diff swap
07-17-2022, 01:36 AM
#1
Newbie
Thread Starter
diff swap
I'm thinking of putting the differential from a 300td (not sure of year but w123 chassis) in my 81 240d w123 with a manual trans. I'm considering this because I have the 300td one already and don't want to buy a 240d one if I can avoid it.I know the gearing is different and I'm wondering how it would affect driving the cat Any advice? Thanks. I almost forgot . I'm doing this because I messed up the output bearing in the side of the diff. How hard is it to replace that bearing?
Last edited by noswendel; 07-17-2022 at 02:09 AM. Reason: after thought
07-17-2022, 06:03 AM
#2
MBWorld Fanatic!
If replacement Dif has:
Higher ratio = Say Old is 2:1 and new is 3:1 - Quicker off line from stop, less top end speed, for same speeds engine RPM will be more then before, tend to get worse mpg and speedo read incorrect (I forget where connected on Car Axle or Tranny)
Lower ratio = Old is 3:1 and new is say 2:1 - opposite of above.
It is like changing tire OD from one OD to larger or Smaller OD.
you are changing the amount of engine driveshaft RPMS to Tire RPM raio.
As to replaceming bearing if yo uhave never serviced a Differential best to leave to pros as many measurements and shimming required to ensure proper bearing preloads and gear meshing.
Higher ratio = Say Old is 2:1 and new is 3:1 - Quicker off line from stop, less top end speed, for same speeds engine RPM will be more then before, tend to get worse mpg and speedo read incorrect (I forget where connected on Car Axle or Tranny)
Lower ratio = Old is 3:1 and new is say 2:1 - opposite of above.
It is like changing tire OD from one OD to larger or Smaller OD.
you are changing the amount of engine driveshaft RPMS to Tire RPM raio.
As to replaceming bearing if yo uhave never serviced a Differential best to leave to pros as many measurements and shimming required to ensure proper bearing preloads and gear meshing.
