DIFFS
some time ago i looked in to changing the gearing on my G with the help of gav for raitio info
and from time to time people bring this up
looking at old emails
maybe of some interest to you HOT ROD G owners
i am trying to change the gearing on my G
VIN46033327065280
4.86 i have std already, on the calculator 3940rpm 29" 70mph
and i whould like to change front & rear diffs (crown & pinion)
for lower RPM to aprox
4.38 is lower still on the calculator 3550rpm 29" 70mph
do you have any (used) (reconditiond) in stock
(NEW)
GEAR SET 35.8
RING GEAR
DRIVE PINION
you would be looking at about 1150 euro per axle
That would be 2300 euro just for for the parts to reduce the revs by only 400rpm at 70mph.
I am sure there is a calculation to see what the fuel saving would be but I don't think it would be very much. It would probably be cheaper to just fit larger profile tyres.
I've looked into this at length, Here is a calculator to work out what difference your changes will make, tyres alone doesn't really do it.
Gordon
http://www.pxwheels.com/gearingcalc.xls You'll need ms excell on a pc to use it
I like your spreadsheet Gordon, just shows what a mine field this is!
I put slightly over size tyres on mine which helped on road, around 3.4k rev's at 70mph but this IMHO had a detrimental affect in that low range first is now too high (yes I know that's the wrong way to express it but you know what I mean).
Anyway if I just want to get somewhere I take the car if I it's more about the journey I take the G Wagen and I'm quite happy trundling along at 60mph'ish.
Who knows how fast it would go, it feels like it would pull 5.5k in top, but for how long!? and I'm still tinkering with respect he IP.
I've been pondering a 6 speed swap but I don't think that 6th is an actual overdrive? If so what's the point.
Six speed boxes do have an overdrive top gear an a low first gear, so with higher diffs everything ends up the right ratio, don't forget the crownwheels on a 460 are different sizes front and rear, and a huge job to change.
you would get a match set
the overdrive was mounted on the (separate unit) switch on the dash) frame but you have to weld and cut / change the prop shaft
i think fitting a 6 speed A/T to my W460 617a would not be a walk in the park
Just some thoughts from experience on something else.
When I had a Land Rover, in order to fit larger off road tyres, I changed the front and rear diff crown+pinions. The smaller 4-cylinder diesels just didn't have enough torque. This was mechanically a relatively easy job. However, it was also necessary to fit strengthened half shafts and a double yoke propshaft in the front to get the set-up correct. All in all, it was an expensive exercise which I would never do again simply because once you change one part of a driveline, everything else will always be affected and I think you will lose reliability (I also had to change a gearbox after about 25000miles.........but this could just be a Land Rover thing as the gearboxes are a known weakness, albeit relatively cheap to replace).
For 'serious' offroading I have since bought a Pinzgauer and am completely happy with keeping the driveline totally stock (as is the driveline on my G as well). For the sake of a few mphs or mpgs, I'd rather spend a little more time on the road than spending all the hard-earned cash again.I have found that soundproofing is a much better (and cheaper!) alternative to making journeys more pleasant.
Hope that helps,
Ph
ph
i am with you there 100%
reliability is the key
my last drive in my G was 925 miles (200 lts diesel) in one day
left graz 6am arrived eastboune 3am 21hr non stop bar 1hr on the ferry
not bad for 27 year old G
temp never went over a tad over the 1st quarter mark
adrian
Don't really think you can compare landrover drivetrain to anything under a G
Ah OK. I won't be getting into changing the diff's but if the getrag dies its an option
Six speed boxes do have an overdrive top gear an a low first gear, so with higher diffs everything ends up the right ratio, don't forget the crownwheels on a 460 are different sizes front and rear, and a huge job to change.
russ before you take the plunge look in to these good all rounder
russ before you take the plunge look in to these good all rounder
Nice! But maybe a little extreme / big for us.
The Man is the biggest truck I'd go for. Or maybe a 416 series MB van.
Unimog's fall into the sledgehammer to crack a nut as well.
