Mixing ATF+4 with regular ATF?

Posted By: RMCHRGR

Mixing ATF+4 with regular ATF? - 01/14/14 10:14 PM

I know this gets beaten to death and there are many varying opinions on ATF+4 but I'm gonna ask anyway because after all I've read through, I don't have a clear answer. Maybe there ins't one?

I've read so many different things about using ATF+4 in older TFs that it can get confusing - shifts are not as hard, formulated for newer lockup transmissions, may cause leaks due to different additives/detergents forming acids, the world will end yada yada.

My trans is a 904/999, Turbo Action forward manual valve body, (No LBA), 5 disc drum, low gear set etc. Nothing fancy. I changed the pan this winter and used a new silicone gasket. I did not drain the converter. Unit looked clean, fluid was clean. Previous owner said he ran Dexron in it. It shifts pretty hard but relatively smoothly at WOT. It's good.

Here's the thing - I have a case of ATF+4 on my shelf. What happens if I add the ATF+4 to my trans? Will I blow it up or will I not notice anything? Will it cause leaks?

Please advise.

- Greg

Posted By: Thumperdart

Re: Mixing ATF+4 with regular ATF? - 01/14/14 10:23 PM

I`ve always ran type-F till recently where Wally world only had ATF+4 so been running that w/about 10 passes at the track and a few hundred street miles and all seems fine and fluid looks/smells new............

Posted By: dusturbd340W5

Re: Mixing ATF+4 with regular ATF? - 01/15/14 12:17 AM

It will not hurt anything, can change shift feel because of the different friction modifiers that are it the +4.
Will not cause any leaks the 904/999 uses the same rubber and seals as the 500od unit.
That being said I personally wouldn't use it in a race application.

Posted By: VernMotor

Re: Mixing ATF+4 with regular ATF? - 01/15/14 01:13 AM

I run +4 in my car and have mixed with +3 many times

Posted By: jcc

Re: Mixing ATF+4 with regular ATF? - 01/15/14 04:15 AM

Quote:

I know this gets beaten to death and there are many varying opinions on ATF+4 but I'm gonna ask anyway because after all I've read through, I don't have a clear answer. Maybe there ins't one?

I've read so many different things about using ATF+4 in older TFs that it can get confusing - shifts are not as hard, formulated for newer lockup transmissions, may cause leaks due to different additives/detergents forming acids, the world will end yada yada.

My trans is a 904/999, Turbo Action forward manual valve body, (No LBA), 5 disc drum, low gear set etc. Nothing fancy. I changed the pan this winter and used a new silicone gasket. I did not drain the converter. Unit looked clean, fluid was clean. Previous owner said he ran Dexron in it. It shifts pretty hard but relatively smoothly at WOT. It's good.

Here's the thing - I have a case of ATF+4 on my shelf. What happens if I add the ATF+4 to my trans? Will I blow it up or will I not notice anything? Will it cause leaks?

Please advise.

- Greg

I haven't a clue, but I like your style.

Posted By: 383man

Re: Mixing ATF+4 with regular ATF? - 01/15/14 06:17 AM

Thats all my brother and I ever use. We both worked at Dodge dealers most of our life and we both did auto trans work so we have a fair amount of ATF+4 laying around as we got a few spare qts on some warranty jobs.

The trans in my sons Dart has only had the ATF+3 and 4 as its been in his Dart since 1996 and it never been out just serviced a few times in the car which was filter and fluid changes. Ron

Posted By: Guitar Jones

Re: Mixing ATF+4 with regular ATF? - 01/15/14 03:55 PM

I agree, it won't be a problem. Heck I use Hyundai SPF III in mine because I have so much of it.

Posted By: RMCHRGR

Re: Mixing ATF+4 with regular ATF? - 01/15/14 09:08 PM

Cool, thanks guys. Seems like it won't be an issue. Just wanted to be sure before I dump it in. Again, I didn't remove the unit to drain the converter.

yeah, I was a Chrysler and Hyundai tech myself, that's why I have the +4. I've used Hyundai fluid in other vehicles too.

Posted By: Sammy

Re: Mixing ATF+4 with regular ATF? - 01/15/14 09:44 PM

Goldman out of Allentown Pa. does my transmissions and told me that ATF+4 is the best for 727's and 904's.
You can run it all year long and your transmission fluid will look like new.Clutches and steels look mint too.

Posted By: dusturbd340W5

Re: Mixing ATF+4 with regular ATF? - 01/15/14 11:38 PM

Quote:

Goldman out of Allentown Pa. does my transmissions and told me that ATF+4 is the best for 727's and 904's.
You can run it all year long and your transmission fluid will look like new.Clutches and steels look mint too.

build the unit correctly and you can use any fluid all year and it will look like new.