Rear diff ratio
- Thread starter w sharp
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neilly
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what vehicle do you have and have you got a photo?
Cheers
Cheers
300bhp/ton
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Probably a 3.54:1 which is the standard diff used in the Range Rover classic, Discovery 1 and all Defenders (90/110).
Most of these have the filler on the axle, however very early Range Rover's and most/all Series axles have the filler on the diff. Hence you loose it if swapped for a latter diff.
Stock Series diff is 4.75:1, if you know your tyre size/speed in gear or rpm. Then you should be able to use an rpm calculator to confirm what diffs you have.
https://www.ashcroft-transmissions.co.uk/calc/ratio_calc.html
If it is a Series you are running with the stock gearbox (transmission), then you'll fine it'll top out around 60-65mph and be revving high. You'll also be able to pull 4th gear below 30mph. With 3.54 diffs there will be a large gap between 3rd and 4th gear and it will likely not want to pull 4th below 30mph, but should allow comfortable running at 65mph.
Most of these have the filler on the axle, however very early Range Rover's and most/all Series axles have the filler on the diff. Hence you loose it if swapped for a latter diff.
Stock Series diff is 4.75:1, if you know your tyre size/speed in gear or rpm. Then you should be able to use an rpm calculator to confirm what diffs you have.
https://www.ashcroft-transmissions.co.uk/calc/ratio_calc.html
If it is a Series you are running with the stock gearbox (transmission), then you'll fine it'll top out around 60-65mph and be revving high. You'll also be able to pull 4th gear below 30mph. With 3.54 diffs there will be a large gap between 3rd and 4th gear and it will likely not want to pull 4th below 30mph, but should allow comfortable running at 65mph.
Yes it’s a 1973 series 3... but as I understand it the rear diff is not original, as no filler hole on it any where.... runs top speed 55 (going down hill ) but slow to build up speed In 4 gear, usually shift into 4th about 35 mph or so, also in the shop currently getting front pinion looked at, as bearings fell out while changing fluids for first time
, but will also have a compression test done on the 4 cylinder diesel Perkins that powers it
, but will also have a compression test done on the 4 cylinder diesel Perkins that powers it
300bhp/ton
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ok, year the Perkins are good old unit, but not really speed monsters, was assuming you had the 2.25 petrol/gas motor. I'd be willing to wager it has 3.54:1 diffs in it, at least in the rear. Have you used it in 4wd? As obviously the front diff would need to match the rear, but I've seen cases where it hasn't been changed!
Thanks, I believe it to be a 4.203, but diesel, and I’ll have to check the diffs to see if they match..... I think the previous owners had their way with it.... still trying to figure it out, but lots of torque just not much speed... which I’m ok with (maybe a turbo kit in the future?)
