Author Topic: Gearboxes/Transfer Cases/ Overdrives  (Read 493 times)

Offline S210912j

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Gearboxes/Transfer Cases/ Overdrives
« on: 26 February 2015, 09:54:56 am »
Still not had the Landy arrive...  :banghead

But.  Am thinking about gearing, at the moment it's a non O/d vehicle.

I'm not keen on an O/d to be honest, they seem 'kin expensive and the parts available would concern me.

So that leaves 2 options.

Ashcroft high ratio transfer case.  Has anyone got one?  What are they like?  Landy will be running a 2.5 n/a diesel (when it bloody arrives) with 7.50 tyres.  Am I going to suffer on hills?

Or

Fit a replacement gearbox, I keep an eye on things like the LT95, as they seem to come up with O/d's quite cheaply.  Could I put one of those onto a Series Transfer case?

Any advice appreciated.

Offline Serious Series

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #1 on: 26 February 2015, 02:07:46 pm »
Where abouts are you located. I am in tyneside area if close enough you can come have a drive.
I have Ashcroft high ratio transfer case in my 200DI and I really like it.
Currently running 235 70 tyres which are 2" smaller in diameter than 7.50s
Had overdrive on with 2.5 15J engine and used to cope ok tyres at that time where 205 which are same diameter as current ones.
1972 Series 3 SWB with 200DI engine and Ashcroft high ratio transfer case. Chris Perfect parabolics , galvanised chassis , galvanised rebuilt bulkhead [by me] , galvanised slam panel. Desperately in need of a repaint.
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Offline divie

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #2 on: 26 February 2015, 02:45:16 pm »
^^^^ Nice offer from SS above. I really think that you should drive it for six months or more and sort out all the other issues a series landie will present you with !! Only then consider messing around with the gearing. Do the maths. Ashcroft high ratio/overdrive and 3.54 diffs all give around 25/28%  I tried 3.54 diffs in a 2.25 88" diesel. Soon went back to 4.7s you need a good petrol or 200tdi up front to pull taller gearing. The 2.25 diesel lost all "driveability" didn't like hills or to many downshifts to 3rd on an old gearbox.

Offline S210912j

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #3 on: 26 February 2015, 06:54:14 pm »
Sage words guys.

SS, that's really, really kind.  If I'm ever up your way I'll take you up on that!

I'm based in East Anglia though, so it might not be until the summer road trip... :)

It's running a 2.5n/a, so will that discumknackerise the 'drivability'?  My last Landy was a straight six, so had acres of torque to play with.

Offline Doug_T

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #4 on: 26 February 2015, 08:15:24 pm »
It's a lot more work, but the 2.5 NAD and LT77 main box combination works really well. You would of course have to either use the transfer box and diffs from the donor vehicle, or one of those Ashcroft adaptors that bolt it to the Series transfer case. There's a great writeup of the former method on this site.

LT95 will not fit to the Series transfer case, neither will the overdrive from said box.
"Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, Champagne in one hand- strawberries in the ot

Offline divie

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #5 on: 26 February 2015, 08:30:40 pm »
S210912j I to ran a 6 pot back in the day, 14 tank fills towing from Brum to Aberdeen ! Slighty less with an empty trailer coming home. After that it was a 2.25 series 2a diesel and diesel ever since, miss the torque though.

Offline NoelC

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #6 on: 03 March 2015, 11:11:22 pm »
The best advice is drive one with the setup you're considering before doing anything. I would think a 200di would be a bit gruntier than a 2.5 N/A and personally I wouldn't want to have increased gearing I couldn't change out of (i.e. overdrive) unless it's an 88 with small tyres perhaps.
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Offline S210912j

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #7 on: 06 March 2015, 10:52:10 am »
Thanks all.  You've given me lots to think about.

The current train of thought is...

It's a soft top, so it's not hauling about a huge amount in terms of weight (compared to a s/w) so that might help?  Although, what's the difference between a 110 with a 2.5na and 5 speed box, and a series box, running 3.5:1 diffs? 

(forgive me if that's a really ignorant question)


Offline Doug_T

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #8 on: 06 March 2015, 08:11:11 pm »
The transfer box high ratio in the one ten will either be 1.4:1 or 1.66:1, whereas the Series ratio is 1:1. Effectively the overall final gearing is practically the same due to the one ten's diffs being higher ratio (3.54:1 vs 4.7:1).

Kind of makes sense if you think about it; the 2.5 NA engines have only a few more horsepower and lb/ft than the 2.25's - in heavier vehicles - so the gearing can't be too different.
"Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, Champagne in one hand- strawberries in the ot

Offline NoelC

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #9 on: 06 March 2015, 08:48:42 pm »
(forgive me if that's a really ignorant question)

Not ignorant at all, as Doug says the boingys got standard diffs (3.54:1) and the transfer box ratios varied depending on engine.

