Diagnosing? Light shudder (anyone have this)?

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SCSVT

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2012 Raptor, 92k miles and 100% stock. Bought the truck 3k miles ago, and just noticed this starting:

When sitting at a red light, if you ease partly off the brake to roll forward (still a little resistance on the brakes) the truck shudders, like an up and down motion in the rear end as it eases forward. It's a very rapid shudder.

The same occurs if you are sitting at a light with a slight uphill incline.... if you lift 100% OFF the brake and let it roll forward. No other shudders on acceleration. It's just when easing forward at say 1mph.

The truck has 92k, never had trans fluid changed

Any thoughts?
 

MFNG

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2012 Raptor, 92k miles and 100% stock. Bought the truck 3k miles ago, and just noticed this starting:

When sitting at a red light, if you ease partly off the brake to roll forward (still a little resistance on the brakes) the truck shudders, like an up and down motion in the rear end as it eases forward. It's a very rapid shudder.

The same occurs if you are sitting at a light with a slight uphill incline.... if you lift 100% OFF the brake and let it roll forward. No other shudders on acceleration. It's just when easing forward at say 1mph.

The truck has 92k, never had trans fluid changed

Any thoughts?
I’ve had a similar experience on my 2014; got it at 93k, 120k now. I have the same on my 09 Edge.

I think it’s a Ford thing somehow. They don’t like to idle or roll slow. I always seem to have it in both vehicles when easing into acceleration from a stop or just idling through a parking lot without any throttle.

I’ve found that if you just give it a little more gas from the start you won’t get that.

Someone else may have a more technical answer. Help us!
 

CoronaRaptor

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One possibility is your rear calipers are sticking and not releasing your rear brakes! Might be time to check those calipers and brakes.
I'm thinking this as well, or the rear axle seals are leaking, etc. Or whoever did the last brake job might have screwed up, lol. Check and lube the emergency brake cables, etc, have to pull the rotors to fully check whats going on, or jack up the back of the truck with a buddy around, put on the brakes and release and see if there is binding when spinning the tires by hand.
 
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SCSVT

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I’d start with changing the transmission fluid. Clutch material particles, moisture intrusion, and additive package breakdown can all contribute shudder issues.
I’ve heard concerns over changing trans fluid at high mileage, hate to do that if I can’t verify it was done at least once in the trucks 90k life… unsure
 

FordTechOne

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I’ve heard concerns over changing trans fluid at high mileage, hate to do that if I can’t verify it was done at least once in the trucks 90k life… unsure
Yes, that can be a concern on high mileage vehicles. The transmission fluid replacement interval on these trucks is 150k, so you should be fine.
 

SJC8713

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i have the same. It just a lurch forward shudder but only when almost completely stopped or just letting off like in a starbucks drive thru.

Ive checked my brakes, replaced the rotors and calipers and e brake cable and it all works fine as designed. I've just learned to live with it.
 
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