Any tips/recommendations when changing Dynaflow fluid?

Guys, hope to be changing the fluid in the Dynaflow on my '50 Special this weekend, or very soon at least, for the first time. I have the Shop Manual which seems to detail the process pretty well, but was looking for any additional notes from someone that's done it first hand. Is it as straightforward as the manual lays out? The only thing that I could think my be tricky is locating the Converter Drain Plugs while up underneath the car; I'll be using ramps and not a lift...

Should the car be in Neutral or Park? Step 2. notes to turn the flywheel to get to the opposite Converter Drain Plug. Will it just turn by hand?

Hopefully I won't have a rough time getting the Bell Housing Cover bolts off. Looks like there is 8 or so.

It also mentions warm-up the transmission...I think I read elsewhere in the book that means driving it around for about 20 mins. Is this correct?

I plan on using Dexron III ATF for the refill.

Thanks.

Forgot, I also have the Dynaflow Service Manual. I'll take a run through that too just it case it calls anything out in more detail.

Warming it up won't accomplish much other than making it uncomfortable. On a 55 a screwdriver between the block and the ring gear will (slowly) turn the engine...if not there are tools that will engage the ring gear to turn it. Most of the time, removing one plug will be all that is needed to drain. If not put a tube (like brake line) in the hole and blow air.

Thanks. I did a little more searching in the shop man. Will probably skip the "warm up" so I'm not cooking myself under there and will try to do some cleaning of excess crud before I remove the housing cover...

I did find in the "removal section" of the Shop Manual that a remote starter button is used in order to turn the engine and tranny combo. Should work, as I know my car doesn't certainly start at the first hint of cranking... Love how some of the details are left out of one process, but added in others!

As for the converter plugs, one is loosened and then the other is removed. Same concept I think as when using the new type detergent bottles, cap is loosened to allow air in and allow better fluid flow and doesn't create a vacuum.

Take care replacing those converter plugs. Mechanic friend of mine said one reason these disappeared over the years is that many inexperienced personnel were cross threading the plugs when reinstalling. That means converter replacement and expense. Regarding turning the flywheel, removing the spark plugs may make things easier as you are not turning against the compression in the engine. I've had good success using Willie's suggestions, though.

Well noted. I'll be very careful on them then. Definitely can't afford that type of issue. I'll report back on Monday of my experience...

I needed to "refresh" the timing mark on the '51 this past week. To turn the engine, I just pulled the ignition lead between the coil & distributor. That way, you can engage the starter and the engine definitely won't start. It's not hard to engage the starter and only turn the crank a fraction of a turn. Down side is you have to go under the car, look at the flywheel, get back up, tap the starter again, go back under... Didn't take too long.

I thought about it, and when I was getting the car running, I would turn the engine with a socket & breaker bar on the big nut on the front of the crank - but that was with the radiator out...

Project went well!! Well, let's say it took longer than I thought, but I did it! However, length of time was due to me being nosey and noticing a really worn Fuel Pump Suction Fuel Line. It's the short "jumper" hose between the hard-line along the Oil Pan and the one that runs to the Fuel Pump. Well of course, took that line off and then managed to break it due to dry rot. Luckily the car was already up on the ramps.

Continuing with the original project at hand...

Bell Housing Cover came off pretty easy, 6 bolts. Ended up replacing one of the lock washers as one was split in half, no major crud build-up inside.

Hardest part was getting the Converter Drain Plugs out! At first they were stuck and after a number of tries, I couldn't get them to budge. Skipped over these and then emptied the pan. Bolt came right out. Be aware though, that nearly half of the fluid in a Dynaflow must be in the Converter. Only about 4 Qts. came out of the pan.

Knowing this, I went back to the Converter Plugs again, again, could barely budge. However, I finally tried turning the flywheel so that the bottom Converter Plug was at about 8 o'clock instead of at 6 or 4 where I had tried in previous attempts. Being that the car was up on ramps I only had so much room to work, but initially loosening the Plugs from 8 o'clock was just enough. I could then rotate the flywheel back around so that one plug was at 5 or 6 which I loosened; but probably could have loosened a bit more. I rotated the flywheel 180 degrees and removed the other plug. Converter drained, but VERY slowly. This could be because 1. I skipped to draining the pan, or 2. I didn't loosen the "top" drain plug enough. As my earlier post mentioned, think new style laundry detergent jug with the push-button pour spout. The flywheel looked clean and dry, a few surface rust spots, quite a bit of factory blue paint still there. The teeth that engage with the Starter Motor were looking pretty good and had a light oil coat on them.

