Technical Refilling a parially empty TH350 Transmission.

Number ONE is I don't trust my Mickey Mouse aftermarket plastic dipstick.
It's a TH350 in my '47 Ford coupe.
I pulled the tailshaft a few days ago to replace the rear bushing while also replacing the front yoke.
Lost a lot of transmission fluid out the open back.
I did not pull the transmission pan beforehand, only the tailshaft.
I hit 4 quarts while refilling and got somewhat of a reading. Slippery goofy stick, hard to read.
I finally added in a 5th quart and it reads between hi and low depending on the side of the stick you read.
Very misleading.
How much fluid should I be adding after reinstalling the tailshaft? I don't trust this slimy plastic dipstick I've got.

 

If you trust the length of the dip stick you could drill a series of small holes in it to make it easier to read.
Also giving the fluid time to fully drain from the DS tube before you check it helps

 

Add two quarts after it fully engages in D and R, when running it thru the gears.

Or get a real dipstick and tube...although it's usually a bitch to install it with the trans in the car, even if it does clear the firewall.

It's pretty hard to say how much fluid it takes to replace what is lost, since they have a tendency to partially drain the converter back into the pan. One trick (too late for you, of course) is to catch all the old fluid in a drain pan.

 

Yes, it's too late to measure what I lost. Some dropped into a shallow drain pan underneath, a lot overflowed onto the floor and about 5 pig mats fully absorbed the rest.
I had no clue I was going to loose so much fluid when I tugged on the end of the tailshaft.

I like the idea of tiny holes drilled in the lower length of the dipstick.

 

Pull the pan ,change the filter and refill.not only give some piece of mind but also let you know where full is on your dipstick and mark it.

 

it holds alot maybe 12 quarts

 

Glad I asked. Didn't know it held that many quarts.

 

don't do what my son did today, I guess he didn't understand when I said put in one gallon...he put in two...spilled out the vent onto the floor, and made a mess.

 

Squirrel......Embarrassed to admit it but I too pulled a similar blond moment on my daily driver Eldorado.
It's a Northstar engine, holds 7.5 quarts.
I poured in the first 5, walked away from it for about 2 weeks for another project then returned to it not clearly thinking.
After the second load of oil went into it there wasn't a dry spot in my driveway or garage where it was parked.
I never knew oil could leak out of so many places.

 

It's hard to guess,but my way of dealing with a transmission fluid loss is just add a quart and run the car and put it in gear,,if it fails to go into gear add another quart until it moves under it's own power.

Drive the car around the block,if it's slow shifting or doesn't shift properly after it has warmed up add more fluid.

Believe me,if it doesn't want it,the tranny will push it out the filler,,you really don't need to ask me how I know. HRP

 

Stock Turbo 350s with a 12" torque converter and a conventional in radiator cooler and a stock pan hold right about 10 quarts of fluid. If the torque converter, pan, trans cooler etc are not stock the fluid amount will vary.
One way to know the fluid level is correct without the correct dip stick, is to have the car level and loosen up the pan bolts while the car is running. Assuming it is overfull, it will drain the excess fluid. Once it has stopped running fluid out, tighten the pan.
This will be messy and then you can drain the fluid into a clean empty drain pan and replace the pan gasket, reinstall the pan.
Reinstall the fluid you drained out. If you have a stock depth pan it will be roughly 3 -3 1/2 quarts on a refill.
The correct fluid level is basically at the pan rail of the case.
Bill

 

In my experience with the TH350, if the trans slips when you put it in gear, it's at least two quarts low. So if you fill it to the point where it engages properly and then add 1.5 to 2 qts, you'll be pretty close to the "full when hot" mark on the dipstick.

 

I hit 4 quarts while refilling and got somewhat of a reading.

I've never seen 4 quarts comeback out of a tail shaft let alone more than 4.

 

It took me 4 quarts to fill my TH400 back up after a few weeks of work. There was a lot of oil dri used, for sure. Over time, the stuff just slowly leaks out of the torque converter. I have a plastic plug I use on 700R transmission but it doesn't fit the TH400. I'd love to know where to get one.