Put and overdrive on a 617 w/ 240 Four Speed
 

Hello all,

I will soon be removing the auto from my 1985 300D Turbo and trading it for a 4 speed from a 240.

I will have the new gearbox out on the bench and wanted to consider things I should do before installing it. A while back a pushbutton overdrive from a Volvo was proposed to be installed on a 240 manual but I don't know if it was feasible.

Does anyone have a clue about adding an overdrive? I know I probably won't need one with the 2.88 rear end but it would be nice if it wasn't too complicated.

Also, did anyone ever find the right pilot bearing for an 85?

Well I have a good, (very good) 1985 617 Turbo in my 240D. Love it! Would an OD be beneficial? Well, with the 2.88 gear in the rear end, I don't really miss an OD, though if I were on the interstate day after day, it might be useful. But an OD will complicate your project by quite a little and I would pass on it. Now concerning the pilot bearing, it is a bit tight. But I stuck it in my engine after putting it in the deep freeze overnight and installed it on a nice warm day - so it will go in. It has been working very good for two years now.

Another thing I have just realized, my 85 is from California and I don't know if that will change anything. I know there is some kind of difference between the Federal and California transmissions but I don't know what.

Also, do you expect it to effect my speedo or highway RPMs?

I wouldn't expect that you would transfer all that CA emissions over to a 240D. Well that is true. That is why you would install an OD right, to lower RPM's while maintaining speed. Of course, with a properly working OD, you will be able to go back to the original gearing by manually or electrically eliminating the OD. It would really be a lot easier to install say 15" wheels and tires, but then you loose flexibility. I think it is hard to beat the original Mercedes driveline set. If you are putting the 617 Turbo into a 240D car, make sure you put the speedometer and the differential from the 300D into it also, if you want the speedometer to read correctly.

I'm putting a 240 transmission in my california 300D. The California transmissions are slightly differen't and I don't think it will make a difference but I thought I would ask.

Will my rpms or speedo change just by doing the transmission swap?

They should be somewhat similar (I believe). If you want to get better highway RPMs I would swap in a taller rear (2.47?) and larger diameter tires.

And then have worse acceleration than a w115 200D with low compression and an automatic trans

Answer
 

This has been discussed in some depth.
http://www.peachparts.com/shopforum/diesel-discussion/334310-volvo-overdrive-splice.html#post3118060


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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.

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.;)

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.

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. :)