To mess with the tranny, or leave well enough alone?
 

Hey gang:

Now the the weather has warmed a little, I have decided to plunge back into rebuilding the 240D. I have the tranny out to rebuild the clutch, but now I can't decide if I should open up the tranny or not.

I didn't drive the car much before the clutch went, but I don't recall any noticable problems during the brief time I did drive it. However, upon draining out the ATF I did notice a some metal specks in the fluid. I know this is normal to some degree, especially on an older gearbox. However, there is also a little play in the input shaft.

So the question is, should I mess with it, or just leave it be until there really is a problem?

Also, I decided to take the shift levers off to clean them up. I removed the allen bolt from each and slid the levers out. Everything seemed to go well when replacing them, but now I can't get the middle lever (3-4 lever I believe) to go back on, I can slide the lever back in, but the bolt doesn't line up - whatever it screws into in there moves enough to not allow it to line up straight. What gives?

Thanks in advance.

bump

thoughts anyone?

At that mileage I wouldn't expect any internal issues with the transmission, so I wouldn't open it up. Do check your shift bushings before you stick it back in.

I've never taken the shift levers off one, so I'm not sure what's keeping your's from going back on right.

This is an MT? It was filled with ATF likely for easy cold morning shifts, but AT is a lousy MTF. What did MB spec for it? Likely a 75w- GL4 lube or similar.

Could be poor additives for wear protection, sitting dry, etc. I wouldnt worry about it much unless it is noisy or whiny. Figure out and get the right fluid in there first!

Mention of the clutch going out would be the first clue;)

You say this based on what information?

Most years, the manual called for Dexron III ATF. There were a couple of years where they speced one of the lighter weights of motor oil, but then they switched back to reccommending ATF. In addition to research on this site, I also asked the dealer what to use in my MT 240D, and they also said Dexron III.

Yup, it is a MT. I think MB actually called for ATF Type A. Others have suggested us 10W-30 motor oil. I will think more about what fluid/oil to put in, for now I will refill with some ATF, run it for a bit to clean it out, and then add whatever I end up going with. I am open to suggestions as to what to use, but I also haven't searched much on that topic yet.

I guess I am most concerned about the play in the input shaft, is it alright that there is some play there, I can wiggle it a little up and down.

Thanks Skippy. I thought about opening it up, but then that little voice crept into the back of my head and reminded me of all those other "little jobs" I didn't really need to do that turned into big headaches.

The shift bushing look surprisingly good, perhaps the only rubber parts on this car that aren't falling apart.

I'm sure there's a spec for it somewhere. Don't forget the other end is supported by the pilot bushing/bearing.

In the case of using an ATF in synchromeshes, IMO, I do think transmission engineers have sacrificed wear for cold weather shiftability.

Do note that high-sulfur gear lubes are incompatible with the synchronizers in many manual transmissions.

You definitely have to consider the viscosity of the fluid that the transmission was designed for. The spectrum now ranges from ATF to 75W90 viscosities and therefore a synchromesh GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (ATF equivalent viscosity) to a 75W90 type viscosity of approx. 14.5 cSt, and contains special friction modification additives for synchronizer assembly engagement of brass/bronze, or steel-steel materials.

Current MTL GL4 viscosites are:

1. ATF Series - Type; 6.5 to 8.5 cSt (Equivalent ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series -Type; 9.3 - 9.5 cSt (such as Amsoils MTF, Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt ( Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).

Since GM or Pennzoil Synchromesh (9.3 cSt) fluids are only about 2 cSt higher than ATF (7.5 cSt), I recommend trying it in trannies that spec ATF, since the GM or Pennzoil Synchromesh fluids have about three times the AW and EP additives, and are synthetic blends.

Don't know how far along you are but this sounds relevant: "If it isn't broken, don't fix it."
Good Luck and keep us updated.

+1. But the presence of filings and metal bits indicate an incorrect lube choice all the same. Id be looking at least at an ATF with a GL-4 level of additization to protect the gears.

Okay, I am going to make the smart decision here and leave it alone until a real problem surfaces - probably a week or two after I get all back together ;).

But you guys have given me a lot to think about with the fluid/oil choice. Thanks for your help. I'll let you know what I settle on.