Tranny & Diff Fluid Opinions

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TripleJackInGA

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Getting ready to drain/refill the tranny and the diff in my 72 Slant 6/Automatic.

I know Dex III is recommended in the tranny, but read some people run, or you can run Type F. Opinions?

Also, what are you guys running in your diffs?

This is on a daily-driver. Looking for the best bang for the buck. Not looking to spend a ton right now, so spare me thge Amsoil/Royal Purple recommendations.

Thanks!
 
I like Type F. You'll get as many opinions as there are.......elbows, but type F works well. you're probably gonna end up in the 2 gallon area for a complete drain and refill including converter. As for the diff, fill it up to the bottom of the fill hole. Right when it starts to dribble out, it's full.
 
StrokerScamp said:
I like Type F. You'll get as many opinions as there are.......elbows, but type F works well. you're probably gonna end up in the 2 gallon area for a complete drain and refill including converter.
Click to expand...

Just dropping the pan doesn't drain the converter though, right? I'll grab 2 gallons just in case.
 
Mine didn't have a drain plug. Word of advice I dropped my pan by myself. I am not an expert nor do I have a lot of experience but resist the urge to tug on the pan and be prepared to be covered in tranny fluid. That was something I didn't expect. Also Oreilly Auto has in stock a nice rubber gasket but I recommend you put a little clean fluid on it when you put it on. Seems if you put it on dry it leaks a little. If you have done this before just ignore my newbie ramblings. :D
 
Draining the pan tip: Leave one of the bolts in the front pan rail. remove the rest in a back and forth method from one side to the other going around to the back. Have your drain pan ready toward the rear. Slowly remove that last rear bolt while leaving the front one in place. This will allow the fluid to drain from the rear. control the pan drop with your hand until you remove the rear bolt completely. Then slowly loosen up the last bolt in the front while holding the pan. Lower it slowly and allow it to drain into the pan. Depending on your crossmember configuration, it may be necessary to do this rear to front instead of front to rear, but the process is the same.
 
The (objectively) best Torqueflite-compatible trans fluid on the market until recently was Chrysler Mopar ATF+4. It is misunderstood by some to be "too slippery". In fact, ATF+4 is a significantly better fluid in every way than Dexron -II, -III, or -IV and ATF+ (+2, +3), and it does not cause, promote, or aggravate slippage. It maintains the specified viscosity across a temperature range that's wider at both the hot and cold ends, its lubrication and antiwear properties are better, it's more resistant to oxidation, sludging and varnish formation, and it smells better. It might even taste better, I don't know. There's an extremely detailed Chrysler Engineering paper comparing every aspect (except taste) of ATF+4 vs. ATF+3, ATF+2, ATF+, and Dexron-III/IV.

Then along came GM's Dexron-VI, which is another extremely high performance fluid (where "performance" refers to all the things a trans fluid has to do...lubricate both metal-and-metal and metal-on-friction without screwing up the frictional elements' ability to grab and keep hold of the metal, remain stable when cold and when hot, resist foaming, resist oxidation, etc).

The RWD Torqueflites really don't need anything more exotic than a good-quality ordinary Dexron (present spec is the newest Dexron VI, though you might still find some older or off-brand Dexron IIIe or other previous Dexrons on the market). I do run ATF+4 in mine, and they all seem happy with it. But the main point here is you really don't need to sweat it. You don't need to spend unnecessary money on exotic-brand fluids or special "race" fluid.

Fact is, Type-F is an archaic fluid with seriously inferior performance by just about every measure. Torqueflites will hold up fine with Type-F, which is mostly an illustration of how rugged the Torqueflite is. There are much funner ways of demonstrating that a Torqueflite is robustly enough engineered to withstand abuse than to use an (objectively) inferior fluid.

As for the diff: The correct viscosity grade of a good brand of synthetic gear lube. 80w90 or 90w140 depending on how loose and sloppy your particular rear axle is. Make sure to use the correct anti-slip additive if you have Sure-Grip.
 
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