Volvo 5 speed manual into Mercedes??
 

G'mornin',

A friend of mine has a 5 speed manual transmission in an '88 Volvo 240DC.

I wonder who manufactured it.....ZF maybe?? I also wonder if it will bolt up to a Benz??

I can get it really cheap.....maybe even free.....thought dawned on me that just maybe it's an "off the shelf" tranny, and if so....do we have another source for the elusive 5 speed??

SB

i have pondered that question myself. bmw trannys too. but i dont know the answer.

i think it is possible.

tom w

Not to change the subject but while we're having trans talk, What about this thought...
I wouldn't change one thing on the engine of my 300d. However the car was designed to travel at 55mph not today's highway speeds of 80 in some states. The MPG would be better and get the RPMs down if it had a modern transmission. Anyone put an Overdrive Tranny in a w123? Mines great! Just doesn't shift into 5th gear like I wish it could.
While you're changing the trans maybe the thought of updating? I don't know but I do know if mine went I'd really be doing a search on it.

"However the car was designed to travel at 55mph not today's highway speeds of 80"

I seriously doubt the validity of your statement. I can only speak from my long ago experience with a '79 300 CD. That car would run 90 all day long, but the rpms were rather high. I think the gear ratios were designed correctly by the factory.



Steve

several folks here have swapped in the 247 diff from the v8 equipped cars. it is like having an overdrive tranny without first gear. there is some sacrifice in acceleration but the highway rpm is down and fuel economy is up. it can result in from ten to twenty percent better economy depending on who's experience you listen to. engine wear and noise is greatly reduced as well.

tom w

I agree with you. Many rear differential swaps have been performed with the idea of better highway performance due to lower RPM's. 3.08's swapped for 2.88's and 2.47's. The results have always seemed worth it to the owners despite claims of "lugging" the engine or reduced performance at lower speeds.

The arguement is made that these are high-speed diesels. Yes, they are in a relative way. The reality is the torque curve is pretty flat so changing gearing modestly has no noticeable effect on performance but helps drastically at cruise speeds by lowering RPM.

I have read a bunch of literature and seen it said time and again that a diesel engine should be geared to spin at its torque peak while cruising. That last time I checked that peak occured at 3100-3200rpm on the 617. Sure you can spin the engine faster with no ill-effects but why would you if there are alternatives?

Look into the Volvo 5speed. It would be nice to find a bolt on manual that is not so rare as the MB trans. If I had the money I would be trying to get a Borg Warner T5 or Tremec to bolt up. The B&W is so common in 5.0 Mustangs and a very nice shifting trans. I would imagine that a modified MB bellhousing, custom clutch/flywheel/input shaft would be required. The domestic performance clutch suppliers can do this stuff but its not cheap. Unfortunately.

RT

I think he means the 2.47 differential.....
 

I think you mean the 2.47 axle ratio differential......not the engine.....

SB

Isn't that what MB intended in '85??
 

From your sig, you own an '84 300D......

All MB 300D's are not created equally......my car, along with all other USA model '85 300d's are equipped with the 2.88 axle ratio...

'83 and '84 300D's come with the 3.07 axle ratio....W123.133 cars

'82 and older 300D's come with the 3.46 axle ratio......W123.130 cars

I had thought that this was the MB reaction to increasing highway speeds here in the USA......

SB

Note: I also think that I would get better highway mileage if I could run around 85 mph on a steady basis....due to the rpm/torque band and 2.88 gears....

I'm just curious, are the gear/tranny ratios different in Euro spec cars? I would think that the ratios and gears were chosen for US spec cars based on the 55mph speed limit, fuel economy situation, etc. in place in the US at the time our cars were sold. That is the car was designed to run at X RPMs all day long, how fast X RPMs would be wound depend on the gearing and tranny.

While I have no doubt that I could cruise all day at 75-80 or more, an overdrive (or 5th gear on standards) would help economy greatly while maintain the off-the-line "performance".

3000 Rpm = 70 Mph
 

My ' 85 turns about 3000 RPM at 70 MPH, which is a nice cruising speed for that car. I believe the '85 has a slightly taller rear end, don't know the numbers. The 123 body is not that slippery and fuel economy really goes down if I push too hard against the air resistance. My wife's '87 is another matter. The 124 body has a great Cd and the big six is so smooooth at highway speeds...

Actually the 82s are W123.133, with 3.07.

Not likely, your mileage will decrease at higher speeds regardless of ratio in these cars. The increased power requirement will overcome the higher efficiency of operating at the peak torque point.

At the yard I frequent, there is a w123 that was manufactured 10/84 So that would make it the 85 model. If I were to stick that rear in my 83, what kind of top end speed would I be seeing @ 3200rpm. Is the switch worth it?

I swear by the 2.88 rearend in the 85's, because at 70mph I'm turning 0 rpm's......:o :o

[QUOTE=Jeremy5848;1401593]My ' 85 turns about 3000 RPM at 70 MPH, which is a nice cruising speed for that car. I believe the '85 has a slightly taller rear end, don't know the numbers.QUOTE

You are correct sir! My '84 300D turns @3400rpm at 70-75mph, IIRC. I have in my posession a 2.88 diff and cluster from an '85. My math says I should see approximately 400rpm less at the same speed once I swap. That with a slightly taller tire will allow more comfortable cruising in todays 75+mph traffic.

RT

I still like my 3.07 gears with 205/70-14 tires, that gives me a tad over 3500 rpm at 80 mph. I could lower the rpms a little with a 2.88, but I don't want to lose any more low end power. My engine seems happiest between 3000 and 3500.