feb 14, 2021

hi all. I've recently brought a 3 series 88". With a 300 tdi mated to original gearbox etc. Is it possible to fit a more modern gearbox and transfer box. It's got a galvanised chassis is there anyway to bolt up gearbox etc without cutting or welding. I'm a confident welder if there's no way other than welding. Any info be great
Cheers dave

tottot · Feb 14, 2021

Can't see why not. I once fitted a V8 and lt95 into a series one 80, bit of a squash to say the least. Not sure how a 300 would fit a 3 gearbox, perhaps with the clutch housing from a 200. Any way a lt77 or r380 would likely just need holes drilled in the chassis rails for the gearbox mounts.
Next problem is the front axle that has no CV joints to cope with the permanent four wheel drive of the L230 transfer box. However there was a way of making it two WD [ 4WD only off road ] like a series. Another way would be to mod a defender front axle to mount on the leaf springs and also fit defender diff in the rear axle for better gearing and turning circle

jamesmartin · Feb 14, 2021

only gear box that would fit are the short defender 77s or the stubby r380 then its a ting rear prop if you use the lt230, though you can get conversions to fit the series t box

rob1miles · Feb 14, 2021

Are you sure you bought the right vehicle for your needs? When it comes to modernising a Series everything is possible and most of its been done, but a lot has been a waste of time and for everyone trying to add something there someone trying to get it all off. You don't say what year, but if its close to historic be careful on the points or it will cost a lot more than the parts and labour. The general rule seems to be "major modification" does not include a TDI, but once you change the transmission, add synchro and full time 4WD plus CVs its a "yes" and that can be expensive. You can fit a Land Cruiser transmission, inc transfer case and axles, (its been done) but next thing you'll want to fit the Land cruiser body (its got comfy seats, a decent heater, a radio) the engine (its got more power), which brings me back to my first question, if you don't like the engine or transmission are sure you have the right vehicle?

lynall · Feb 15, 2021

Iirc coiler axles are wider than leafer axles.

Edit to add, the series gearboxes arent bad at all, if yours is all synchro all you are going to gain with a 77/380 is another gear.
I assume the car has the coiler diffs?

Gsxr1340 · Feb 15, 2021

rob1miles said:
Are you sure you bought the right vehicle for your needs? When it comes to modernising a Series everything is possible and most of its been done, but a lot has been a waste of time and for everyone trying to add something there someone trying to get it all off. You don't say what year, but if its close to historic be careful on the points or it will cost a lot more than the parts and labour. The general rule seems to be "major modification" does not include a TDI, but once you change the transmission, add synchro and full time 4WD plus CVs its a "yes" and that can be expensive. You can fit a Land Cruiser transmission, inc transfer case and axles, (its been done) but next thing you'll want to fit the Land cruiser body (its got comfy seats, a decent heater, a radio) the engine (its got more power), which brings me back to my first question, if you don't like the engine or transmission are sure you have the right vehicle?

Thanks for info. I have brought the right vehicle love it. Just changing diffs to 3.54 as the rear was shagged and props have wear too. I was just asking if there is a good way to update gearbox. I will see if the diffs make any difference to the bad noise it had hopefully be all good and I can leave it alone. Thank you for your advice and it’s 1973 so I don’t want to lose the historical part. Cheers davev

tottot · Feb 15, 2021

How is your present gear box ? Does it change well [ not sports car quick, just smooth and easy ] Is it noisy [ most series box's whine or groan a bit and a few are quiet ] Only with a petrol engine do you get to notice this much. Internal gearbox rattles are not good. If you are having problems the an overhaul would help. In the mean time change the oil while you try out the diffs. An overdrive would give you extra gears but good ones are are now hard to find.

lynall · Feb 15, 2021

Gsxr1340 said:
Thanks for info. I have brought the right vehicle love it. Just changing diffs to 3.54 as the rear was shagged and props have wear too. I was just asking if there is a good way to update gearbox. I will see if the diffs make any difference to the bad noise it had hopefully be all good and I can leave it alone. Thank you for your advice and it’s 1973 so I don’t want to lose the historical part. Cheers davev

Diffs make a huge difference.
When i first fitted my tdi the thing would top out at 55/60mph in top with the engine at or beyond its rev limit, diffs meant it would do 80 (probably do more) which is surreal as the thig sort of floats and is not connected to the road, never done it since!
Early 3.5 diffs have the filler on the diff casing itself like the series diffs, later ones rely on the axle filler only.

Gsxr1340 · Feb 15, 2021

tottot said:
How is your present gear box ? Does it change well [ not sports car quick, just smooth and easy ] Is it noisy [ most series box's whine or groan a bit and a few are quiet ] Only with a petrol engine do you get to notice this much. Internal gearbox rattles are not good. If you are having problems the an overhaul would help. In the mean time change the oil while you try out the diffs. An overdrive would give you extra gears but good ones are are now hard to find.

Hi it was hard to tell as the noise was quite bad hopefully from the diffs. It’s did get gears ok. I tried it on stands with props off and was fine but it’s not under load so fingers crossed all ok. It’s got a overdrive unit too. Going do oil on all before try it out. Cheers mate

Series 3 with 300 tdi

Gsxr1340

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tottot

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jamesmartin

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rob1miles

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lynall

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Gsxr1340

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tottot

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lynall

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Gsxr1340

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