Manual Tranny Issue - PeachParts Mercedes-Benz Forum

pj67coll · #1 11-17-2006, 05:17 PM

81 240D, 4spd manual tranny, 381K miles. I'm trying to determine if my problems are just a wore out clutch or something more like synchro rings or maybe just that the whole thing is too messed up to bother with.

Impossible to shift into reverse without grating badly unless I first shift into first or second and then it will go in without grating. Biggest problem is difficulty shifting up from second to third and down from second to first. It will grate in both directions when second gear is involved. I've taken to shifting directly from first to third and bypassing second altogether which is interesting to say the least but at least bypasses the grating.

Do I investigate clutch or just try to source a new tranny?

- Peter.

rudolfgreen · #2 11-17-2006, 05:31 PM

think '81 is the year they switched from 10W-30 to automatic trans fluid.. would use synthetic either way.
just be sure not to use typical manual trans gear oil.

stcbenz83 · #3 11-17-2006, 05:34 PM

reverse is always a week gear. i always shift mine from 1st or 3rd to reverese, cause if i dont, have to hold the clutch in for like 5 seconds to avoid scrapping in reverse. never bothered me. as for the other ones. try changing the fluid. maybe the syncros are just gone, in which case, just double clutch. have u tryed double clutching second?

pj67coll · #4 11-17-2006, 06:29 PM

Double clutching and changing oil. I've not tried either but will do so. Thank's for the suggestions. Just one question though. Why would I avoid manual tranny oil in a manual tranny?

- Peter.

rudolfgreen · #5 11-17-2006, 06:57 PM

it is the "typical" traditional manual gear oil to which the reference is made to.
some "manual trans fluid" is thick like a gear oil, and some is thinner similar to auto trans fluid.
thick gear type fluid will just jam your synchros up worse. there are many thoughts either way through the searches.
personally, am going to use AMSoil Synthetic 10W-30Type Manual Transmission Fluid in the '82.

DieselAddict · #6 11-17-2006, 07:07 PM

Red Line MTL is another great choice. But first I'd check the condition of the clutch disc using the the clutch wear tool mentioned in the Haynes manual. Did you try shifting slower into the troublesome gears? That might help you in the meantime.

t walgamuth · #7 11-17-2006, 07:43 PM

sounds like your clutch is dragging. could be a failed finger on your pressure plate. if that the only cure is a new pp.

or could be the clutch hydraulic not working fully.

too heavy oil, i concur, could cause trouble too.

good luck.

tom w

#8 11-18-2006, 01:28 AM

Quote:

Originally Posted by pj67coll

Impossible to shift into reverse without grating badly unless I first shift into first or second and then it will go in without grating.

100% Normal. The reverse gear is not synchronized, so it will always grind unless the clutch in not spinning (You stop the clutch disc by putting it into 1 or 2).

The other grinding is just from wear (Mine will often grind when going into 2nd). I suggest you use Redline MTL, it should noticeably reduce grinding and extend the rebuild time by a few thousand miles.

Gear oil is too thick/heavy for this tranny. It was designed with ATF/10W30 so it needs thinner oil. If it's grinding really bad and/or you can't get Reline oil, 15W40 is as thick as I would dare go.

Gurkha · #9 11-18-2006, 07:59 AM

On my ZF 300TD 5 speed, I have decided to switch from ATF to Delo 400, in summers, ATF just turns too notchy and balky, reverse gear especially becomes difficult, after I switched over to Delo 400, its a transformation, shifts are smooth and flawless, reverse is well behaved as well. Now that winters is coming, I will see how Delo performs as compared to ATF but don't think it can be that bad.

t walgamuth · #10 11-18-2006, 08:15 AM

on a tranny worn so much it was notchey going into second i put in rotella 15w40 and it smoothed out.

i disagree that it is normal to have to shift into second to get into first without grinding. if you wait a couple of seconds it should go in without grinding at all. if it wont, your clutch is dragging a bit. this is not normal and will get only worse. so should be addressed.

tom w

Gurkha · #11 11-18-2006, 08:45 AM

Tom,

Glad to hear another person using engine oil, my tranny is relatively new and not abused, yet the Delo 400 has made far better shifting, how is winter being handled by your Rotella in the tranny by the way.

t walgamuth · #12 11-18-2006, 10:25 AM

just fine. i wouldn't run it in a tranny that wasnt well used. but in your hot climate i might.

tom w

vahe · #13 11-18-2006, 10:46 AM

Are the manual transmissions same on 77-83 240D's? Also if someone wants to buy a re-built are they available?

Vahe
240D 77 350K

t walgamuth · #14 11-18-2006, 10:50 AM

there may be some difference but i think those years are probably interchangable. rebuilt may be available but they are so bulletproof that buying used is not that much risk.

tom w

#15 11-18-2006, 11:02 AM

There are two different trannies. One with an aluminum bell and iron body, the other is a one piece aluminum body. They will both bolt in place but the shifter levers are different.

Also, a 4-speed from the W115 body will also work.