Slight jolt when letting off brakes during take off / Auto transmission

[Tdifonzo]

I just started noticing a slight jolt when taking off from a stop a couple weeks ago. It happens about 50% of the time and it feels like the transmission is shifting for whatever reason and almost feels like the Auto Start/Stop but it's not it and even happens when that is turned off. I really only feel it in the brake pedal. Has anybody else experience anything like this?

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[Ksjrb03]

All the time or after cold startup? Mine has always done it, until warmed up. The rpms are crazy high until it’s up to temp.

 

[Tdifonzo]

All the time or after cold startup? Mine has always done it, until warmed up. The rpms are crazy high until it’s up to temp.

I'm pretty sure it happens no matter the engine temp but I will double check.

 

[Techun]

I occasionally feel a slight jolt/rough shift when coming to a stop. Haven't noticed it from a start.

Maybe it's suspension movement? You were nose down when braking and starting up you're nose up..

 

[ksh]

Actually learned about this at the off-roadeo event, but here's a video explaining (what I think is happening with yours) what they talked about.

 

[AceGoliath]

Sounds similar to this?

https://www.bronco6g.com/forum/threads/front-suspension-“thump”-noise-feel.46338/

 

[Tdifonzo]

Actually learned about this at the off-roadeo event, but here's a video explaining (what I think is happening with yours) what they talked about.

Good advice but I've never parked without the parking brake in any of my cars. Will send this video to my girlfriend though who refuses to use it. Lol

 

[dgorsett]

Good advice but I've never parked without the parking brake in any of my cars. Will send this video to my girlfriend though who refuses to use it. Lol

Well, I'm team GF, but whatever. I only use Parking Brakes on hills, when I'm leaving the engine running or on really steep hills otherwise, manual or auto, but that's just me. Never broken or worn out parking pawl, or any other transmission component in 50 years of driving (not counting my old '55 Willys with a Ford 289 that ate T90's).

To your original question my 2.3 kinda 'stutters' at brake release sometimes, like the ASS is working but I have it shut off. I have no clue what it is...

 

[Dubsesd]

I think I may be experiencing the same issue…. Does the thump almost feel like someone tapped your bumper from behind? It’s quite annoying to me because I think something is wrong and not right. Almost like the driveshaft has play in it. Very hard to explain.

 

[Overboost]

It’s most likely the slip yoke in the driveshaft that is sticking. Have your dealership lubricant the splines with the Ford PTFE lubricant.

 

[Brockdog12]

I have this issue, I believe it is the rear brakes, like the hill brake assist is activating and releasing when you take off the brakes. I have been releasing the brakes and not holding them and rolling slightly and it seems to not happen if I do that. Still playing around with it. Could also be the differential.

 

[4xFord]

I just started noticing a slight jolt when taking off from a stop a couple weeks ago. It happens about 50% of the time and it feels like the transmission is shifting for whatever reason and almost feels like the Auto Start/Stop but it's not it and even happens when that is turned off. I really only feel it in the brake pedal. Has anybody else experience anything like this?

I have only recently started noticing this and I'm at 8,400 miles. Like you said, I feel it in the pedal as I take off and my auto start/stop is disabled.

I'm hoping it's a brake vacuum/ABS quirk and not that the transmission is shifting as soon as I hit the gas. I guess time will tell but for now I'm going with an observation and not a concern.

 

[Ducati1098]

It’s most likely the slip yoke in the driveshaft that is sticking. Have your dealership lubricant the splines with the Ford PTFE lubricant.

The bronco driveshaft doesn’t have a slip yoke

 

[Overboost]

The bronco driveshaft doesn’t have a slip yoke

There has to be some place in the drive line to deal with the fore/aft movement of the driveshaft as the rear axle wraps up. Mine is in the middle, but doesn’t appear serviceable.

 

[Bonnie6G]

I’ve noticed this a couple of times as well. Cold and warm engine. Last one was at a stop sign about to pull out into the intersection and as I was releasing the brake pedal it jolted forward like I was tapped on the rear bumper. Didn’t get it again the rest of the ride home. I have no idea what would cause this. Maybe something with the electronic brakes controls?

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