Ashcroft's ratio calculator http://www.ashcroft-transmissions.co.uk/calc/ratio_calc.html is excellent for fiddling with combinations.
'55 107 truck cab ✪ '66 109 hardtop ✪ '66 109 LHD ex-MOD ambulance ✪ '71 109 one ton ✪ '72 88 2.5 petrol ✪ '72 2B FC Dorothy Perkins 4.236 ✪ '79 Lightweight LHD ✪ '79 109 LHD ✪ '83 109 FFR ✪'93 Dennis Rapier fire engine ✪'94 Range Rover Vogue Tdi...and an '86 SAAB 9000 turbo

Offline spitfiremk1uk

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #10 on: 07 March 2015, 12:15:50 am »
I would suggest you keep the standard gearbox and gearing and if you are considering using 7.50s or 235/85s or bigger consider a 1 ton gearbox which will have slightly lower tatios still.

The 2.5 is slightly better than the 2.25 but you have to keep perspective. Consider a decent exhaust system and K n N air filter and use the coolest air possible as a baseline.

I have an ashcoft transfer box. Very high ratio, slightly higher than a fairy overdrive in fact. Great for a good 2.5 petrol, tdi or v8. I do not recomend it for your application. A fairy overdrive is expencive these days but keeps your gearing standard and you can opt for the overdrive gear when driving downhill and a tailwind.

110 NA 2.5 diesels all came with 1.666 transfer box ratios so that they could pull 7.50 tyres. Higher ratios make the car embarassing to drive.

lt95s are made for rover v8s only and have a selection of transfer box ratios nothing from these boxes fit inside the landy 4 speed box.

All lt230T transfer boxes are permenant 4x4 and are a lower ratio meaning when high ratio diffs are used they are similar to a leafer landy gearing. fitting 3.54 diffs to a leafy messes up both the high and low range so that rules out that change in my eyes.

My suggestion is to live with the fact it is an underpowered engine so it will drive slowly. If you want to tow or have a little extra grunt use a 1 ton gearbox for an even lower high and low range. Have fun.

Offline niteram

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #11 on: 08 March 2015, 10:45:48 am »
as said ^^^^^ I think you should drive it for a while and see what you think.
in reality overdrive will only reduce the revs at top speed, making the driving experience a bit quieter! it may give you a couple more mph on the flat.
my previous SW was 2.25 petrol with O/D and although the engine was good I very rarely got to the speeds where the O/D was needed.
I now have a similar SW with Tdi power, which is a totally different drive. but that's a totally different topic  :rolleye0012:
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Offline S210912j

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #12 on: 09 March 2015, 11:46:24 am »
Cheers spitfiremk1uk. 

I invite you to tell me I'm wrong, and you do...   :handbag 


(joking, thanks for the advice!  ;D)

Niteram, to be honest, it's just for some of the longer journeys we'll be doing in the Landy, just to reduce the ear bleed induced by 3 hours on a dual carriageway...


Offline DarrenH

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #13 on: 11 March 2015, 12:55:44 pm »
my swb has 750 tyres and fairey overdrive.  in 4th it will sit at 60mph (actual) with no issues with more left in reserve if you were mad enough, revs are a too high for my liking though (more so if it were a diesel)   with over drive engaged it knocks the revs down nicely and will still accelerate believe it or not (on flat of course)

at 70 in OD the mixture of aero/engine/drive train noise just doesn't "feel" right, i never do it, but just wanted to share my experience and that do not agree it swamps the engine.

like most folk i only really use it as a 5th gear, tend to engage it anything over 40 for pootling along.   or the other times when deliberately boring people to death about how its now got 16 forward speeds then unnecessarily (and smugly) going 1st, 1st OD, 2nd, 2nd OD

Offline Arjan

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Re: Gearboxes/Transfer Cases/ Overdrives
« Reply #14 on: 11 March 2015, 10:34:46 pm »
Hmm...

We have a - tired now - 2.5 N/A diesel in the SWB Hybrid and that will be replaced late this year / early next year by a 200 Tdi on the standard Series gearbox.

Why ?

- 200 Tdi starts so much easier than the 2.5 N/A
- 200 Tdi has more torque and makes for easier driving
- 2.5 N/A is slightly more powerful than the 2.25 diesel but not really that much a difference

We had a 2.25 Turbo diesel in the Hybrid before the 2.5 N/A went in and TBH, I'd just aswell rebuild the 2.25 Turbo had I had the time then.

Like said - drive a converted vehicle before parting with money / starting the conversion.