Was dealing with a Mercon SP drain and fill and accidentally got burned in my left shoulder thanks to that exhaust. Second degree burn it seems. While working on it, I was struggling with keeping the hose I was using to pump the fluid in in the fill hole. Made a total mess. So I was wondering if this alternate procedure I thought of would work instead:

1. Drain fluid and measure how much fluid came out.
2. Through the ATF cooler line, fill with that same amount + 1 quart if you think you had a leak.
3. Start car run it through each gear for a couple seconds.
4. Remove fill plug. (Wear heat resistant gloves.)
5. Monitor trans temp.
6. As ATF stream begins leaking from fill hole between 40º and 50º, place filler plug.
7. Shut off the engine, let cool, and make sure filler plug is tight.

Would this get you close enough to the correct ATF fill level? I wish we could get a dipstick for these to make life so much easier.

 

fill it straight away don’t check trans temp

 

I'm not sure if you're being sarcastic or not. Would that not result in either an over or under-filled transmission? Per ZF's official instructions, you must monitor trans temps when filling up. You first fill until a steady fluid stream leaks from the fill port, then start the car, run it through the gears, and fill the rest of the way. Fluid stream will develop again, you must re-place fill plug at 40°C but no later than 50°C.

 

nobody cares everybody fills them right off startup. with fluid expansion it’s like a whole 50ml difference.

if you really tried to any overfill is going straight out the vent

 

If you don't need to change the filter because you're doing a second follow-up fluid change after a filter change to further dilute the fluid which was trapped in the torque converter, then we simply drain, catch all the fluid, measure the volume and top up with the same amount whilst the engine is running but still cold.

You could do the same with a filter change but catching and accurately measuring the fluid is more problematic as it tends to splash around a bit.

Richard

 

I usually try to cap the fill plug when the temp is 30 degrees Centigrade.
The range is 30 to 50.(I like MAX fill)
As long as the start temp is below 30, I just fill and work as FAST as I can and then cap the plug.
Summer here in Texas is close to 30 in the morning so I get it done EARLY.
Winter is more forgiving for time/temp.

 

Yes it is a follow-up drain and fill in this case.

30°C seems to low to me as that is already the ambient temperature. My trans is at 31.4° C after being shut-off overnight.


Anyways, I got it done using the official method. These boxes sure do love the Mercon SP. Feels like a brand new transmission.

 

A little late to the discussion, but I did a fluid change to my 5HP24 using the cooler line as you suggested in your first post, but I replaced the plug at 30 C like motorcarman does.

 

Were you filling through the oil cooler with the engine running? Did you plug the radiator side of the cooler to do this?

 

I had the engine off and a 1/4" tube inside the cooling line, used the mighty-vac to pump the fluid. If you were to start the engine the transmission pump would make a mess.

 

That makes more sense!

 

It won't help you now, but look at this link. https://www.summitracing.com/parts/otc-6792?rrec=true

There are several kits on the market, AFAIK, but note the black adapters. These, along with one or the other of the Motive Products pumps, make filling these ZF units much easier. The d*mn fill plugs seem to always be located too close to the body, or too close to the exhaust.