small shutter from stop: Limites Slip axle?
Senior Member
Joined: May 1999
Posts: 3,188
Likes: 3
From: Kansas side of the greater KC area
My 05 with 3.55 LS has been doing this lately. Mostly when truck is cold until everything is up to operatimg temps. I 'am planing on getting the fluid changed soon since it has lttle over 100k on the original fluid to see if that resolves my problem.
Technical Article Contributor
Joined: Oct 2007
Posts: 177
Likes: 2
From: Baton Rouge, LA
Thought I would be smart and buy the "best" product available.......so I purchased Royal Purple with the built in modifier. Did the service and the chatter was the same if not worse! I paid $20 a quart for the Royal Purple which everyone says is the best! SO, I brought it back in and drained the Royal Purple and added the Motorcraft modifier with the 75W-90. Now it's running as quiet as a mouse peein on cotton. It actually feels like it is rolling smoother and more freely. Not a bit of chatter or noise when turning. BOO, HISS on the Royal Purple.......save yourself some money and buy the modifier from FORD!
I am planning to add a bottle of the Ford/Motorcraft friction modifier to the Royal Purple in the diff.
Does anyone see a problem with this???
Last edited by duckduke; Sep 14, 2013 at 10:43 PM.
Technical Article Contributor
Joined: Oct 2007
Posts: 177
Likes: 2
From: Baton Rouge, LA
For those finding this older thread I resurrected ...........
Yes..... you can and I did add the Motorcraft Friction Modifier (FM) XL-3 to the Royal Purple. Yes, I did some figure 8's to help coat the LS clutches etc. So far so good but I am on day one. I haven't felt any shutter on initial acceleration like I was feeling. I'm optimistic ... but I have read where others had the same result for a week or so and then the shudder/vibrations started again and many ended up installing with a LS clutch kit.
IMO -- from what I've read on this issue here and other F150 forums:
1-- I would not use Royal Purple in the rear diff. If I had read all of what I've read the past week before I did my diff service, I would simply use the Ford/Motorcraft diff fluid and Ford/Motorcraft Friction Modifier. I have read where a number of people using Royal Purple (with the friction modifier included) in the rear diff, have wound up with the same problem (shudder/vibration upon initial acceleration) and then having to add the Motorcraft FM XL-3. Many have switched back to the Motorcraft diff fluid or some other brand besides Royal Purple, and adding the FM XL-3.
2-- If you add the Motorcraft FM XL-3 to the rear diff and can't get rid of the vibration/shudder on initial acceleration. You have 5 choices.
1) Live with it
2) Try doing a total fluid change with another fluid like the spec Motorcraft diff fluid + Motorcraft FM XL-3 and see if it changes (this is a cheap fix if it works)
3) Sell/trade the truck
4) Get a LS clutch kit put in .... dealership cost is about $1300 from what I've read. I've also read where a number of people have trouble, even under warranty, and are on their 3rd kit before they hit 100,000 miles. I think this is the worst option. If you want to fix the clutches ..... see option 5) below (get rid of them).
5) Best choice IMO - Buy an Eaton Truetrac diff .... current price about $509 online from DTS ..... and get rid of the clutches. Install yourself if you're capable or take it to a drive train specialist or race shop that routinely installs diffs. This will get rid of the LS clutches NOTE: According to several posts I've read online ... Eaton suggests 80w90 Petroleum fluid ONLY (i.e. - no friction modifier)
Just my thoughts .... hope this helps someone down the road!!
For more info search for:
XL-3
Eaton
shudder
Truetrac
Yes..... you can and I did add the Motorcraft Friction Modifier (FM) XL-3 to the Royal Purple. Yes, I did some figure 8's to help coat the LS clutches etc. So far so good but I am on day one. I haven't felt any shutter on initial acceleration like I was feeling. I'm optimistic ... but I have read where others had the same result for a week or so and then the shudder/vibrations started again and many ended up installing with a LS clutch kit.
IMO -- from what I've read on this issue here and other F150 forums:
1-- I would not use Royal Purple in the rear diff. If I had read all of what I've read the past week before I did my diff service, I would simply use the Ford/Motorcraft diff fluid and Ford/Motorcraft Friction Modifier. I have read where a number of people using Royal Purple (with the friction modifier included) in the rear diff, have wound up with the same problem (shudder/vibration upon initial acceleration) and then having to add the Motorcraft FM XL-3. Many have switched back to the Motorcraft diff fluid or some other brand besides Royal Purple, and adding the FM XL-3.
2-- If you add the Motorcraft FM XL-3 to the rear diff and can't get rid of the vibration/shudder on initial acceleration. You have 5 choices.
1) Live with it
2) Try doing a total fluid change with another fluid like the spec Motorcraft diff fluid + Motorcraft FM XL-3 and see if it changes (this is a cheap fix if it works)
3) Sell/trade the truck
4) Get a LS clutch kit put in .... dealership cost is about $1300 from what I've read. I've also read where a number of people have trouble, even under warranty, and are on their 3rd kit before they hit 100,000 miles. I think this is the worst option. If you want to fix the clutches ..... see option 5) below (get rid of them).
5) Best choice IMO - Buy an Eaton Truetrac diff .... current price about $509 online from DTS ..... and get rid of the clutches. Install yourself if you're capable or take it to a drive train specialist or race shop that routinely installs diffs. This will get rid of the LS clutches NOTE: According to several posts I've read online ... Eaton suggests 80w90 Petroleum fluid ONLY (i.e. - no friction modifier)
Just my thoughts .... hope this helps someone down the road!!
For more info search for:
XL-3
Eaton
shudder
Truetrac