Gear Oil? (I know)

[gmantheman]

I went off the recommendation of a local shop that specializes in gears and they recommend dino oil for gears. In a local forum another mustang shop owner specialist says to used synthetic because of the clutch packs. So, should I be using synthectic because of the clutch packs?

 

[bolted3v]

yes.

i used royal purple 75-90wight IIRC and 1 bottle of ford motorcraft friction modifier

 

[Riptide]

Depending on the brand/type of gear oil you don't need the friction modifier either. I know the valvoline synthetic stuff states as much in their documentation.

 

[DirtyDogOfTheDesert]

I know the valvoline synthetic stuff states as much in their documentation.

So does the Royal Purple.

 

[Dread53]

I've had Royal Purple (without modifier) in the back end of mine for the last 35K miles and it's a beautiful thing.

 

[mrdeath2000]

the sticker on the diff cover says "Synthetic Only".
I use 75w140 RP (with modifier already in it), but I also live in Phx, AZ where it gets MFN Hot!

 

[gmantheman]

I am using friction modifier

 

[Wicked97]

If you read the royal purple bottle it has the fiction modifier already added.

you guys are just adding double.... wasting money

 

[JeremyH]

Manual calls for synthetic only.

 

[GrnBullitt08]

75-140 Royal Purple

 

[Embalmer]

75-140 Royal Purple

Exactly the same in my new rear.

 

[JPO8GT]

synthetic all the way for Ford Trac-Loc

 

[rayS197]

Manual calls for synthetic only.

exactly. 75-140.

 

[bolted3v]

If you read the royal purple bottle it has the fiction modifier already added.

you guys are just adding double.... wasting money

i know it says "it has it there" already but i still put a little bottle there anyways. 5 bucks aint shit anyways

 

[CandyRedGT]

I had Royal Purple in my car...till i blew the stock posi.....When i put the True Trac in it......they reccomended NO synthetic ever in it.

 

[JPO8GT]

I had Royal Purple in my car...till i blew the stock posi.....When i put the True Trac in it......they reccomended NO synthetic ever in it.

Same here changed from stock trac loc to eaton/detroit trutrac Plain 80w 90 lucas

 

[bronxbomba63]

i know it says "it has it there" already but i still put a little bottle there anyways. 5 bucks aint shit anyways

+1 I added a bottle of friction modifier when I had my 4.10's installed. I also used RP. Personally, I think the little bit extra helps me sleep a little better and worry less.

 

[Thereaper]

Put Amsoil in it.

 

[GT E UPP]

For me it's always been Royal Purplle 75-140 with a bottle of friction modifier.
Better to have all the protection possible for the sake of an extra $5.00....

 

[gmantheman]

This is the response I got from the shop: When sythetics are used, the friction modifier tends to fall out of the solution quickly. Use regular gear oil. Name brands, good quality. Remember this shop specializes in Gears and Axles.