1985 300D W123 Transmission Fluid - PeachParts Mercedes-Benz Forum

rmmagow · #1 06-28-2011, 02:30 PM

Way too much info here!! Just a couple of questions. I am going to change my transmission fluid including the torque converter drain and new filter.
I am looking for a recommendation (brand name) of a modern DEX 3/4 fluid to use for this change. I do want to go synthetic, but not this time around.

2, a lot of threads include tranmission type, 722.xxx etc. What type is the transmission in my car? it has not ever been changed.

I am going to buy a case of transmission fluid, 12 qts. That should be enough. I am also going to do this withthe car on ramps, that OK?

185,000 miles, shifts hard but no slip or flare. I'll play withthe modulator after I get the underside cleaned up a bit.

Stretch · #2 06-28-2011, 02:48 PM

Quote:

Originally Posted by rmmagow

Way too much info here!! Just a couple of questions. I am going to change my transmission fluid including the torque converter drain and new filter.
I am looking for a recommendation (brand name) of a modern DEX 3/4 fluid to use for this change. I do want to go synthetic, but not this time around.

2, a lot of threads include tranmission type, 722.xxx etc. What type is the transmission in my car? it has not ever been changed.

I am going to buy a case of transmission fluid, 12 qts. That should be enough. I am also going to do this withthe car on ramps, that OK?

185,000 miles, shifts hard but no slip or flare. I'll play withthe modulator after I get the underside cleaned up a bit.

You should have a 722.3 transmission

I only use Kroon oil - but I'd be shocked if you could get it!

I think you need Dexron 2 by the way...

12 qrts is that really about 13 litres? Well if so yeah that's enough - almost twice as much as you'll need.

You could do the change on ramps if you wish - but when you remove the sump for the filter you might get more of a shower than you would with the car on the level.

In my 722.1 that I'm rebuilding I estimate there was about 1 litre left in the transmission when I dismantled it - so you'll never get it all out anyway... and there's the oil cooler...

rmmagow · #3 06-28-2011, 05:40 PM

I'm sure I can't get Kroon here! New name to me. I can't get Dex 2 either, only Dex 3/4 as far as I can tell. I'm going to poke around a bit more but I think that Dex 3/4 should be OK, I've read about folks using Amsoil in their boxes but I'm reluctant to go this way the first time in case I screw up. I'm pretty sure I'm going to get pretty dirty here anyway.

Stretch · #4 06-29-2011, 10:52 AM

Castrol manual gear box oil and differential oils seem to be good. I've never tried their ATF though - but I use their engine oil all the time => GTX diesel and GTX diesel magnatech. I've only had good experiences with Castrol despite them having a reputation in the 1980s in the UK of being sludge forming oils... if that was the case they've certainly sorted themselves out now for motor oils.

BoiseBenz · #5 06-29-2011, 11:43 AM

Quote:

Originally Posted by rmmagow

I am going to change my transmission fluid including the torque converter drain and new filter.

Many here, including I and my ASE tranny-shop-owning buddy, suggest NOT to drain the converter, lines, etc on an older, condition-unknown transmission. Wayne's contention is that such "violence" rapidly dislodges accumulated detritus, leading to seal and valve-body trouble soon after. He says that something like 20% of his rebuild business got a recent flush (at Jiffy Lube, etc).

Just drain the fiveish that will come out of the pan, and slap on a new filter.

Quote:

Originally Posted by rmmagow

I am looking for a recommendation (brand name) of a modern DEX 3/4 fluid to use for this change. I do want to go synthetic, but not this time around.

Any brand-name DexIII should be fine.

Quote:

Originally Posted by rmmagow

2, a lot of threads include tranmission type, 722.xxx etc. What type is the transmission in my car? it has not ever been changed.

You have a 722.3xx (where xx indicates modulator style, speedo drive, etc). Look on the right side of the transmission body, JUST ABOVE the pan. You will see a long string of numbers with "722.3xx" hiding in the middle.

Quote:

Originally Posted by rmmagow

I am going to buy a case of transmission fluid, 12 qts. That should be enough. I am also going to do this withthe car on ramps, that OK

12 is more than enough, ramps are fine.

Quote:

Originally Posted by rmmagow

185,000 miles, shifts hard but no slip or flare. I'll play withthe modulator after I get the underside cleaned up a bit.

Fix your vacuum leaks before you do any tuning.

Your new filter should also come with a pan gasket; make sure it's the right type (six or four bolt) before you drop the pan.

rmmagow · #6 06-29-2011, 12:18 PM

I guess I'll get the Castrol DEX 3/4 fluid. I've used their products for years. A drain, filter swap and refill it is. The transmission is working very good and I want to keep it that way. I broke the vacuum line from the booster to the vascuum pump. I put in the new one and the car is shifting a bit smoother. I am thinking the old vacuum lines one-way valve may have been getting tired. I am not sure when the fluid was last changed but overall the car appears to have been cared for so I don't think I'm draining 100K mile fluid. It is still red and smells OK. Doing a front bumper to back bumper maintenance on the car just to give me peace of mind next winter. I drive it in the very cold but try not to use it in the snow and ice. My 26 year old daily driver :-)

oldsinner111 · #7 06-29-2011, 12:22 PM

I run trick shift or sync atf.both cars

sixto · #8 06-29-2011, 01:41 PM

Should be a 722.315 if it's not a California spec car.

Is there a Dex 3/4? I hope you don't mean ATF +3/+4 equivalents for Mopars.

Sixto
87 300D

rmmagow · #9 06-29-2011, 04:07 PM

Quote:

Originally Posted by sixto

Should be a 722.315 if it's not a California spec car.

Is there a Dex 3/4? I hope you don't mean ATF +3/+4 equivalents for Mopars.

Sixto
87 300D

You know, I'm not really sure about he DEX 3/4 question. I'm stopping in Napa after work and will talk to the folks there about what I want to do. Barring that, I may just buy fluid from MB but I think any modern DEX is supposed to be OK.