Oil for an old Mercedes manual tranny

[OM605]

Hi everyone. Couldn't help it, bought another old diesel Benz recently. The car is a 1997 C250 Turbodiesel that has done 370k km. Shifting from 2nd to 3rd is quite notchy and makes the bad flex disc clunk quite hard (still have to replace that). I think i have a worn 3rd synchro ring since all other gears are smooth, which eliminates any clutch issue. If i want the shift to be smooth, i have to either wait a bit in neutral or double clutch.

These manual trannies are supposed to take ATF up to around july of 97. At that point they switched to GL4 oil. There's a MB paper stating that earlier transmissions can be switched to the newer oil.

The oil i drained was not ATF and it looked like liquid metal. I refilled with Dexron III, there was a slight improvement but 3rd was still unpleasant. I've just replaced it again with some Total semi synthetic 75W80, seems a little bit better but haven't driven the car long enough.

My options are:
- Try other oils (synthetic vs dino, redline, amsoil etc)
- Try an additive
- Live with it and learn to drive it smoothly
- Transmission rebuild (not going to happen)

What would you do/try? I'm thinking about sticking to something in the 7.5-9cSt range. Please refrain from posting variations of "use ATF because that's what MB blablabla".

 

[slacktide_bitog]

Valvoline Synchromesh is widely available

If you want synthetic, there's Royal Purple Synchromax

 

[wings&wheels]

I have had positive experiences w/ Redline MTLs in various European vehicles, except our Porsches. I define 'positive' as at worse, not feeling any worse than whatever it replaced, to a vast improvement as in the case of our BMW 2002, shifts feeling much better than with the conventional gear lube that was in it.

For whatever reasons, the 996/986 transaxles work best w/ OEM fluid, but this is a corner case.

I'd consider their MTL.

 

[JavierH19]

Any Synchromesh fluid you can get from the local parts store will work. That old unit isn't too picky.

 

[atikovi]

MTL® 75W80 GL-4 Gear Oil

Popular for BMW (before 1993), Honda and Acura, Ford Focus, late-model Mini Cooper, Dodge & Jeep NV 1500, 3500, and 5600

www.redlineoil.com

Has helped hard shifting especially when cold as well as grinding on a few cars I've put it in.

 

[kschachn]

Post some pictures of this beast, I love old(er) MB cars.

 

[JavierH19]

MTL® 75W80 GL-4 Gear Oil

Popular for BMW (before 1993), Honda and Acura, Ford Focus, late-model Mini Cooper, Dodge & Jeep NV 1500, 3500, and 5600

www.redlineoil.com

Has helped hard shifting especially when cold as well as grinding on a few cars I've put it in.

I'm not sure that's available in Brittany. He's not in the US it seems.

 

[OM605]

Post some pictures of this beast, I love old(er) MB cars.

I will for sure!

I'm not sure that's available in Brittany. He's not in the US it seems.

It's available here, about 27€ for a quart, which isn't cheap.

 

[OM605]

Drove the car today and the 75W80 i have in there right now doesn't solve anything and even seems to make shifts a bit rough for the first minutes of driving when cold. At least i feel like the fluid is more suited to the transmission than ATF in term of AW and EP additives. Maybe i could try something similar but synthetic and/or thinner. I guess that viscosity in a manual is a trade off between shifting quality on a cold transmission and gears wear. Do synthetics MTFs usually improve shift quality in oil trannies or the opposite?

 

[MolaKule]

Hi everyone. Couldn't help it, bought another old diesel Benz recently. The car is a 1997 C250 Turbodiesel that has done 370k km. Shifting from 2nd to 3rd is quite notchy and makes the bad flex disc clunk quite hard (still have to replace that). I think i have a worn 3rd synchro ring since all other gears are smooth, which eliminates any clutch issue. If i want the shift to be smooth, i have to either wait a bit in neutral or double clutch.

These manual trannies are supposed to take ATF up to around july of 97. At that point they switched to GL4 oil. There's a MB paper stating that earlier transmissions can be switched to the newer oil.

The oil i drained was not ATF and it looked like liquid metal. I refilled with Dexron III, there was a slight improvement but 3rd was still unpleasant. I've just replaced it again with some Total semi synthetic 75W80, seems a little bit better but haven't driven the car long enough.

My options are:
- Try other oils (synthetic vs dino, redline, amsoil etc)
- Try an additive
- Live with it and learn to drive it smoothly
- Transmission rebuild (not going to happen)

What would you do/try? I'm thinking about sticking to something in the 7.5-9cSt range. Please refrain from posting variations of "use ATF because that's what MB blablabla".

Nothing is going to cure a worn tranny but Try this:

MT-LV 70W/75W GL-4 Gear Oil

Meet our newest addition to the GL-4 family!

www.redlineoil.com

which is closer to the viscosity of the Dexron III.

 

[userfriendly]

I’m thinking tractor hydraulic fluid. THF has the viscosity you are looking for and is GL-4. I just bought a 5L jug of Shell Spriax S4 TXM for my JD lawn tractor. It’s J20C for warm weather. J20D is for cold weather. Synthetic varieties pass both J20C & D. S4 TXM show’s viscosity @ 40C 60 & @ 100C 9.4

 

[Bailes1992]

Sounds very much like the Land Rover R380. They started life on Dexron IID ATF and then they changed the spec to MTF-94 which was a 75w80 GL-4 type oil.

I've been running Castrol Syntrans FE in our R380 for a few years now. It's an MTF that has the viscosity similar to the originally specified Dexron IID. Shifts very smoothly indeed.

 

[ceecbtg]

Drove the car today and the 75W80 i have in there right now doesn't solve anything and even seems to make shifts a bit rough for the first minutes of driving when cold.

It's like expected. Anyway you need to wait any miles with new oil. If after anytime it is not working better for you, you can try any good FE oils classic GL4 or newer GL4 like:

Classic: Ford 75W FE WSS-M2C200-D2, Redline MT-LV 70W75, Castrol BOT 303/350, GM 93165694 75w and syncromesh, Amsoil MTF Synchromesh, Honda MTF, Valvoline Syncromesh, Tutela/Mopar Gearforce 75w, VW G0xx175

Newer: Fuchs Titan Sintofluid FE 75W, Meguin MTF GT3 70W-75, BMW LT1/2/3, Ravenol MTF-3 75w, VW G0xx512/527/726

 

[Sequoiasoon]

I used BG SynchroShift II in my old Corolla. It stopped the light grinding I was having. I had tried multiple other fluids first that didn't help or slightly worse.

The BG was recommended by a friend who was a BMW mechanic. They were using it at the dealership for the cars with same issue of light grind from synchro's. I think it was a TSB at the time. It solved my issue in that when 3 places said I needed a rebuild.

 

[OM605]

After driving the car for 1500 km since my last post, It has consistently been the opposite of what i said earlier. Shifting into 3rd actually gets worse after a bit of driving when everything is up to operating temp. It really seems smoother when cold. Hot, it will always make a clunky sound no matter how slow/smooth i try to shift.

 

[Astro14]

Hate to say it, but this needs a rebuild. Go up a bit in viscosity if it’s notchy when hot, but you’re only postponing the inevitable on a 370,000 km transmission.

 

[OM605]

Mmh... It's not too bad, i just have to shift into 3rd really slow when hot or double clutch it to make it smoother. All other gears are very good. Honestly i can live with it for now and play with oil a bit.