Rovers North High Ratio Transfer

[jumpmaster54]

I am finishing my 109 restore and I was thinking of an overdrive. I have a Konig winch on the front and if I go with a Fairey OD then I lose the winch option. Ig I go with the Rovers North High Ratio Transfer I can get both.

Does anyone have one of these high ratio transfers mounted? Does it give the top end as an OD? Please assist with any info.

Thanks

Stan

[I Leak Oil]

I don't hava HR transfer case but do have an OD. The ratios are about the same and I know I don't like driving around with the OD engaged unless it's on the highway. Too much of a dog(even more than usual!). My truck is an 88" with a 2.25 gasser.

[Cutter]

I have the HR TC on my 109, but I have a 6 cylinder. From my discussions, the always on nature of the High Ratio is a bit much for the 2.25 like I Leak Oil suggests. On mine it is great, and if you had a re-power I think it is a good alternative to an OD.

[Les Parker]

:)Please note if you fit the High Ratio Trans. box, the PTO option is gone !
The out put gear is changed from the standard one to a larger one, so PTO clutches CANNOT be fitted to the transfer box.
I hope your winch is crankshaft driven so you can opt for the High Ratio T. Box option.

[jumpmaster54]

My winch has the shaft that goes to the transfer. I guess I could always sell the winch on here. Its a Konig period winch and everything works. What is a fair price?

Stan

[leafsprung]

Les, The ashcroft HR t case can be used with PTO accessories (except overdrive) . . . The ashcroft output gear (which is larger) does in fact have the PTO drive teeth.

-Ike

[willincalgary]

I have an 88" with a very fresh 2.25 and a Roverdrive. No trouble driving around in overdrive all the time. It is a bit slow off the line but not that bad. I suspect with a 109 the highway might be a bit frustrating with just the high ratio.

[TeriAnn]

The Engineers at Land Rover did a pretty good job of matching the gearing of a Series truck to the four cylinder engine so it can do the best job of pushing the truck under most conditions. When the early seventies gas crunch happened the overdrive came along adding gears allowing you to better be able to pick a gear that provides the best fuel economy. More often than not the best fuel economy was found by splitting the standard gears and not 4 over. The engine can not handle 4 over well in any adverse conditions. Especially with the heavier 109.

Stock form you have an effective overall gear ratio of 5.4:1. The transfercase high range is a 1.15:1 underdrive. Coupled to the stock 4.7:1 R&P you get 65 MPH @3686 RPM with 32 inch dia tyres.

Add a Fariy overdrive with its 0.78:1 high range to the stock gear ratio and you have an effective overall gear ratio of 4.2:1. You will reach 65 MPH @ 2867 RPM with 32 inch dia tyres. Assuming road conditions allow your engine to push that gear that fast.

Add a Roverdrive with its 0.8:1 high range to the stock gear ratio and you have an effective overall gear ratio of 4.32:1 You will reach 65 MPH @ 2948 RPM with 32 inch dia tyres

An Ashcroft high ratio kit converts your transfercase from a 1.15:1 underdrive to a 0.87:1 overdrive. changing the overall top gear ratio to 4.1:1 You will reach 65 MPH @ 2798 RPM with 32 inch dia tyres.

A stock transfercase with 3.54:1 R&P gives you an overall top gear ratio of 4.0:1. You will reach 65 MPH @ 2740 RPM

The higher the overall ratio the harder your engine has to work to push the gear. With a heavy 109 you may be at full throttle pushing the gear to 65 or with minor adversity you might not be able to push it that fast.

The big advantage of an overdrive is that you can split gears to find one that you engine can easily push without strain and with best fuel mileage. And the overdrives have a slightly lower ratio allowing your engine to push them easier.

The Ashcroft conversion and 3.54:1 R&P is like being stuck in a taller overdrive all the time. OK, in high range only with the Ashcroft and in all gears with the coiler R&P gears. The 2.25L engine has a real tough time pushing those ratios.

When you look at the numbers I think you will conclude that you are better off pairing an overdrive with a 2.25l engine. If the engine can't handle 4 overdrive where you are driving you can always take it out of overdrive. You can't do that with an Ashcroft conversion of a coiler R&P gear set.

Where the Ashcroft conversion shines is when you couple the transfercase with a more powerful engine. I have a Ford 5.0L V8 on my SII coupled with the Ashcroft converted transfercase and love the combination. But I would have hated it when I had a 2.25L engine.

[jumpmaster54]

TeriAnn,

I have thje 109 with the 2.6. Does this changes anything as far as the HR transfer. Is the one that Rovers North sells an Ashcroft?

Can a PTO be used with an overdrive such as roverdrive or the HR transfer like ike said? Les says NO.

Thanks

Stan

[Firemanshort]

Not for nothing.... everything Teri Ann said plus the H/R gear set will be quieter than the overdrive. I realise that "quieter" is all relative, but neverhteless......

I had an O/D in my Stage One. Then I ditched that (well, it ditched me) and I swapped transfer gears to a higher set. I am VERY HAPPY with the quieter gear set - but I have a freshly rebuilt 3.5 V8 with a slightly taller cam in it.

