Drivetrain Slack - 240D Manual

[jpmaynard]

Hey there folks. Well, being fully in love with my 81 manual EVERYTHING 240D as i am, I've been doing everything in my budget to bring it back to its former glory. Ive been trying to reduce the "rubber band" effect when you let off the accelerator, decelerate suddenly or miss a shift into second, etc. I've replaced both engine mounts, the transmission mount, the driveshaft center bearing and the front flex disk. Although its tightened it up considerably, I still have an annoying (atleast to me) amount of rubbery feeling in the driveline somewhere. When i changed the front flex disc and driveshaft bearing the back flex disk looked fine. oh yeah, new timing chain about 5k ago.

what next? rear diff? the driveshafts?

any insight will be welcomed. thanks.

[PatrickW]

Any noises associated with this?

- Patrick

[R Leo]

I think they came that way from the factory. My manual w115 will give you whiplash if your attention flags for a moment when starting off in 1st gear. Try staring off in 2nd on level ground.

[jpmaynard]

no noises associated.

[t walgamuth]

i think that you are experiencing a normal thing, perhaps. the gas engine mb's have only one rubber donut at the tranny. diesels have one at the diff too. this is because of the massive explosions that the diesel has, making lots more vibration than a gas engine. unless you have a bad donut in the back the only other place in a stick car for this is the springs in the clutch disc and they dont allow all that much movement. i am guessing you are looking for the direct feel that you get in a gas engined car. after driving your 240 for a few months you will (probably) get used to it. the driving style in a 240 is quite different than a gas engine car, being all about momentum and smoothness, and not about snappy acceleration. i rather like driving a 240, enjoying the fact that at most stop signs you need very little braking if you just back off the gas. the brake pads last a very long time, ditto rotors, tires and about everything else.

my $.02

[Angel]

Rear subframe mounts ? I cant think of the technical/catalog term, but my 82 240D (manual everything =) also rubber-bands like letting the clutch out on a pile of jello. I also have done motor mounts, flex discs and diff. mount. I have not yet done rear subframe mounts, and I'm sure there are some posts around here telling how important they are to keep the rear wheels 'located' properly. If there is flex between the driven wheels and the body, then it'll create that rubber-bandy feeling. I dont expect it to start feeling like my wifes Impreza, but, there is room for improvement.

(oh, and the fact that its a 20 year old, 3000lb car doesnt help either =)

[t walgamuth]

i have had a lot of 123s with more than 200,000 miles and have never changed the rear subframe mounts.... yet.

[dabenz]

It's called engine torque. Diesels have their torque in the lower rpms, gassers have their torque in the higher rpms. You learn to step in and out of the foot throttle gradually, and it forces you to plan ahead and pay more attention to driving and less to the radio and cup holders.

[R Leo]

Remember, the manual 240 has an EXTREMELY low (high numerical) final drive ratio. Coupled with a lot of flywheel mass and torque you get that jumpyness. FWIW, I have a parts car that was an '85 300D converted to a 240 manual. It had a 2.88 : 1 final drive instead of the 3.70 to something that the stock 240 has. At start-up, that car did not exhibit any of the jumpyness I've come to associate with my W115. I think it simply didn't have the leverage to jump as bad with those tall gears.

[jpmaynard]

thanks for the info. I love driving the 240 because it does have such an art to it. When someone else steps out of their golf or jetta and jumps into the 240, they always get the stuttering starts . i have definetly learned how to drive as smoothly as i can with momentum etc., but it just feels like something other than gearing, torque etc.