Gents -

OK, may seem like a simple question, but I've always used a Dextron type AFT fluid. Still do.

Since I'm not racing any more, is this still the preferred ATF??? Dex, DexII, III, Type-F??? What are you guys using and why?

Also without a full rebuild can these be mixed? Meaning can I add a quart of Type-F to Dex?

Thanks

Archer

 

You can do anything you want to do as long as you are willing to suffer the consequences. (Great, now I sound like my parents )

I've always used the latest Dextron fluid out there (I think its III) in all 727 trannies (its been a few years though). I've heard about people mixing type F and III to get by if they had a leak but would flush the system out afterwards with III or synthetic after fixing the issue.

As of right now though, I use synthetic in my DD/Tow rig and will probably have the wife's car flushed with synthetic fluid too. It seems to not break down as fast as normal fluid, the fluid carries particles to the filters better, the trans fluid temps is a little cooler and the trannies seem to last longer (IMO - of course driving style plays a HUGE factor in that).

 

Drain it and replace it with ATF 4 full synthetic.

 

or dextron 3

 

OK guys -

Which can be safely mixed, and why can't the ones that can't, can't? (I'm assuming a sludge situation?)

BTW - We're not talking about a stock tranny. It's a beefed up 727 with a manual valve body and a 3K stall converter, if that makes a difference.

Archer

Archer

 

To the best of my knowledge ATF4 is the only synthetic.. All the others are hybrids or base stock with multiple additives to enhance or retard the friction requirements. Type F can be a band-aid for slippage but was NOT designed for the 727. Its "off label" use. Dextron can cure harshness as it allows slippage.

The 46RE and RH used in all the 2500HD trucks are nothing more than the 727 with a cassette based OD attached to the back. Same pan, same filter and gasket. These transmissions all use ATF4. Dextron or Type F will work. But at serious loss of transmission life.

If its a used 727 with no service life or history I would use what the manual requires. Synthetic wont undo anything and the price point is silly money. But if its a rebuilt box I would use ATF4.

 

Guys -

Thanks for the info.

Let me see if I can make it a little clearer. The tranny was rebuilt a few years ago. I can't contact the guy who rebuilt it, and all I down is that he used a "Dextron" type fluid. (Which was all I used in the past.) So the real question is that without a full flush (and "full" is optimistic") can I add any "Dextron" into the mix and what would be my best choice?

Thanks,

Archer

 

Since history is unclear, I would drop pan and drain and fill the entire case with ATF3. Forgive me on the numbers but the mopar trans fluid use to be called 7176 ( a little help here from those with the better memories than I ) and then was rated A, B, C, D and E. So 7176E is ATF3. Much cheaper than ATF4 and you CAN use it and Chrysler recommends ATF3 for the 727. The ATF4 just keeps that anti shudder characteristic up to and past the warranty period of 100K on the new stuff.

I wouldn't use the Dextron as it is a GM product but some have posted above that it works well.. I have no TSBs or cross reference data that says it can be used safely.

Wish there was a "yes or no" for you but I dont like to say "no" when others have had good success with the different fluids.

 

atf 3 or 4 is way overkill in a stock 727

 

ATF 3 has been phased out for ATF 4 I used to run a modified 727 with F type B&M fluid. DO NOT HAVE YOUR TRANS FLUSHED !!!!! Flushing can do more harm than good sometimes !!!! Drop the pan and change the fluid & filter !!!!!!
Look in the old service manuals they called for dextron fluid

 

Gents -

Unfortunately, what I'm hearing is that people have used just about anything and everything with both good and not-so-good results. Kinda why I posed the question in the first place.

TV -

That was my concerned about a flush. Yes, that's why I always used Dextron.

Moparted -

Seriously doubt there's anything stock in the tranny, except for the case.

Basically right now, I'm 1/2 quart low and wanted to know what's safe to top it off with.

Next time I drain it, will probably go with ATF-4.

Thanks

Archer

 

MY LOCAL BUILDER SAYS NO WAY TO ANY ATF plus in 727s or 904s

 

m -

And does he have a specific reason for saying that, or rather any specific evidence?

Not trying to start a argument, but when there are 2 opposing views in any debate, the reality is usually somewhere in the middle.

Archer

 

Everyone has an opinon. That's why two sides. I run ATF 4 in my professionally built 727 with manual valve body. It will smoke the tires at 55 mph in second gear.

 

Makes me wonder about that BUILDER???

 

I found this at http://www.allpar.com, at least i think i did been reading so much lately things kinda get blurry.



When you change your transmission fluid, always use the recommended fluid. (1989-91 owners, ignore the manual and use ATF+4).

Don't assume your mechanic or dealer knows what fluid to use. Ask them to make sure. (Some people recommend watching the mechanic pour it in. We have been told about mechanics who said they were using ATF+4 when they were not.)

All Chrysler (and Honda and Toyota) four-speed and six-speed automatic transmissions* are very sensitive to the quality of the transmission fluid. Only use ATF+4 in these transmissions. Do not use Dexron or Mercon.

Some companies sell "universal" fluids; if they state that they are compatible with ATF+4®, they should work, and can be helpful for those unsure of which fluid to use. The Center for Quality Assurance warned us to check the label for Chrysler’s license number, and to make sure the fluid is on their list of ATF+4® licensed and tested fluids.

When i think about it, my work van went through two tranies over a 8 yr period the thing i noticed about them when dissemble is dirt and hard seals the tranies hated the stop and go traffic when its hot i always run a large cooler i bypass the radiator altogether
when they would get hot they would slip out of gear while stopped in traffic/light, and would clunk back into 1st and shift fine i would check my fluid always full but i would notice the fluid getting dirty real fast /brown smelled fine just looked burnt when i would change the fluid / filter more than normal in the summer months
i wonder if this dex 3 is the issue?
i'm using atf+ 4 in this 518 now but its got some miles on it with dex 3 not many but at least 2000
and its a few months to summer here so i wont get it in the heat for awhile to test this theory.
i read ab article a long timeago exsplaining the variables on all the trany fluids it covered:
detergents
viscosity
temp range
flash point
benefits/drawbacks too, seal's O-rings, clutch material, and the hard parts.
what i'm remembering may be the issue with my fore mentioned trany symptoms?
the f type had greatest heat range/viscosity but to much detergent
the dex had a lower temp/viscosity range which caused internal wear not quite enough detergent

well i will keep an extra eye on her for good measure