[leafsprung]

Stan,
To clarify: The high ratio case is compatible with the PTO winches and other PTO accessories but you cannot use a HR case with overdrive. Nor can you use a overdrive with a PTO (except the rarer bottom PTO).


-Ike

[Cutter]

TeriAnn,

I have thje 109 with the 2.6. Does this changes anything as far as the HR transfer. Is the one that Rovers North sells an Ashcroft?

Can a PTO be used with an overdrive such as roverdrive or the HR transfer like ike said? Les says NO.

Thanks

Stan

The HR transfer works well in the 2.6, at least in mine it does. The engine loses grunt in 4th but gets comfortably up to 55-60 cruising. FYI though mine is a euro 2.6 which different than the NADA. TeriAnn has a good breakdown of this on her site.

[leafsprung]

Les asked me to post a couple pics to help you guys out with your decision making process. The first one shows the stock output gear (small) the HR t-case gear (large) and the PTO clutch dog. The second shows the PTO clutch dog engaged with the splines on the HR tcase gear. For what its worth I run the HR tcase in three of my trucks (one with a PTO winch) and they are great solution to gearing.

[TeriAnn]

Not for nothing.... everything Teri Ann said plus the H/R gear set will be quieter I swapped transfer gears to a higher set. I am VERY HAPPY with the quieter gear set - but I have a freshly rebuilt 3.5 V8 with a slightly taller cam in it.

With a 3.5 V8 I'd be very surprised if you were not happy with an Ashcroft high ratio transfercase conversion.

Not knowing the weight of the 109 in question, were or how you drive I can only make a guess. Unless you live and drive on the flats near sea level and are OK with what would sympathetically be called gentle acceleration rates for a Series truck, I suggest a high ratio transfercase would not be the best of solutions for a 109.

The Euro six does have about 11 more lbft of torque and 20 additional HP than the 2.25L engine. It might be enough to make the difference, depending upon where you drive and how often you encounter mountains. It is iffy in my estimation but better than the 2.25L in a 109.

What you might do is temporarily pop in a pair of Disco I or RR Classic diffs from a wrecking yard and see how you feel about the driveability in high range. 3.54 diffs & a high ratio transfercase have close to the same overall fourth gear high range ratio. It is a cheapish way to find out if you can live with a high ratio kit without putting out the big bucks. When you are finished testing you can sell the coiler diffs.

If the coiler diff ratio works for you then a high ratio transfercase will work as well and you will get your low range back.

You will have to ask RN what brand they are selling. I would guess Ashcroft Transmissions but you never can be 100% sure unless you ask.

[greenmeanie]

With a 3.5 V8 I'd be very surprised if you were not happy with an Ashcroft high ratio transfercase conversion.



Fireman has a Stage 1 with a LT95 which has the advantage of strength and a wide range of ratios available for conversion. .9962 is the highest ratio

[jumpmaster54]

So with my NADA 109 IIA with the 2.6 petrol can I use the Rovers North High Ratio Transfer and my Koenig period front winch together?

Alot of info given and a few comflicting? Please advise before i spent alot of money and find out it does not work. Thanks

Stan

[73series88]

im not sure about the 2.6 in a 109.
ive got a 2.25 in an 88.
i was told i could put range rover diffs in my axles.
and it would but the equivelent to having an over drive permanately engaged. well i eventually got a fairey od and ive left it engaged and thought there was something wrong with the truck. no power. duh!!!!!

bigger truck bigger motor might equal same power loss in perminate high gear.

i use my od as a fifth gear basically and its great.
maybe im just talking out my ass.
aaron

[Cutter]

So with my NADA 109 IIA with the 2.6 petrol can I use the Rovers North High Ratio Transfer and my Koenig period front winch together?

Alot of info given and a few comflicting? Please advise before i spent alot of money and find out it does not work. Thanks

Stan

The NADA 2.6 head is setup for highway driving, so it has more power up high. The Euro has the power more in the lower range, so the HR Transfer is a better fit. Not sure if it is worth it, I also live at sea level in a pretty flat area, so like Terriann was saying, if you are in a hilly area it might be asking a lot of the engine. I would say the 2.6 is still underpowered for a 109, regardless of transfer case.

[Les Parker]

Stan,

Yes, with the high ratio t. box on your standard Series gearbox and you will be able to use the Rear PTO.

Thanks, Ike for posting the various pix for the different options for the rear out put gear.

[jumpmaster54]

But can I use the fron PTO for the winch?

Stan

[leafsprung]

yes

[Lord Icon]

The front pto comes from the drive dog on the crank pully . It should have nothing to do with the trans .

[leafsprung]

I think he means the forward facing rear PTO as used on PTO koenig winches. Most front PTO winches are driven from the back of the transfer case, the exceptions being the turner, koenig crank driven and capstans.

[jumpmaster54]

OK well I'll post a few photos and then need help so I dont make a costly mistake.

Stan

[leafsprung]

if it works with your current transfer case it will work with the HR case unless its an overdrive. :thumb-up:

[jumpmaster54]

OK thanks, thats all I was trying to verify. I have it hooked up to a normnal transfer and want to install the HR transfer and keep the winch. Awesome.

Stan

[73series88]

whoooo!
glad we got that worked out.
aaron