Put and overdrive on a 617 w/ 240 Four Speed - PeachParts Mercedes-Benz Forum

Science and Energy · #1 03-22-2013, 09:09 AM

Quote:

Originally Posted by junqueyardjim

There is no difference in the manual transmission and I doubt if there is any difference on the automatic. No, your RPMs are controlled by the throttle - the more you step on it, the more RPMs increase. If you don't change the differential your speed will be the same as before, except that the automatic has some "slip" in the torque converter. But basically, you will produce the same speed as with the automatic at the same RPM, except for the "slip".

Sorry, I ment highway RPMs.
OK, then my speedo might read slighlty low (slip). Thanks, that is what I was looking for.

t walgamuth · #2 03-22-2013, 09:56 AM

Your speedo will read the same as its driven off the rear of the tranny. For a given speed with the same gear ratio in the rear you will see a little higher rpm on the automatic because of the slip. So a little more engine noise for the same speed perhaps. I estimate the slip might be about 200 rpm for a given speed.

vstech · #3 03-22-2013, 10:14 AM

Quote:

Originally Posted by Science and Energy

Sorry, I ment highway RPMs.
OK, then my speedo might read slighlty low (slip). Thanks, that is what I was looking for.

No. your speedo will read exactly the same no matter what transmission you use.

only the engine RPM will change for the speed indicated with transmission gearing/manual/TC slippage.

now, if you change the Differential, or tire diameter then the speedo would be off the percentage of change.

Science and Energy · #4 03-22-2013, 10:41 AM

Thank you both. I didn't realize it was measured at the final point after gearing but duh, that makes sense now that I think about it.