Synthetic vrs reg gear oil on a new rebuild?

[oldtexasdog]

I am doing a rear gear change this weekend on a 08 GT to FRPP 4:11s. Which is better synthetic or reg gear oil and why? Also what would be a good modifier to use?
Thanks all for your time and input.

 

[ct07gt]

Try 75W-140 with Additive friction modifier XL-3. From the research I have seen, some people recommend synthetic, some say to go with conventional. See if your owner's manual recommends anything.

 

[oldtexasdog]

Try 75W-140 with Additive friction modifier XL-3

So reg oil 75W-140 and the XL-3? I get that at the Ford house?

 

[oldtexasdog]

Try 75W-140 with Additive friction modifier XL-3. From the research I have seen, some people recommend synthetic, some say to go with conventional. See if your owner's manual recommends anything.

Thanks for the info. It was SPOT on!!

 

[Rocket3005]

I Would Go With Redline Synthetic

 

[ct07gt]

No problem, good luck with the install. I would love to do a differential upgrade and gear change, but can't really spend the money right now. Let us know how everything goes.

 

[Big Large]

ford specs synthetic only in the rears. its even stamped on the tag on the cover. use only synthetic.