Next step was to put the plugs back in and re-install Bell-housing cover. I torqued them per the Shop Manual, though oddly, I didn't see a torque setting for the Converter Drain Plugs. I installed tightly. If I find a setting in the future, removing the Bell Housing Cover is easy and there isn't any fluid loss from doing this.

I rolled car back off ramp, and I then filled the tranny with the prescribed 3Qts. of ATF and let engine run up to temp in Park. (If you're thinking, wait a minute, didn't he brake the fuel line? Yes I did, and it's still broke. I got a plastic hose splice from Aubochon and it held long enough for the rest of the fill project.) I filled the rest of the way a little bit at a time with more new ATF until the dipstick showed Full. This part is a little tricky as the Manual notes to add to 1-3/4" below full and that the fluid will come up to the FULL level on it's own once it's up to temp. I ended up putting in 8 Qts whereas I think the Manual mentioned 8.5 Qts. I'll continue to monitor for leaks and check to see if it shows over-Full at some point.

Next will be to replace my Fuel Pump Suction Hose...No luck on finding a pre-made one; I'll probably have to have one made. Not much luck in this department yet either though. Shops I contacted yesterday in my area do not, or no longer, offer this service. I also noticed this morning that the plastic in-line splice had melted. I can see a "chrysalis" of plastic coating the outside of the old cloth-covered hose. I will not re-start engine until I replace this line!

Congratulations on getting the job done.

Is this the fuel line you need? http://www.oldbuickparts.com/catalog/up-to-1960-buick-group-fuel-gas-line-1940-53-buick-p-6046.html

Carl

Yup! I figured he or Bob's would probably have it, just didn't have a chance to go thru their catalogs. Was hoping to source something local for a quicker repair turnaround. I'll take a run to NAPA today and if a no-go, I'll be putting another order into CARS... Seems like I always have a list of items to put on my "next order" with him. LOL

Congrats on getting your Dynaflow fluid refreshed. Just wanted to add that the fuel hose listed there is actually a little different than the stock one. The stock one was actually made onto the metal line that goes over to the fuel pump. They were one piece. To use that replacement, you have to cut the old hose off the metal line, put an appropriate fitting on there that will screw into that replacement hose, and flare the end. This is IF your car had the original hose that was made onto the metal line. If not someone may have already performed this operation and you might be good to go.

Hey Robert!! I remember you had some difficulties with your fuel line change a while back. Luckily, the hard lines that are in place on my car have flare fittings already. One on the hard line that runs along the oil pan, and on the one that comes off of the fuel pump. I pulled the rubber line again last night to do some checking around locally today...nah dah; (a golf tee overwrapped in electrical tape and the car up on jackstands is holding my nearly full fuel tank level at bay). I ordered the replacement one from CARS. I should probably give them a call to double-check length... I did see some NOS ones on eBay for Buick, other GM marquees and Ford/Lincoln. I didn't want to take the chance on going back to 50 year old rubber that's been sitting, dry-rotting on a shelf.

That's good then. Sounds like somebody already did the hard work for you. Definitely stay away from the NOS hoses. I bought one of the original style one piece hoses from Bob's. It was NOS and when I got it, it was dry and cracked. I wasn't able to use it but it did provide a good pattern for me as mine was missing the original when I bought the car. Good luck and keep us updated.

Guys. Also forgot to mention that I did use one of those push-button remote starter switches. Clips to battery terminal on Starter motor and to one of the other wires on the relay on the Starter. Worked great, no need to force or creatively turn the Flywheel. Could pretty much bump the engine/tranny around about 25 degrees at a time.

Guys. Also forgot to mention that I did use one of those push-button remote starter switches. Clips to battery terminal on Starter motor and to one of the other wires on the relay on the Starter. Worked great, no need to force or creatively turn the Flywheel. Could pretty much bump the engine/tranny around about 25 degrees at a time.