Imagination Required - Gearing a Mog

[Astro_Al]

Hi folks, need some off the wall thinking to sort the gearing on my Mog.

Looking at an R380 and LT230 with the 2.8 isuzu. On my current tyres (like to keep them if poss) with a 1:1.003 LT230 I'd need about 20% more (overdrive) gearing to get to comfortable 'cruising' revs (aim for 2750rpm in 5th gear).

Everything I read about LT230 overdrives tells me they fail and are expensive (anyone tried or know the price of that new one being made in the UK?).

So I'm thinking about alternatives. Moglite suggested either doubling with another LT and running it in reverse (say a 1:1.2 running in reverse would give the right increase), maybe the rest of the carp could be removed and just the relevant gears kept to keep it smaller. 3 speed LT230 anyone? Any issues running it input/output reversed?

Any other ideas most welcome. Am I being unfair on overdrives - it would solve the prob if they were any good, and reasonable cost?

Thanks for any inputs.

Al

[Turbocharger]

Al,

Despite having an LT230 in the floor I know nearly nothing about their innards, so read on with this in mind.

It strikes me that a 1:1.003 tbox driving a reversed 1:1.2 box would give very similar gearing to just the reversed 1.2 box, or even the 1.2 box with the guts upside down in the same case. I don't know if there's clearance inside the casing (ISTR it's a parallel box) or how you'd carry the bearings, but it seems that putting gears in a box is less work than turning and mounting the whole box, and more elegant than another one nailed on upside down.

Food for thought?

[simonr]

There has bee a lot of discussion about how to reduce the gearing on Suzukis on Difflock and the like.

One of the solutions was to use a planetary reduction box found on forklifts - and fit that in between the gearbox and transfer box. Something like that mounted in reverse might do the trick? IIRC they were pretty small - but designed to handle decent torque.

Another option could be to use a hub reduction box from an agricultural vehicle?

Yet another would be to buy an old transfer box and make your own casing for a selection of gears? Or use a multiplex chain drive from a motorcycle (similar to Borg Warner boxes). At least with a chain drive, the tolerances required are lower so you could easily make a casing (laser cut?) without resorting to precision milling.

Si

[bill van snorkle]

Hi folks, need some off the wall thinking to sort the gearing on my Mog.

Looking at an R380 and LT230 with the 2.8 isuzu. On my current tyres (like to keep them if poss) with a 1:1.003 LT230 I'd need about 20% more (overdrive) gearing to get to comfortable 'cruising' revs (aim for 2750rpm in 5th gear).

Everything I read about LT230 overdrives tells me they fail and are expensive (anyone tried or know the price of that new one being made in the UK?).

So I'm thinking about alternatives. Moglite suggested either doubling with another LT and running it in reverse (say a 1:1.2 running in reverse would give the right increase), maybe the rest of the carp could be removed and just the relevant gears kept to keep it smaller. 3 speed LT230 anyone? Any issues running it input/output reversed?

Any other ideas most welcome. Am I being unfair on overdrives - it would solve the prob if they were any good, and reasonable cost?

Thanks for any inputs.

Al

One of the Mog axle conversion specialists in Canada (Exact?) ran a Chevy pickup on 404's with an extra NP205 transfercase mounted back to front and when low range of this box was engaged an overdrive ratio of close to 1:2 was produced to raise the overall gearing. That ratio seems a bit extreme to me, and doubling up transfercases is a bit messy. I'd rather see say a suitable compact car gearbox mounted back to front and fitted between the engine and the trucks main gearbox. When mounting any gearbox back to front you must make certain that drive thrust is applied against a bearing and not a circlip, and the front of the mainshaft that in many cases has a parrallel roller bearing to support it inside the input shaft should be altered to a tapered roller bearing. Although a fair amount of work is involved you could cut down an turn around an old LT95 gearbox and just use 3rd gear and direct drive as shown on http://forums.lr4x4.com/index.php?showtopic=6428&st=60 on post 73 to give a 35% lift.

Bill.

[will_warne]

There has bee a lot of discussion about how to reduce the gearing on Suzukis on Difflock and the like.

One of the solutions was to use a planetary reduction box found on forklifts - and fit that in between the gearbox and transfer box. Something like that mounted in reverse might do the trick? IIRC they were pretty small - but designed to handle decent torque.

Another option could be to use a hub reduction box from an agricultural vehicle?

Yet another would be to buy an old transfer box and make your own casing for a selection of gears? Or use a multiplex chain drive from a motorcycle (similar to Borg Warner boxes). At least with a chain drive, the tolerances required are lower so you could easily make a casing (laser cut?) without resorting to precision milling.