As I say, decisions.......
just in case i can pull this off any one interested
4.4's to 1 . diffs
Hi Adrian
Is 4.35:1 worth doing? I'm sure your G would pull 37/9s which comes out at 4.11:1
I have these in mine and I'm considering going higher to 3.72:1
Gordon
G i can get these or at least they offered to me
GEAR SET 35.8 pn 6023502539
RING GEAR pn 9013530212
DRIVE PINION pn 9103530410
ps
i cant open your link and i am a bit thick to work it out if i could
what rpm would the 3.58 give me at 70mph ?
thanks adrian
STD
VIN46033327065280
4.86 3940rpm 29" 70mph (std)
-------------------------------------------------------------------------------------------------------------
NORWAY 4.38 3550rpm 29" 70mph (ideal 617a)
------------------------------------------------------------------------------------------------------------------
S-TEC offer GEAR SET 3.58 ?????rpm 29 70mph (ideal 606a)
----------------------------------------------------------------------------------------------------------------------
If your doing 70mph and 3940 with 4.86 on board, just by changing to down to 3.58 would reduce the rpm down to 2902 (decimals) at the same speed. A substantial 26%.
I'm getting 70mph at 2800 rpm, but I'm getting a bit of OD due to 6 sp manual box.
With the old 4.8 and standard 5 speed box I was getting 62 mph at 3000 rpm.this would've been about 3,400 rpm for 70 mpg. Presumably down to a small amount of OD in 5th. For me, the engine was working tar too hard at this speed...
The 4.1 (and 6 speed box) has made a huge difference to driving on fast roads, and the lower 1st and 2nd gearing is pleasant driving around locally. It's a good combination...
The downside - the previous "flattery", where road speed is 54 but speedo reading 60 has now changed to road speed 69, but speed reading 60 could be a bit of a problem. I need to locate a good technical instrument adjuster...
My figures above are for my vehicle. My calculations of what you might expect for you proposed change are mathematical comparisons and a just a guide.
A further downside I should mention, with the lower gearing, my G is rather less enthusiastic about lengthy up hills climbs. A fairly steep hill on the way back from Somerset had me knocking down to 4th - a bit embarrassing... So, next on the list for me - more horses...
As mentioned further up this post. This is not a cheap undertaking. It will coincidentally save on fuel - but really - just a pleasant additional benefit. In my case, this exercise was undertaken for a slightly better "traveling" speed on faster roads without killing the engine.
big thanks for that geoff
i have been offered a set of EX works so its more labor is the issue
thanks again adrian
Adrian 35.8 refers to the teeth on the gears not the ratio, that would be 35 divided by 8 = 4.375
Mine has 37.9 = 4.11 with a six speed box and 265 75 16 BFG ATs gives me 29 MPH for every 1000 rpm
so 70 MPH is 2414 RPM
Oops! My bad. I read 35.8 as 3.58.
My setup is 4.11 also with 6 speed manual. But I'm getting just 25mph per 1,000 rpm. That said - I'm well pleased with it - over the previous speed vs. rpm.
I knew there was a 3.xx ratio "out there" somewhere. But - "technical "is a language I struggle with...
Just as a by the bye, much lower than 4.11 would further diminish the "getting up a hill" ability, which is the only issue I have. As previously, a few more horses ought to sort that - at some point.
Sorry Adrian. A lot of writing on a misread post... That said - 4.11 works really well...
Oops! My bad. I read 35.8 as 3.58.
My setup is 4.11 also with 6 speed manual. But I'm getting just 25mph per 1,000 rpm. That said - I'm well pleased with it - over the previous speed vs. rpm.
I knew there was a 3.xx ratio "out there" somewhere. But - "technical "is a language I struggle with...
Just as a by the bye, much lower than 4.11 would further diminish the "getting up a hill" ability, which is the only issue I have. As previously, a few more horses ought to sort that - at some point.
Sorry Adrian. A lot of writing on a misread post... That said - 4.11 works really well...
What engine is in your G? I haven't manage to track down a 3.72 gearset for a 460, 463 is more straightforward
Started life as a 280GE, Now a 5 pot Musso. I'm not technically savvy enough to recount the three numbers that others identify their engines by. It's a SWB, so I've decided it's now a 290 GDS...
Did I mention - I'm not very "technical"...
Adrian 35.8 refers to the teeth on the gears not the ratio, that would be 35 divided by 8 = 4.375
Mine has 37.9 = 4.11 with a six speed box and 265 75 16 BFG ATs gives me 29 MPH for every 1000 rpm
so 70 MPH is 2414 RPM
thanks Gord
every one seems to use different numbers for the same thing no wonder
its confusing
adrian
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all size gear ratio these were just what me and gav were looking at
i did,nt do it 2, reasons if i was,nt happy big work to change back
and the compromise road / off road
and after ruling this out then i went on to look into the overdrive system
had a go in a G with one fitted on a M/T gear box (really cool )
after talking to the guy it was possible but as my G is A/T
not a easy job and made the diffs seem cheap