Auto transmission Fluid Change Questions

[MFalkinham]

Hey guys, I tried searching the archives for answers, but figured it would be best just to ask.



I want to change the transmission fluid in my '92 W350 automatic tomorrow, and replace it with Amsoil. Will 12 quarts be enough to do the job including the torque converter?



Also, after dropping the pan, changing the filter, replacing the pan and refilling with new fluid, I want to flush the old fluid out of the TC. Which transmission cooler line should I remove and route to a bucket in order to do this? I only flush one quart at a time to avoid running the pan dry.



Thanks in advance!



- Mike

 

[y-knot]

For the fluid 12 QTs will do, the book says 9-12. 5Qt's depending on model, so you'll be fine.



On the trany the rear line is the one that needs to be disconnected and a piece of 3/4 tubbing slipped over the end with the other end in the bucket. After the pan is bolted back up, fill the pan as normal then start the engine and allow the fluid to pour out into the bucket. After 2-3 Qt's has poured out, top off trany and do again, stop when fluid is bright red.

 

[BushWakr - RIP]

Another way to do this is when you have the pan off to do the filter, you can loosen the 10(?) small bolts that hold the valve body in place (about 3 full turns) and you'll have most all of the fluid drain out by syphon action.

When you're done you can snug up the bolts to spec and begin the refill.

You should pour in about half the fluid, then with the trans in "N" start it and add the rests. You need to use "N" though, not "P" because it is possible to run the pump dry and pooch it.

Bring it up to operating temp (180*F) and check level.



Oh I personally don't like the flush method because you've no idea what you may be pushing back into the system. That's just a personal bug on my part though.



One last item. The full synthetics like Amsoil have a faily high lubricity package in them.

The more there is, the more they seem to promote slippage, which in turn can generate heat and wear. I'd personally not use more than a semi-synthetic or mix it half and half... again, just my thoughts Mike.



bob...

 

[MFalkinham]

Guys, thanks for the great advice. Unfortunately, this project was put on hold due to the transmission filter/gasket kit being out of stock at the local parts store. I'll just do it next weekend instead.



I've taken the Pastor's advice to heart regarding fluid choice. Because of the non-lockup nature of our torque converters, I don't think more slippery would be best for preventing heat. I'm going to use standard Dexron-III with a LubeGard additive. I've had good luck with this combination in the past, and for my light towing needs it is a cost-effective solution.



I am a little afraid of wrenching on the valve-body, though, so I'll use y-knot's suggestion of pulling the rear cooler line to flush the converter.



Thanks again!



- Mike