Rear end shudder

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Jul 31, 2015 | 07:06 AM

ClinchValleySD

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From: Clinton, TN

Rear end shudder

Hello all in Ford Truck Land
The 2004 SD that I've had now for about six weeks seems to be doing really well, after spending some bucks on wear items. It's doing something, however, that reminds me of a TractionLok that I had built for the '67 Fairlane: rear end shudders in slow turns or pulling one of the curvy roads up the ridges around here. Could I be on the right track with this idea? Haven't checked if it's a LS diff yet.
Thanks...
-Jon

Jul 31, 2015 | 08:58 AM

r2millers

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From: Southern Cal

Yep, sounds like a LS rear end.
I'd drain and refill with the approp, gear oil and add friction modifier.

Jul 31, 2015 | 09:05 AM

ClinchValleySD

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From: Clinton, TN

Thanks. Just happened to remember that the other day, that one would make the whole car shake! Had some friction modifier put in when I had an oil change a couple of weeks ago, but prolly does need new lube with another shot of FM. One of the items on the list!
Jon

Jul 31, 2015 | 09:22 AM

r2millers

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From: Southern Cal

Doesn't sound like it but the tranny can shutter too. Normally it's when shifting up, into overdrive, and not necessarily when turning.
Kinda feels like running over Bots Dots when approaching an isolated stop sign.
I'd start with the new gear oil and modifier.
Good luck.

Jul 31, 2015 | 09:42 AM

ClinchValleySD

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From: Clinton, TN

Yeah, I have a friend who had a '94 F-150 that would do that. This is turning slowly, like in a parking lot. Looks like somebody may have been into it (rebuild?), so that is on the to-do list. Along with the trans, coolant, and other good stuff.
Thanks again!
Jon

Jul 31, 2015 | 12:13 PM

droldsmorland

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From: Land of Taxes

After the fluid refill with modifier do a few figure 8s so the new fluid gets into the clutches. Takes longer to get in there if you dont.

Jul 31, 2015 | 02:55 PM

SteveH-CO

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Joined: Jul 2005

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From: Southern Colorado

My truck shuddered on takeoffs (especially slightly angled takeoffs) and I found that the rear-most u-joint was shot. Replacing that, and lubing the splines with the PTFE Ford lube transformed my truck to feeling 'like new' on takeoff.