The Diesel Garage banner

1 - 8 of 8 Posts

·
Senior Member
Joined
·
750 Posts
Discussion Starter #1
what oil goes in the 6 speed I have an 02 6 speed 7.3 and a 08 6 speed 6.4
 

·
Junior Member
Joined
·
42 Posts
It calls for mercon fluid which has been replaced by mercon V per a tsb, however Im running pennzoils version of the gm synchromesh in mine for the last 100,000 miles (flushed twice now) and It seems to shift smoother. You may also want to get one of those automatic transmission cooler flush kits and flush the cooler lines. When I did mine all kinds of nasty stuff came out the first time.
 

·
Junior Member
Joined
·
10 Posts
I use Mobile 1 ATF in mine and no problems.
 

·
Haulin' Hay
Joined
·
565 Posts
When you say 6 speed, and 7.3 -- Are you referring to the ZF manual trans?? If so, that would need Gear Oil, and not ATF.
 

·
Junior Member
Joined
·
10 Posts
When you say 6 speed, and 7.3 -- Are you referring to the ZF manual trans?? If so, that would need Gear Oil, and not ATF.
Incorrect. The ZF6 Transmissions (at least in the 99-02) take synthetic ATF, not gear oil. Although I read somewhere that the later ZF6's (08-10) use a different lubricating oil.
 
  • Like
Reactions: NCfarmboy

·
Senior Member
Joined
·
1,700 Posts
Nope. It's ATF (for the 02)
gear lube for the 08 (GL4)
ATF throughout the ZF lineage 5 or 6spd, I think it was 08 or so that they started specifying the use of Synthetic and/or regular Merc-V (synthetic for diesel, reg merc v for gasser), but I dont ever recall GL4 or any other type of gear lube. The ZF's have little needle bearings that wont lube well with heavy oil.
 
1 - 8 of 8 Posts
Top