Thread: Quest about rear diff shudder

Originally Posted by exploreco

Thought I would start a new thread. Being new to truck driving and ownership I need some advice. As I posted in my other thread I purchased a 2010 screw lsl 3.73 (I will get my sig updated soon ). Anyway, on the test drive the truck drove perfect. Got home about an hour away and noticed some chattering in the rear end when turn either direction from a stop. Also sounded like a light whining noises but truck driving is new so getting used to different sounds lol. Anyways, used car sales manager called me back and told me what I am feeling is just the ls kicking in and they had thourghly looked the truck over abd they don't feel anything is wrong with the truck but if I was not happy with it they would let me bring it back. My wife and I really like the truck and is in such nice shape and we want to keep it. Can one of you truck experts help me understand if this could be a serious issue or not? I have read numerous things on the internet about clutch packs being bad or maybe just needing to change the gear oil in the rear diff. I don't know when that was last done. Should I start with changing the fluid in the rear diff? How much does a rebuild cost? Should I be worried? We really want to keep this truck. I appreciate the guidance greatly! Sent from my Samsung Galaxy S4 using Tapatalk

I'd get the gear oil changed. Then get a bottle of MotorCraft Friction Modifier and put in it. If it doesn't fix it then a rebuild would be needed.

Originally Posted by Ford Fan#1

I'd get the gear oil changed. Then get a bottle of MotorCraft Friction Modifier and put in it. If it doesn't fix it then a rebuild would be needed.

No the whole bottle. Listen. First off. Welcome. Try to ask the dealer if they did anything to the rear. If you are hearing a whine. It sound like the pinion gear. If u hear a whine it actually sounds like it's to tight. I had a prob with my 03. It was to tight. Wound up ruining the ring and pinion and had to have the rear re miked so it all fit nice and snug again. I would take it to a credible shop and find out what your options r. Good luck. If u lived closer I'd take it for a ride and check u out myself. But it's kinda hard without hearing it lol

5Star tuned.....

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Originally Posted by Ford Fan#1

I'd get the gear oil changed. Then get a bottle of MotorCraft Friction Modifier and put in it. If it doesn't fix it then a rebuild would be needed.

It's only a few ounces of limdiff oil. Not a whole bottle. If you had a Haynes manual dr procrastinater you would know that.

5Star tuned.....

Originally Posted by Jersey_Joe

No the whole bottle. Listen. First off. Welcome. Try to ask the dealer if they did anything to the rear. If you are hearing a whine. It sound like the pinion gear. If u hear a whine it actually sounds like it's to tight. I had a prob with my 03. It was to tight. Wound up ruining the ring and pinion and had to have the rear re miked so it all fit nice and snug again. I would take it to a credible shop and find out what your options r. Good luck. If u lived closer I'd take it for a ride and check u out myself. But it's kinda hard without hearing it lol 5Star tuned..... ---------- It's only a few ounces of limdiff oil. Not a whole bottle. If you had a Haynes manual dr procrastinater you would know that. 5Star tuned.....

I've heard more the merrier basically lmao. And I would have got it today but I didn't have enough money with me.

Originally Posted by Ford Fan#1

I've heard more the merrier basically lmao. And I would have got it today but I didn't have enough money with me.

The more the merrier? False. Get your facts from a book. Or a service adviser. Not some dude who fixes stuff and has an opinion on how to fix things.

5Star tuned.....

No fair with the double standard crap Joe.

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Originally Posted by Jersey_Joe

It's only a few ounces of limdiff oil. Not a whole bottle. ..

It is the whole bottle. Ford Motorcraft OEM XL3 Friction Modifier Additive 4oz

Good job Adam