I wanted to make this thread to get the public's experience on the mileage of your M46/M47, type of gear oil you use, any negatives (or positives) of your transmission, and last but not least, do you enjoy driving it? I ask this because I've driven countless Getrag/ZF transmissions, mainly in BMW's (E30 and E36) and never had any problems with them. On the other hand, I've driven a couple M46 and M47 and was not impressed with them, and currently have issues with mine.
I have a 1989 240 DL (M47) with 170,000 miles on chassis, engine, and transmission. I used ATF Type F fluid (as recommended per user manuals) but I am thinking about Redline MTL soon.
My M47 is very clunky and not swift when it comes to gear shifts, every M46/M47 I've driven is like this. Not sure if this is due to worn synchros (bought the car at 159,000 - still had this issue), improper gear oil or neglected gear oil maintenance, or just the nature of the transmission. In a BMW, Miata, even Porsche 944, selector rod will go into any gear nicely and positively. On M46/M47 its always clunky.
Downshifting in my M47 is even clunkier and will even grind sometimes. For this reason, I utilize double clutching when downshifting (and sometimes upshifting). Basically, clutch in, neutral, rev match to next gear's rotational speed, clutch in, next gear). This will give you smooth and precise engagement of any gear as long as your rev match is within 50RPM of gear speed.
I also found that double clutch downshifting, despite being a longer process "on paper", is actually quicker in the real world than normal rev-matching. Normal rev-matching is clutch in, rev match, then lower gear. However, my selector rod has a "brick wall" blocking it to get into the lower gear for half a second to one second, probably because of synchro resistance. With rev-matching, the selector rod will enter any gear swiftly. So, due to this, double clutching is actually faster than rev-matching.
Double clutching on upshifting, however, is slower than double clutching on downshifting. The 240/740 generally have heavy flywheels, so when you press the clutch in, the revs will drop pretty slowly, too slowly to execute a quick upshift double clutch. You press the clutch in, neutral, then clutch in and engage next gear when you reach the next gear's speed. Waiting for the RPM to drop to the next gear's speed can take a second or two, while simply shifting conventionally will take a second max, but will still be clunky. Exotic cars have the opposite problem, the flywheel is so light that as soon as you press the clutch in, the revs drop so low that they are already lower than the next gear's rotational speed.
I hope to get feedback from you guys, I want to know if I'm the only one that doesn't enjoy the clunky and non-"sporty" characteristics of the M46/M47 transmissions.
I have a 1989 240 DL (M47) with 170,000 miles on chassis, engine, and transmission. I used ATF Type F fluid (as recommended per user manuals) but I am thinking about Redline MTL soon.
My M47 is very clunky and not swift when it comes to gear shifts, every M46/M47 I've driven is like this. Not sure if this is due to worn synchros (bought the car at 159,000 - still had this issue), improper gear oil or neglected gear oil maintenance, or just the nature of the transmission. In a BMW, Miata, even Porsche 944, selector rod will go into any gear nicely and positively. On M46/M47 its always clunky.
Downshifting in my M47 is even clunkier and will even grind sometimes. For this reason, I utilize double clutching when downshifting (and sometimes upshifting). Basically, clutch in, neutral, rev match to next gear's rotational speed, clutch in, next gear). This will give you smooth and precise engagement of any gear as long as your rev match is within 50RPM of gear speed.
I also found that double clutch downshifting, despite being a longer process "on paper", is actually quicker in the real world than normal rev-matching. Normal rev-matching is clutch in, rev match, then lower gear. However, my selector rod has a "brick wall" blocking it to get into the lower gear for half a second to one second, probably because of synchro resistance. With rev-matching, the selector rod will enter any gear swiftly. So, due to this, double clutching is actually faster than rev-matching.
Double clutching on upshifting, however, is slower than double clutching on downshifting. The 240/740 generally have heavy flywheels, so when you press the clutch in, the revs will drop pretty slowly, too slowly to execute a quick upshift double clutch. You press the clutch in, neutral, then clutch in and engage next gear when you reach the next gear's speed. Waiting for the RPM to drop to the next gear's speed can take a second or two, while simply shifting conventionally will take a second max, but will still be clunky. Exotic cars have the opposite problem, the flywheel is so light that as soon as you press the clutch in, the revs drop so low that they are already lower than the next gear's rotational speed.
I hope to get feedback from you guys, I want to know if I'm the only one that doesn't enjoy the clunky and non-"sporty" characteristics of the M46/M47 transmissions.
