Available Ratios

[mcrover]

What ratios are out there for what Diffs/ Transfer cases as far as Rover parts goes not after market, what is rare and what is not.

It seems that 3.54 and 4.11 diff gears seem to be the only ones really talked about in the Rangie/Disco world, I want to know if there are other combos around even if they arnt popular or if they're rare.

If there has been a thread like this before, can some one point me in the right direction with a link.

Thanks

[DaveS3]

Standard Rover you can get KAM 4.75 diffs I believe.

If you do Toy centers, you can get up to 4.5 easily in Australia, then possible 5.29 if you start buying HP R&P's from the states.

In HR you can only buy whats available standard from RR/Disco?Defender if we are talking LT230, but Maxi and Ash croft both make lower LR kits of which some reduce HR as well.

Dave.

Google KAM & Ashcroft. They will give you a good idea but both are in the UK.

[JDNSW]

The two common ratios are 3.54 (Rangerover, Disco, 90/110/120/Defender except 6x6, and S3 Stage 1 V8 and Isuzu) and 4.7, not 4.75, (all Series except Stage 1 and very early Series1 + 110 6x6) As far as I know, except for the Series 1 up to late 1948, no other ratios have been fitted by the factory - changes in transfer ratios seem to have been preferred.

John

[DaveS3]

Yes Series rovers are 4.7 but KAM sell 4.75's as an after market center.

Going from 3.54's to standard rover 4.7's is going backwards in strength.

Dave.

[Tusker]

http://www.expeditionlandrover.info/gear_ratio.htm

That'll take a day or two to digest

Regards
Max P

[isuzurover]

As mentioned - LRs came with 3.54:1 and 4.7:1
Some rover cars had 4.1:1 (or 4.11) I believe. The aftermarket 4.11s are copies of this, but I believe some are reverse cut for extra strength???

The series 4.7 is 47 crownwheel teeth and 10 pinion teeth. The pinion head is small and the teeth thin, which makes this a weak ratio (compared to 3.54). For this reason there are some aftermarket places that make 38/8 tooth centres = 4.75:1, which are much stronger, but probably only about the same as a stock 3.54 (or maybe not even that).

The Perentie 6x6 is fitted with a "special" 4.7:1 ratio. AFAIK it still has 47/10 teeth, but is reverse cut and beefed up (because early perenties kept breaking the series 4.7 centre). It only bolts to a coiller centre, and when I priced it was $1700 for 1 ring and pinion!!! :eek:


As for t-case ratios - I assume you mean LT230?
Stock low range is 3.32:1 That's it. Maxi Drive make 2 lower ratios - 4.5:1 is the lowest (I think) anyone know the other?
High range - stock ratios are: 1.003:1 (county 3.9 and some rangies), 1.2:1 (Disco?), 1.4:1 (Defender), 1.57:1 (NA diesel ninety/one-ten - i.e. not in OZ)

[JDNSW]

...........
As for t-case ratios - I assume you mean LT230?
Stock low range is 3.32:1 That's it. Maxi Drive make 2 lower ratios - 4.5:1 is the lowest (I think) anyone know the other?
High range - stock ratios are: 1.003:1 (county 3.9 and some rangies), 1.2:1 (Disco?), 1.4:1 (Defender), 1.57:1 (NA diesel ninety/one-ten - i.e. not in OZ)

My 110 (LT95 not LT230) is 0.996:1. I don't know whether the gears are the same as in the LT230.

John

[isuzurover]

My 110 (LT95 not LT230) is 0.996:1. I don't know whether the gears are the same as in the LT230.

