Ok this has started to make a whining noise for the past month. Ive sourced a second hand one that fits my diesel engine. they are hard to come by and all i could get was that it came from a 2l 6 speed manual model I ve seen alot about ratio's and is there any other way i can find out if its an exact match. there is no markings to the ratio? plus if i pay to get it fitted what will the outcomes be if it was from a 120d as opposed to a 118d?
bmw 1 series part 2006 118d rear diff
- Thread starter rexel2
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If original BMW specifications aren't available, I guess I'd be counting the teeth on both the pinion and crown wheel on both diffs if thats possible.
I think you need to get this correct really, as I think the speedo transmitter comes from the axle too, but not certain.
Its also possible to shim the clearances between the pinion and crown wheel, but its very specialised and I'm not sure if you want to go down that route.
John
I think you need to get this correct really, as I think the speedo transmitter comes from the axle too, but not certain.
Its also possible to shim the clearances between the pinion and crown wheel, but its very specialised and I'm not sure if you want to go down that route.
John
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I will assume yours is a 5 spd or maybe auto.
I would be careful, a 6 spd will probably have a completely different ratio. Old BMW diffs had a tag on the backplate telling you the ratio and if it was an LSD or not. For example my E30 M3 one has 3.25S on the tag denoting 3.25 ratio and the S for LSD. Whether new models still have this I don't know as I don't drive new cars.
Try looking on Realoem or bmwfans for the part numbers for your diff and the 2l one you bought.
I would be careful, a 6 spd will probably have a completely different ratio. Old BMW diffs had a tag on the backplate telling you the ratio and if it was an LSD or not. For example my E30 M3 one has 3.25S on the tag denoting 3.25 ratio and the S for LSD. Whether new models still have this I don't know as I don't drive new cars.
Try looking on Realoem or bmwfans for the part numbers for your diff and the 2l one you bought.
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You should be able to get some idea by jacking one wheel up and with it out of gear see how many revolutions the propshaft does to one of the wheel, if you halve that it should give you the ratio. It will need some careful measuring because it will contain a fraction of a turn and you need to measure this accurately.
Peter
Peter
this any good?
does show a tag on it, no idea if the ratio is on it
http://www.ebay.co.uk/itm/BMW-E87-1...d&hash=item1c2070e377&clk_rvr_id=529825094731
does show a tag on it, no idea if the ratio is on it
http://www.ebay.co.uk/itm/BMW-E87-1...d&hash=item1c2070e377&clk_rvr_id=529825094731
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Ratios filed under transmission
http://www.bmw.com/com/en/newvehicles/1series/3door/2007/_shared/pdf/1series_datasheet.pdf
As you can see the diff ratio changes depending on the ratio in 5th and 6th gear and engine size. 2.79:1 for example means the input will turn 2,79 times for every one turn on the wheels. So the closer you get to 1:1 the higher the ratio.
Seem to remember that the older ones were 3 stud and the newer ones were 4 stud, so worth a visual check as well
http://www.bmw.com/com/en/newvehicles/1series/3door/2007/_shared/pdf/1series_datasheet.pdf
As you can see the diff ratio changes depending on the ratio in 5th and 6th gear and engine size. 2.79:1 for example means the input will turn 2,79 times for every one turn on the wheels. So the closer you get to 1:1 the higher the ratio.
Seem to remember that the older ones were 3 stud and the newer ones were 4 stud, so worth a visual check as well
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