incorrect gear ratio plzzz help
 

hello pppl i have a 04 E500 i replaced the rear sub frame with the diff and the axles i got it used from a different E500 i dont know the year tho...now im getting a check engine light with a p0730 incorrect gear ratio and the car wont shift from 1st gear... so im wondering if the diff would make a difference or the axles.... thank you in advance....

My guess....it is a different ratio than you had and it's throwing off the speed sensing system...kind of like putting different sized rims front and back. Rotational speeds of all wheels and drive shaft are checked for anomalies that would show skidding, wheel spin, etc. I'm also guessing someone with StarDiag and some knowledge can code the car to match the ratio. I don't know if you can do this to any degree of accuracy but turn the drive shaft by hand and count the revolutions of an axle to get the ratio. Or better, remove the back plate of the differential and count the ring and pinion teeth (I've never done it on a MB but it should be possible).

thank you very much for the reply.. i have the car at the shop right now and im waiting for them to see whats going on with it..