Bought a 65 Chrysler for a winter beater sometime in the early 70's. Tranny slipped a little. Replaced the filter and put type F in it. Drove it all winter and sold it come spring. Never slipped a bit with the type F.

People keep saying that but it still happened.

Anyone willing to put up the cost of a rebuild for the OP if he goes the type F route and the trans fails?

I'm not.

I normally use Type F in all my 727 and 904 applications.

I have however used TSC universal hydraulic fluid in one of my 727's. It was a beater car and my trans cooler line broke and its all I had on hand. This was a transmission that had been, and was continually beat on. The universal fluid worked perfect for the next 5 years. I then sold the car to a gentleman that pulled the motor and trans and dropped it into his 3/4 ton work van, and he drove it without incident for the next 6 years before he sold it. That van might still be going strong.

I dont think the 727 is concerned about using a specific fluid.

People keep saying that because it's true. I have built a couple of hundred transmissions in my time. So it's not like I'm guessing at this.

Once again, this thread illustrates the value or not of anecdotal experiences.

Engine oil

Blondes , Brunettes or Red Heads

Walmart house brand Dex/Merc HERE was my choice of fluid when I still had older stuff that used it.

And it's like the proverbial train wreck, you can't help but look.



Tim

Ok, it's a dog-pile so I'll jump in. I've always believed you shouldn't mix transmission fluids. I believe that a blend of type F + at least the older Dextron would cause foaming.

Side note - Someone could run [u][/u]completely type F if you drained the converter and everything + type F has a little higher friction to help older transmission shift better & drag cars to shift harder + I think B&M's "Quick Shift" stuff is type F with blue dye.

To the original poster, a very reputable transmission shop owners showed me a technical bulletin from Shell Oil. It said that if you hadn't changed your transmission fluid in a long, long time, you should only replace the pan's fluid (maybe half the fluid?) + filter and don't flush the system or do a complete fluid change.

Fluid changes over time and it's solubility changes. Waxes come out of the fluid and start to collect in the transmission which isn't much of a problem with the old fluid in there, but if you put 100% new fluid in the transmission, all these waxes will really come out of solution and start to gum up the small passages inside the transmission. Keeping a good portion of the old fluid in the transmission helps keep these waxes dissolved in the transmission fluid where they do no harm.

All ATF's have foam inhibitors so I ain't buying the foaming from mixing.

The fluid change danger in high-mile transmissions is an ongoing debate and, again, anecdotal experience varies. Some believe that a fresh additive package will dislodge varnish buildup and cause problems while some believe that the abrasive nature of aged fluid prevents clutch/band slippage and fresh fluid, being slipperier, will cause slippage.