Question for 2.47:1 Axle Users:
 

For thos of you who have used the 2.47:1 axle behind a 617, how did the swap affect your part-throttle/full-throttle upshifts????

I am gathering parts for this swap, sp your input would be appreciated....Robert

where can you find one?according to my book by NITSKE there are no w123 models with that rear end gear.the only model i can think of with that gearing is a w126 body.Wouldnt you need modification to make that work.I am thinking about putting a taller gear in a 240,like a 3.07 from another w123.unless i can find a five speed for around the same price...but i think the former will happen first.I recently got less than 22mpg on a three hundred plus mile round trip.About nintey percent of the milage was on the highway.I was doing between 70-75 on the highway.Still that is only a mile or two more per gallon more than a 12 valve cummins powered ram i used to get 20 on the highway with.i dont mind being a little slower either.if i am not in a hurry i will put on the ipod ,listen to my podcasts(not music,yes really)and watch the gluttons pass me by at like i am standing still at 59mph.all while getting 5-10 mpg more than them and taking only a third or a quarter more time to travel the same distance.

dont know how it will effect an automatic, I have a 2.47 and 4spd in my coupe. It is initially slow off the line but not so much to be annoying. once I build up a little speed the turbo kicks in and I can keep it in first a little longer since it is now effectively geared to be where second was. Basically its like I have a 5speed and I start out in second. I have been very happy with it in all situations. I have driven from FLA to OH a couple times and it handles the mountains on the highway and the hilly Cincinnati area surface roads with little issue. You have to be just a little more conscious of roll back when stopped on a hill, but thats with my stick.

the rear is out of a first gen 126 gasser, you will have to change the pinion to the diesel w123 sized one and flip the orientation of the rear mount but otherwise it bolts in.

That is awesome,you must get better milage than my 240 around town if you drive for decreased fuel consumption!what is your rpm at 70,60 and 50 in the 4th gear?

i used to drive a five speed gasser saturn.i was getting about 25 mpg around town.That was shifting at 2k and coasting to the stoplight.i am looking at doing a 3.07 swap and a 4speed conversion or just buying a model with one in a 240D.i am thinking i can get 30mpg around town from a 240D if i shift the same way.Perhaps a 2500k shift point may work too.

You need to find the diff from a V8 gasser in the years from '81-'85. I found one from a 500 SEL for the W126, although I never installed it. It's a direct fit for the W123, although the yoke needs to be changed because the gasser has a larger driveshaft.

can a yoke change be done with common hand tools?what all is involved in doing this swap?

Brian,
Driveshaft size.

81-85

Is the 126 and 123 diesel the same size?
is the 126 gasser thicker?

It really made no difference in the shifting aside from the tranny holding each gear about 15-20% longer in normal driving.

There is a special socket for the pinion nut.

The torque on the pinion nut is somewhat critical.

The gasser uses a larger yoke, presumably for the additional torque. I'd suspect that the tube diameter might be slightly larger as well, but I really cannot confirm it.

best I can recall 55mph is around 2000RPM, 85mph is around 3000RPM

Saraswatch, If you go to a 3:07 Differential in a 240D, you just might be gearing it up too high. the stock 240D diff is 3:69, and the horse power of the engine is 67HP.

There is the 3:46 from the 300D none turbo.

I installed a 3:58 from a grey mkt car in our 240. this change is 3% & I do see a change in speed when I hit the hills. It drops off sooner.

If you do change the Differential, then get the Speedometer from that vehicle. the spedo is geared to the Diff.

Charlie

Pinion seal friction preload
 

This is very true. the friction preload must be determined, before the pinion nut is removed. then when replacing the nut, the friction preload must be the same.

this thread will explain it.


www.peachparts.com/shopforum/showthread.php?t=233540

Charlie

I live in Fl,so i dont see to many steep grades......if i cant stand i will change it back...but i can handle accelerating at the half rate of other drivers,they are the ones that seem like they cannot.



will everything hook up froom a 300d speedo to the 240?(except for the tachometer of course)
i wonder if a tach could be made to work from parts off a 123....
i recall seeing some video of a 240D with a tach on it...probaly uses very similar parts such as cable and magnetic pickup near the crakshaft pulley.

oops, forgot to mention, you will need to get good at math in your head. I have to multiply my speedo reading by 140%.