I just had my transmission gone through by a seemingly reputable shop. They only do manual transmissions and they came recommended by a local Powerstroke tune shop.

They took the time to put IN WRITING that they recommend using 10W30 full synthetic in my ZF6. He proclaimed that ATF is too thin.

Being that they put it in writing and are warranting their work... I am inclined to try this but I wanted to run it past you guys... Has anyone ever heard of this?

 

No, but I would run what they tell you till the warranty is out. By then you should no.

 

Seems like it would be worth a shot. Especially with a warranty. Care to be our Guinea pig?

 

I would recommend any GL5 rated multi viscosity 75/90. In SEVERE duty, used predominantly (> 75%) for towing I would use the 75/140.

ATF is designed for Automatic Transmissions. Different from a Gear Mesh Transmission.

See what Amzoil and others say in their testing data. I have no idea other than what I do for AT and MT.

 

I've been using Syn ATF for 18 years. No reason to change now.

 

Hey pirch, these granny are not a "bath" type slushbox. There's a pump in there. No way would I run that thick of crap. I'm with FATS, but I run conventional mercV

 

This says a lot. I had no idea. Thanks for the info!

 

Pirsch, I think ya misread? He's talking about motor oil in the transmission, not motor oil or ATF for the diff.

Stewart

 

I would never run anything other than ATF in the ZF6 since it has an internal pump and cf synchros.

 

Picked it up today. I had them fill it with the synthetic 10w30. I'm on a new clutch so am taking it easy for the break in period however the truck shifts a lot better.

I also have no good reference for shifting because up until today, I have only driven it with a transmission that was half full of coolant.

I'll update as I drive it along...

 

One week and 400 miles later... still shifts great. I'll update again once I have a trans temp sensor working and run that for a while.