Which gear oil to use?
Thread Starter
3rd Gear Member
Joined: Sep 2007
Posts: 734
From: Sacramento, CA
Which gear oil to use?
So this weekend I am switching to 4.10s. Which gear oil weight should I put in? I am just going to get royal purple. Its like 10 dollars a quart I think. I need to buy 3 and put 2.5 in right? Also it doesnt need friction modifier does it?
4th Gear Member
Joined: May 2006
Posts: 1,157
From:
4th Gear Member
Joined: Oct 2007
Posts: 1,778
From: Harrisburg PA
The weight is: 75W140. Yes get 3 quarts.
I put the Motorcraft Synthetic in and it did require Friction Modifier. I purchased from the Dealer and cussed them out all the way home, the criminals charged me $22 per quart. Wont do that again.
I put the Motorcraft Synthetic in and it did require Friction Modifier. I purchased from the Dealer and cussed them out all the way home, the criminals charged me $22 per quart. Wont do that again.
2nd Gear Member
Joined: Aug 2006
Posts: 159
From: CT
Oh, but I guess you mean when you swap in a new gear set. Yeah, makes sense. Your supposed to change the oil after break-in period so why put the expensive stuff in...
Last edited by doctorstrobe; Sep 18, 2008 at 04:07 PM. Reason: I'm stupid.
3rd Gear Member
Joined: Nov 2006
Posts: 825
From: NJ
When I went 3.73's, my shop put in 2 qts Royal Purple 75/140 synthetic, and 1 bottle of Ford friction modifier. ($13.95 each for the RP, and $4.95 for the Ford FM)
Are you really supposed to use 3 qts??? Now I'm concerned, I had the swap done back in June, I've put on 3,500 miles since then, and now I'm noticing a slight noise on accel & decel at about 60 mph!!! I'm getting a little pissed...I also remember him not using the gear install kit, unless he had one laying around and didn't charge me! (Doubt it)
Are you really supposed to use 3 qts??? Now I'm concerned, I had the swap done back in June, I've put on 3,500 miles since then, and now I'm noticing a slight noise on accel & decel at about 60 mph!!! I'm getting a little pissed...I also remember him not using the gear install kit, unless he had one laying around and didn't charge me! (Doubt it)
Last edited by JimsGT; Sep 18, 2008 at 04:36 PM.
Cut & Paste Expert
Joined: May 2007
Posts: 13,322
From: NW Arkansas
Synthetic diff lube like factory and friction modifer.
S197 8.8 SPECS
Seems to me that I read a TSB about filling it all the way up to
the fill hole until it starts coming back out instead of the original
1" below the fill hole recommendation.
S197 8.8 SPECS
Seems to me that I read a TSB about filling it all the way up to
the fill hole until it starts coming back out instead of the original
1" below the fill hole recommendation.
Last edited by 157dB; Sep 19, 2008 at 09:42 AM.
4th Gear Member
Joined: May 2007
Posts: 1,249
From: Utah
My installer used Royal Purple that had the friction modifier in too. But my clutch packs still moaned during slow turns. So I waited...broke the gears in by just driving around like granny..went through a few heat cycles and good to go. Drove for another 2 weeks, getting in a good wear pattern, then off to the dealer for new clutch pack and new gear oil, all under warranty. Worked out kinda sweet.
Thread Starter
3rd Gear Member
Joined: Sep 2007
Posts: 734
From: Sacramento, CA
The royal purple stuff has friction modifier in it. I think I am going to be running 85w140 or whatever it is. My friend is running that too cause he talked to ford and they said unless you are in a cold area you can run a higher weight. I am not sure if this all sounds right... what do you guys think?
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