Trans filter/ fluid change?

[greazer2b]

I’m about to change Trans fluid/ filter on my 1985sd with 303 trans. I want to drain the converter as well, can some tell me what I need to undo the plug?

And about how much fluid ? I’m sure I would need more.

Thx greazer2b

[rrgrassi]

When I had my w123, had to use a metric allen socket, but I do not remember if it was a 10 mm or not. I did have to use the 27 mm socket a ratchet to turn the crank shaft to get the plug to point to the ground for draining.

I am getting ready to do that to my w124 as well.

[engatwork]

Have 8 qts of fluid on hand. The torque converter allen head plug is small. I'm thinking 5mm but that may not be correct.

[vstech]

It is 5mm
A GOOD 5mm, not a cheapo...
Make sure the bolt head is TOTALLY cleaned out too.

[greazer2b]

Got it !!
I’ll get a good 5mm Allen and 2-3 gallons on fluid.
I appreciate it the help
greazer2b

[Sugar Bear]

2 gallons should be plenty. The Valvoline MaxLife worked well for me. I'd suggest a new copper washer on both the converter and pan plug. An assistant to locate the TC drain plug while the engine is turned is a huge help.

Good luck!!!

[Phillytwotank]

I like to use one of those “mix and measure” buckets. Graduated 5 gallon bucket. Pour all removed fluid in the bucket so I have a pretty good idea of how much oil to put back In.
Remember to fill in stages, especially if you drain the TC. Fluid won’t return to the TC until the engine is started. Oil will come out the vent of the tranny if it gets dumped in there all in one shot.

[tangofox007]

Originally Posted by Sugar Bear

An assistant to locate the TC drain plug while the engine is turned is a huge help.

I rotate the crankshaft with one hand on a ratchet wrench and the other hand feeling for the TC drain plug to line up with the access port. (That might not work for mechanics of limited stature.)

[rrgrassi]

Originally Posted by tangofox007

I rotate the crankshaft with one hand on a ratchet wrench and the other hand feeling for the TC drain plug to line up with the access port. (That might not work for mechanics of limited stature.)

Or those with T-rex arms.

[greazer2b]

With the fluid I was thinking of switching to Valvoline from Stp from autozone.

I’m looking forward to doing this one because my buddy has a lift and good set up and he keeps asking form to come over so I’ll be standing up on this one.

Good suggestions on how to roll over on the plug. I appreciate the help.
Thx greazer2b

[Sugar Bear]

I'd make that switch...

[HughO]

I have done this multiple times and the MB engineers deserve a hand of applause for designing in a torque converter drain. On most cars you have to pull the return cooling line from the radiator and drain out the fluid by briefly(!) running the engine, draining a qt or so at a time while replenishing the with the exact amount of new ATF. when the fluid looks like new ATF you are done. If you just bought the car it is probably OK to drop the pan and check for damage but I have never found enough to bother with. Leave the pan alone. I always add a magnefine transmission filter to the radiator return line which both filters and captures suspended magnetic particles:https://www.amazon.com/Magnefine-Magnetic-Inline-Transmission-Steering/dp/B0787KWZPS. NEVER EVER do a transmission flush. Many flushing systems can ruin the transmission.

[greazer2b]

Update: Sorry I’ve been busy with Dr visits so I’m haven’t done my trans service yet on my Federal 85sd

But I i just got a big surprise on my other 85sd California I went out to do my monthly start it up and let it warm up and when I did I pulled the tranny dipstick and the fluid is white does that mean what I think it does ?
Help!!
greazer2b

[Sugar Bear]

Could be coolant due to a leaking trans cooler in the radiator.

Good luck!!!

[JHZR2]

Originally Posted by greazer2b

Update: Sorry I’ve been busy with Dr visits so I’m haven’t done my trans service yet on my Federal 85sd

But I i just got a big surprise on my other 85sd California I went out to do my monthly start it up and let it warm up and when I did I pulled the tranny dipstick and the fluid is white does that mean what I think it does ?
Help!!
greazer2b

Coolant transfer into the atf. Failed radiator. Look in your plastic coolant bottle. Any signs of oil there? It will float on top…

Sorry to hear this. It means have much more ATF on hand.

Supertech at Walmart works well.

Draining the pan and tc and replacing the filter is super easy and clean on these cars. But I’d want the water out of there before doing too much. I’d drain the pan and radiator to see what’s going on and go from there.

FSM I believe says to fill the transmission with 4 QTs, start the engine, then add to capacity.