my 4-speed goes BOOM CRUNCH! - PeachParts Mercedes-Benz Forum

bricktron · #1 10-13-2014, 02:03 PM

my 1977 chassis still has the original notchback manual transmission in it. no problems other than the universal weak 1st gear synchro until today. on my way to work i heard a sound which made me think i ran over a loose manhole cover, then a few seconds later a much worse scraping or grinding noise. i thought maybe part of the exhaust had fallen loose and was scraping on the street. i managed to get over to the curb; a benefit of living in hilly san francisco is that one can almost always glide out of the lane in neutral using the street's natural slope.

the transmission fluid had all spilled onto the street and traced a beautiful S-curve as i maneuvered into a parking space. i couldn't see any damage from curbside, but something must have knocked a hole in the transmission's aluminum casing. perhaps the flywheel was out of balance, as it was balanced against a different 617, but not sure if this could be related.

i have a backup tranny which is the slopeback style at home. time to get installing it, i suppose. any advice? the clutch kit in the car was replaced 3000 miles ago. i'm skeptical about doing the job alone - guesses about the shop time required for this job? alternately if any forum members want to offer help i can make it worth your while in beer, food, cash, etc.

thanks folks.

leathermang · #2 10-13-2014, 02:39 PM

I do not get the impression you have actually ' put your eyes ' upon the trans and its leak...
perhaps this was something like a center bearing support that gave way...and took out the rear seal...and allowing the fluid out..
so push a digital camera under it ...with a good light.... from both sides and get a better idea as to your predicament....

bricktron · #3 10-13-2014, 03:33 PM

you're right, i couldn't see a thing at first look. thanks for suggesting a less fatal possibility. i will walk back over to the scene of the crime and take some photos after my next class. next will be figuring whether to have it towed back to a shop or to my house.

leathermang · #4 10-13-2014, 04:00 PM

The trans body is really strong... I think you would have seen something big enough and tough enough to ' take it out' ... and anyway... it would be hard to do that without first taking out the engine pan...
But there are reports and pictures in the archives of things associated with the drive train which actually came inside the car when they gave way.... so this was just way more logical a first thing to suspect...
But it always nice to have a spare part sitting in the wings in case you need it... good planning there....

bricktron · #5 10-13-2014, 06:07 PM

i took another look, did my best at curbside undercar phone photography - and saw nothing in the least revealing. a jack will be required for diagnosis.

bricktron · #6 10-13-2014, 06:26 PM

to be clear, i don't think i hit anything in the street - i like the center support bearing theory - will have to leave it there overnight and come back with my truck and jack tomorrow for a better look. too bad it's on such a slope. thanks leathermang for the advice!!

leathermang · #7 10-13-2014, 06:29 PM

Good Luck.... think positive...