What are you all using for fluid in your ZF5?

 

Auto tranny fluid.

 

I use Mercon automatic Transmission Fluid.

I was told by the Ford rep back in 1991 when I purchased my truck that the ZF-5 has such close tollerances that ATF was used because gear lube would be squished out of the gears leaving them dry. He also said that the ATF should be changed regulary because any dirt accumulation would be ground into the gears causing big problems.

I don't know how correct he was, but I change both my transmission (ZF-5) and transfer case every 50,000 miles and have never had a problem, 260,000 miles and still going strong. (note- For about 10 years I used to haul several 2-ton loads each week and still carry a 3,500 truck camper 5-6 times a year.)

 

ATF is the oil too use.... I have 350,000k on my truck.

But with the notorious noise the ZF makes... specially with the SMF conversion... some have used synthetic engine oil (10w30 I think), just to try too quiet it down a bit... mine sounds very similar to a concrete mixer in the first couple of gears...lol. I think I'm going to try it out next oil change and see if it makes a difference.

 

I think they are using 5w30.

-Enjoy
fh : )_~

 

Ya Im running ATF, I heard of running 5w30 but didnt know if it was just hear say or if anyone really was doing it. You recommend doing it even if I have not done the SMF conversion?

 

I used RP ATF in the ZF I put in my 85 F-250, and it was only a little noisy in neutral with 160k miles. I need to change the fluid in my 93 now.

 

I am running the Royal Purple (full synthetic) ATF in mine. Changed about 30k ago, and no problems yet. Seems to shift a little smoother too.

 

The only reason I want to use synthetic engine oil is because my tranny is too noisy for my liking. I believe atf is rated at 20w and from what I have read using a thicker oil can quiet it down a bit... hence the use of synthetic engine oil.

These tranny's were designed for atf and using any fluid other than that would be a gamble IMHO... People have used synthetic engine oil and I will surly give it a try but I know it's at my own risk... I'm just willing to take it cause I can't stand the noise and in reality my tranny prolly wont last too much longer anyhow with the miles it has....

So my advice would be to use atf... or upgrade to synthetic atf... if you think your tranny's too loud and you want to gamble then use a thicker synthetic engine oil, it has been done... but I doubt some one will recommend it solid flywheel conversion or not.

hope that helps....