Si

I'd say Si's first idea is spot on - divorce the t.box and put a planetary gearbox in between. Obviously finding the right ratio will be the tricky bit but that shouldn't be impossible. You could run a reversed BW t.box planetary gearbox if you really got desperate but the step up would be a tad silly.

[bill van snorkle]

I'd say Si's first idea is spot on - divorce the t.box and put a planetary gearbox in between. Obviously finding the right ratio will be the tricky bit but that shouldn't be impossible. You could run a reversed BW t.box planetary gearbox if you really got desperate but the step up would be a tad silly.

Any planetary assembly such as a hub reduction or forklift reduction will be more than stong enough but have a silly step up ratio when reversed, and may be rather noisy due to probably having straight cut gears. Many automatic transmissions contain planetary gearsets that would give the desired ratio. A suitable diameter piece of pipe could be used to fabricate a compact housing to contain it, but it must be remebered that they were only ever designed to receive engine torque, not engine torque multiplied by first gear ratio of the main gearbox. Fitting such a unit between the engine and main gearbox probably involves no more engineering work than fitting it between the main gearbox and transfercase, and offers a couple of possible advantages. Number 1 would be that a relatively light and compact planetary can be used. 2, It may be possible to shorten the bell housing so that the planetary doesn't increase the overall length of the transmission too much.

3, The planetary is always revolving in the same direction so any end thrust issues can be more readily accomodated .

4, Due to the relatively low input torque involved, altering input and output shafts by annealing, resplining, or even cutting and grafting by welding is much less critical from a strength perspective than if the overdrive unit were located between the gearbox and transfercase.

Bill.

[dirtydiesel]

Why not just fit 411 portal gears, to give 6:1 in the axles?

[bill van snorkle]

The ''Edit'' function expiring a hour after posting unfortunately makes for multiple postings on technical matters such as these.

At the rate older vehicles get scrapped these days, I wonder if it's still possible to findan old Laycock DeNormanville overdrive that were optional on Ford Zephyrs,MGB's, Rover cars etc. These units were about the size of my fist and fitted inside a replacement tail housing at the back of the original gearbox.These IMO would be ideal for fitment in front of the R380. You may even be able to incorporate them inside the bell housing instead of shortening it.

Could this be an exciting new product for X Eng or Ashcroft Trans ? Royalties can be paid into my retirement fund on top of the 50 cents that is already in there.

Bill.

[bathtub]

Hi folks, need some off the wall thinking to sort the gearing on my Mog.

Looking at an R380 and LT230 with the 2.8 isuzu. On my current tyres (like to keep them if poss) with a 1:1.003 LT230 I'd need about 20% more (overdrive) gearing to get to comfortable 'cruising' revs (aim for 2750rpm in 5th gear).

Everything I read about LT230 overdrives tells me they fail and are expensive (anyone tried or know the price of that new one being made in the UK?).

So I'm thinking about alternatives. Moglite suggested either doubling with another LT and running it in reverse (say a 1:1.2 running in reverse would give the right increase), maybe the rest of the carp could be removed and just the relevant gears kept to keep it smaller. 3 speed LT230 anyone? Any issues running it input/output reversed?

Any other ideas most welcome. Am I being unfair on overdrives - it would solve the prob if they were any good, and reasonable cost?

Thanks for any inputs.

Al

I run an under drive with mine & just run in high range with the under drive engaged it gives me roughly the same speed as a standard LR in low box & **** me about 1 mph in low & low !!But that does depend on what size tyres you run really.

For what its worth ive got a modified LT230 ,a 3 speed 350HP & 44 Boggers & it semms to hold up ok but then i am a careful technical driver

I am still looking at having a set of ring & pinions made for mine they are quoting approx £1500 a full set for 10 sets if we can get enough people interested i will have 2 sets.

Also spoke to Atlas Requesting a box to fit my truck & they advised me if i did the mods to the LT230 i have then it would be comparible strenght to the Atlas??

Peter

[bathtub]

I run an under drive with mine & just run in high range with the under drive engaged it gives me roughly the same speed as a standard LR in low box & **** me about 1 mph in low & low !!But that does depend on what size tyres you run really.

For what its worth ive got a modified LT230 ,a 3 speed 350HP & 44 Boggers & it semms to hold up ok but then i am a careful technical driver

I am still looking at having a set of ring & pinions made for mine they are quoting approx £1500 a full set for 10 sets if we can get enough people interested i will have 2 sets.

Also spoke to Atlas Requesting a box to fit my truck & they advised me if i did the mods to the LT230 i have then it would be comparible strenght to the Atlas??

Peter

Any other solutions as i may need to run smaller tyres???

[Astro_Al]

Current thinking is as follows:

I have an Atlas and an NV4500 sitting here, so I may as well use them. I just got an Isuzu 2.8 td for it (with gearboxes if I want to use them).

