I think that the issue is the drive gearing may be the same, but the gear which drives the speedometer (in the tail of the tranny) varies to match the differential.
The EPC can answer this question... -Max -----Original Message----- From: mercedes-boun...@okiebenz.com [mailto:mercedes-boun...@okiebenz.com] On Behalf Of Rolf Sent: Thursday, June 03, 2010 10:38 AM To: Mercedes Discussion List Subject: Re: [MBZ] ISO a fix for lousy fuel economy in a W123 turbodiesel - with an incentive That is pretty much correct. The speedo is based on the rear diff not the trans. The automatics are all the same (for the w123) gearing and all the four speeds end in 1:1 gearing. The manuals differ from year to year based on engine and reivisions. -Rolf On 06/03/2010 10:35 AM, Mitch Haley wrote: > Jim Cathey wrote: > >> No, I correct myself. The speedometer is attempting to measure wheel >> RPM, but it's tapped at the tranny tailshaft. The 85 tranny is >> _expecting_ to have a lower tailshaft RPM for a given road speed, and >> so gears up the speedometer tap to make up for it. >> You put that tranny in a car with a shorter rear end, and the >> tailshaft RPM is higher than expected, and so is the speedometer >> output. > > I thought the MBZ way was to have the trannies all alike, and match > the speedometer head to the differential gearing. > > Mitch. > > _______________________________________ > http://www.okiebenz.com > For new and used parts go to www.okiebenz.com To search list archives > http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
