Dear friends:

I'd like to have a poll to see what fluid (Mobil 1 ATF or Mobil 1 10W30) people would prefer to put in their W123's MANUAL transmission.

I go for Mobil 1 10W30 because Red Line MT fluid also has a 5W30
or 10W30 viscosity

Thanks!

Eric

I go for Mobil 1 10W30 because Red Line MT fluid also has a 5W30

Redline MT has friction modifiers that let the synchros in the transmission work better. I have had Mobil1, Royal Purple, Amsoil and generic lube in my VW and the GM truck manual transmissions. All these lubes feel notchy. NOTHING shifts as well at the Redline. SMMOOOOTTHH! Try it and you'll be a believer. RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

You should use Mobile 1 ATF, since these transmissions call for ATF...

How about p/n 000 989 26 03 (Mercedes Manual Transmission Fluid)?

__________________
2008 GL320CDI 6K
1970 280SL 112K
1982 240D 210K (Sold)
1973 220D 220K (Sold)
1967 200D 160K (Sold)
1992 400E 139K (Sold)
1988 300E 148K (Sold)
1987 300D 257K (Sold)
1991 300E 108K (Sold)
1987 300E 131K (Sold)
1978 300D TMU (Sold)
1980 300D TMU (Sold)
MBCA Member

I vote for Mobil 1 as the book says ATF why would you want to not use ATF?

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Redline MT90 Manual Transmission Fluid Synthetic (1.4 qts )

__________________
1983 240D 4 sp manual 260K

I vote for Mobil 1 as the book says ATF why would you want to not use ATF?

The book also says to use oil with ratings that were obsolete 15-20yrs ago. Why not take advantage of progress in oil technology? MTL is a special lightweight oil that is specifically designed to be used in place of ATF in manual transmissions. Incidentally the MT90 is the equivalent to 75-90w gear oil for use in transmissions that spec that as lube. RT

__________________
When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

I want to change the 240D's fluid to Red Line, but can't seem to find it locally. Where do you guys get it?

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Rick, call the local speed shops and ask. The local indy in Austin, TX had it on the shelves. Redline can also tell you where a local dealer is or buy in direct online. www.redlineoil.com RT

__________________
When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

RT,, which indy shop was that ? ( in Austin)
Can't get that site to work,, not your link a problem, had tried them before ....

RT, then by your logic why not use MTL in auto trannies? The spec is for ATF, and taking advantage of new technology means using Mobil-1 ATF instead of dino ATF. No motor oil or gear oil should go in there. I haven't heard of anyone who has used alternate (non-ATF) fluids and been happy with the results. Most people find synthetic ATF to be a tremendous improvement over dino Dexron. Incidentally, what fluid did YOU put in your custom W123 manual?

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Redline's web site indicates that its MT fluid has a viscosity that is equivalent to SAE 5W30 or 10W30. Gear oil SAE 75-80W90 is too thick for manual transmission.

Eric

gsxr,

The reason MB specifies ATF for their manual transmissions is mainly due to the fact that the Fatherland is a significantly colder climate than most places. ATF was considered better than typical gear oils of the old days because it flowed at these low temperatures and gear lubricants didn't.

Consequently it is tough shifting a transmission for the first few minutes or more when you start up at near zero degrees F with transmission full of gear lubricant. ATF seemed to address this issue adequately and did not result in rapid damage to other aspects of the transmission in the hands of a rational operator. Like cabbies in the Fatherland, who performed maintenance on their cars religiously and limited the number of quick starts and racing shifts to preserve their profit margins. In those days the cab driver was also the cab owner. May still be that way over there.

Redline's MTL has about the same viscosity as ATF's at low temperatures where it is important to improve performance, and they offer added protection of extreme pressure additives for gear contact surface wear reduction, as well as friction modifiers to make the synchros perform better with less stress and wear.

Given the synchros are the weakest link in nearly every synchromesh transmission, it is not unreasonable to seek a product that addresses this issue now that it is available. Until recently this additive was not available for any ATF, however, Redline has recently begun to offer an ATF product that also contains this friction modifier (D4 ATF). It is, like MTL, a synthetic GL-4 gear oil, with fewer of the extreme pressure protection additives and viscosity modifiers (for higher temperatures). D4 ATF is also recommended by Redline for manual transmissions that manufacturer's recommend ATF be used in if the extreme pressure additive package is not necessary.

Since I live in a place now that is far less frigid than the Fatherland in Winter, and far warmer in Summer, I have opted for the MTL product. I have been using it in my cars for pretty close to 15 years. I have yet to ruin a transmission and only have one more kid to get through the learning to drive a manual stage. Believe me, the 1982 240D 4-speed has done a few tricks at my daughter's hand that (and foot) I have never considered possible before, and my son is very busy stressing out the 1986 190E 2.3-16 5-speed on a regular basis. So I consider the extreme pressure additives necessary.

The point is, not only have the ATF products improved over time, so have the other options, and now the choice of ATF vs. Synthetic ATF vs. Synthetic GL-4 gear lubricant vs. dino GL-4 vs 10W30 engine oils is more of a multi-dimensional decision than it was in the late 1970's. The choices today can be between technically sound alternates and based on how each fits your operating envelop (environment and driving style).

Hope this helps, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Thanks all (especially JimSmith) very much for responding to the poll.

123c: you must be a Democrat :-) Me too hehe

Eric

Jim, interesting info! I know there was an issue with the additive packages in most gear lubes, that were NOT happy in MB manual transmissions. Apparently RedLine's specific formula works OK, since you have it in at least 2 of your manual MB trannies (I think) with no problems. However I still would not use any motor oil (10W-30, etc) or any gear lube besides MTL. Sounds to me like the 2 viable choices are down to synthetic ATF and also MTL. Do you really think there is that much difference between the ATF and (Red Line) MTL products? Thanks again for the info, btw!

__________________
Dave
Boise, ID
Check out my website photos, documents, and movies!