I suppose ideally I'd come up with some kind of overdrive right behind the engine, which would output into the NV4500. Still no closer to deciding what will be reliable and durable (and cheapish). Still thinking to be honest.

I have heard that it might be the rings & pinions which are different in the 411 axles, not the portal gears. Either way, I'm not going down that route. I'll use something more easily replaced.

Moglite suggested a chain drive box, so sprockets could be changed easily-ish to alter the ratios if needed.

I think a chopped down extra gearbox is looking likely at this point.

Cheers, Al.

[FridgeFreezer]

Atlas & NV4500 to sit behind a 2.8TD, anyone for overkill? Why not go the whole hog and stick an LSx in the front, economy will be about the same, you'll have parts commonality with whatever you're not building, and you might actually crack a decent speed without adding sails to it. I know the 2.8 is a good unit, but it's a lot of car to move about especially when loaded. Stick the 2.8 in your Rangey as a parts chaser and give the Mog some proper LS love.

[Astro_Al]

Hmmm, so a stout light-truck gearbox is overkill in a light-truck, but an LSx isn't???

I think the gearbox is well suited to a Mog, and I've got it sitting about so its free. The Atlas outputs match the torque tubes reasonably well, I can clock it, its strong, has a hand brake and it mates to the NV.

I'm not shipping over an LS for this thing, I just need a simple ratio adjustment. The 2.8 with a nice big intercooler will be plenty for what I want.

Al

Atlas & NV4500 to sit behind a 2.8TD, anyone for overkill? Why not go the whole hog and stick an LSx in the front, economy will be about the same, you'll have parts commonality with whatever you're not building, and you might actually crack a decent speed without adding sails to it. I know the 2.8 is a good unit, but it's a lot of car to move about especially when loaded. Stick the 2.8 in your Rangey as a parts chaser and give the Mog some proper LS love.

[FridgeFreezer]

OK, maybe I should've said the engine would be underkill sitting in front of all the other well-matched components happy now?

[Astro_Al]

happy now?

Well, it makes more sense, but I'm not going to agree with you! I'm doubling the BHP and torque from standard as well as lightening the Mog considerably (so far I've chopped off over 1/2 a tonne of steel without trying!), so I don't think I'm going to be having power problems with it.

Now... The gearing...

AL

[FridgeFreezer]

Bigger tyres!

[TRMV8]

An atlas high range is 1:1 so why not cut some custom gears go go higher???? They will fit.

[steve b]

Hi Al,

Got the prop flanges ta....are you sure you don't need them if you are going to use the Atlas? how are you planning on mounting the torque tubes to the gearbox? the tensile/compression loads must fairly high with the std mog setup...

....anyway back to your Q , I'd be looking for some sort of industrial/agri annular stepperbox.

Hope to do Billing for a day so might catch up there....I'm sure I'll find myself on the Shires Stand at some point

Cheers

Steveb

[Astro_Al]

Tim - I was considering it. Would be more elegant than another separate gearbox.

Steve - howdy, glad to hear it, I thought they might get lost in the panic!

Yes, I reckon I'll pop up for a day too, so I'll see you there, hopefully with some progress to report!

Regarding the torque tubes. I want to keep it all standard if poss, right up to the gearboxes, so the plan is to create a subframe that mimics the gearbox torque-tube interface, and just run the propshafts up to the transfer box outputs. The loads should go from the torque tubes into the

chassis if I've planned it right. (!)

Anyone know anything about getting gears cut?

Cheers, Al.

[FridgeFreezer]

Anyone know anything about getting gears cut?

Drop me an e-mail old bean

[dirtydiesel]

I have heard that it might be the rings & pinions which are different in the 411 axles, not the portal gears. Either way, I'm not going down that route. I'll use something more easily replaced.

The difference is definatly in the portal gears, the diffs are the same 411-404.

if you use an lt230 the front output will be on the wrong side.

[Astro_Al]

Ok, must be the other guy who's wrong then. Anyway, I don't have any and they never seem to come up.

Yeah, I realise that about the LT, thats partly why I'm looking at my Atlas instead.

I think I may have found the solution in an overdrive unit designed for the NV gearbox... I'm investigating.

Cheers, Al.

P.S. - John, you're thinking of that place near you, aren't you?

[FridgeFreezer]

P.S. - John, you're thinking of that place near you, aren't you?

One of them, yes

[MogLite]

I think I may have found the solution in an overdrive unit designed for the NV gearbox... I'm investigating.

It it this one 0.58:1 double overdrive

[Astro_Al]

It it this one 0.58:1 double overdrive

Kind of, its the 'Ranger Overdrive' - the second one on that page.

Al.