John

The gears are different, that is why the equivalent LT230 ratio is 1.003:1

[justinc]

Hi Ben,
A bit OT and Just a quick one, but my ex 110 4BD1 county LT230 had 1.211:1 High range, and this was factory as delivered. I have had it said in the past that some late 110 Isuzus had the 1.2:1 case due to lack of 1.003:1 Gear availability. have you heard this?
After fitting my 33's, and having 1.113:1 gears in the LT95, I reckon I can still run .996's and get good road and offroad manners.:)
JC

[isuzurover]

Hi Ben,
A bit OT and Just a quick one, but my ex 110 4BD1 county LT230 had 1.211:1 High range, and this was factory as delivered. I have had it said in the past that some late 110 Isuzus had the 1.2:1 case due to lack of 1.003:1 Gear availability. have you heard this?
After fitting my 33's, and having 1.113:1 gears in the LT95, I reckon I can still run .996's and get good road and offroad manners.:)
JC

I have heard it before - but I think it was from you??? Mine is a 1987 and it has 1.003 gears. Maybe availability is right? Or maybe owners complained about the gearing being too tall in 1st or 5th???

[justinc]

I have heard it before - but I think it was from you??? Mine is a 1987 and it has 1.003 gears. Maybe availability is right? Or maybe owners complained about the gearing being too tall in 1st or 5th???

Hmmm, Do you think your 1st is too tall? I haven't driven any others with the 1.003's. All my customers have that LT95 'box:D I would definately say a turboed one would easily push that ratio in 5th. I must complain about my reverse though, that :mad::mad:LT95 has very high gearing backwards! I have to back up steep driveways in low range with the trailer on!!!

(PS, I may be in Perth in early sept, PM me some contact details if you like, we can catch up?)

JC

[isuzurover]

Hmmm, Do you think your 1st is too tall? I haven't driven any others with the 1.003's. All my customers have that LT95 'box:D I would definately say a turboed one would easily push that ratio in 5th. I must complain about my reverse though, that :mad::mad:LT95 has very high gearing backwards! I have to back up steep driveways in low range with the trailer on!!!

(PS, I may be in Perth in early sept, PM me some contact details if you like, we can catch up?)

JC

PM sent.

1st is OK, but I would prefer if it was slightly lower - more like the 4:1 in the LT95. For an NA engine, 5th seems a bit tall. But I agree, once I have a turbo I'm sure the gearing will be perfect. I wouldn't change it, because I like to have the engine just ticking over when driving along the highway.

[justinc]

PM sent.

1st is OK, but I would prefer if it was slightly lower - more like the 4:1 in the LT95. For an NA engine, 5th seems a bit tall. But I agree, once I have a turbo I'm sure the gearing will be perfect. I wouldn't change it, because I like to have the engine just ticking over when driving along the highway.

Ah ha...So what you're really trying to say is that you would like to drive my Turbod 4BD1 if we get up to perth, -only to check out the gearing of course....:cool:
Any quick tracks to do?:angel:

JC

[isuzurover]

Ah ha...So what you're really trying to say is that you would like to drive my Turbod 4BD1 if we get up to perth, -only to check out the gearing of course....:cool:
Any quick tracks to do?:angel:

JC

But you have an LT95 don't you? So I could only check the gearing on 1st, not 5th.... (better than nothing I guess :D ).

The powerlines track isn't very far away (fairly easy if it is dry though).

[justinc]

But you have an LT95 don't you? So I could only check the gearing on 1st, not 5th.... (better than nothing I guess :D ).

The powerlines track isn't very far away (fairly easy if it is dry though).

:oSprung! I was expecting you may forget all about gear ratio testing when you feel the raw torque in ALL gears....:D:D (I'm trying to hurry up your conversion to forced induction here, and you're splitting hairs (Or gears) about types of trans!!:D:D)
Powerlines sounds good , bring on the rain!!!!

JC

[isuzurover]

:oSprung! I was expecting you may forget all about gear ratio testing when you feel the raw torque in ALL gears....:D:D (I'm trying to hurry up your conversion to forced induction here, and you're splitting hairs (Or gears) about types of trans!!:D:D)
Powerlines sounds good , bring on the rain!!!!

JC

Believe me - the turbo is #1 on the list as soon as I finish the shed...

[mcrover]

Thanks folks, heaps of info in there and Tuasker, It will take me a few days to take all that in.