Feels like I got hit in the REAR when I brake

[Meccanoble]

When I brake hard, I feel a slight delay reaction where it feels like I got hit in the back or like the rest of my car just caught up or something. I'll check the motor mounts again but it feels like its coming from rear. Any suggestions on what to look for?

 

[Jaytizzle]

I have the same issue.

Does your RPM jump up a little as well and then go back down?

 

[Meccanoble]

I'll test and update you

 

[Doubeleive]

well first thing I would check is the brakes/brake pads

 

[intheburbs]

Slack in the drivetrain? Maybe a bad U-joint?

 

[Meccanoble]

I just changed all 4 brake pads at the same time 2 weeks ago but this has been happening before that. I am wondering about the U-joint. I have a slow leak of tranny fluid and I seen a video where someone showed it coming from U joint but because of angle, it drips near oil pan giving the idea its oil pan leak when it isnt. Looking up some videos to test the U joint. I never drive in anything other than 2WD nowadays. I always thought its impact would be when in Auto or 4WD.

I'm not sure what slack in the drivetrain would be. Bad tranny mount?

 

[intheburbs]

The torque converter locking or unlocking strangely could also cause what feels like slack. Kind of like that oscillation you can set up if you lay off the gas quickly in a low gear on a manual transmission vehicle.

Those would be my first two culprits - U joints or torque converter.

 

[Meccanoble]

Yes my rpm's definitely jump. I took a video where I braked hard twice and seen the rpm's jump a little. This doesnt happen under normal braking, only hard braking. New torque converter needed?

 

[gpracer1]

Put it neutral and brake hard see if its still there....maybe its a harsh downshift, not like a kickdown downshift with throttle though.

 

[Meccanoble]

Will do and update you all

 

[bnjalal]

same here but didn't look at it yet, do update us if you find a fix.
A few weeks from now I plan on cleaning the throttle body, new air filter and clean the fuel injectors if I was feeling generous, if there's any changes ill post an update here

 

[Meccanoble]

I confirmed mine only does it when in gear. In neutral it does NOT happen. Sounds like torque converter related? Is there a solution other then replacing?

 

[novemberr]

I had a similar symptom. Not sure if it's the same as yours.
Mine also felt like jumping between gears when doing a hard brake. If I drove in gear M1-6 mode, which disabled v8-v4 shift, it disappeared.
So I did a BB tune to turn off AFM and the sudden smack disappeared.

 

[bigblackdog]

When I brake hard, I feel a slight delay reaction where it feels like I got hit in the back or like the rest of my car just caught up or something. I'll check the motor mounts again but it feels like its coming from rear. Any suggestions on what to look for?

Is there an associated noise? How long is the delay? All brake delays feel like they can be measured with a calendar but actually its micro-seconds usually,anyway, explain your version of "delay". Are there any signs of a bent or binding shock? Safe to assume you put your fancy pads on new rotors? Aside from upgraded rear sway bar links, did you inspect and/or alter the rest of the suspension. Some aftermarket and OEM components don't play well together.
You might ask a local tire shop or dealer to ride with you and show them the delay and associated action, bump, thump, whatever it is. Usually a ride, if you can duplicate it more than once and quickly, will be a free ride and perhaps some suggestions. I wouldn't tell them you do a lot of your own work.
As a 30 year mechanic, I would like you to explain the problem before the drive, point it out when it happens and then be quiet. Don't recite your self taught repair resume or offer suggestions or ask what 10 other noises are and what the light on the dash means, nobody likes to be taken advantage of when offering assistance.Let the man or woman assigned to go for the ride, do their job.
This was also free

 

[Meccanoble]

In my situation, no noise. A hard brake is made where truck does a slight nose dive. You tense up. Truck goes to a complete stop. You relax and you FEEL a thud right after, as if half the car was a dimension away and caught up. It almost feels like you got hit in the back. RPM's jump a slight bleep as shown in the video above. The delay is not even a second. Its just that the expectations are not there for it. Car has pretty much stopped its nose dive and settled to normal position, then THUD. I have not replaced any other suspension besides all sway bar end links and bushings.

I agree with you on limiting your feedback when getting a mechanic to examine. It opens their mind on what it can be when you dont give hints and they'll most likely blame me instead of a worn part if I sound like I fix everything. Unless I'm paying for the examination, I definitely want to only focus on the issue. I have found online feedback to be very useful and thus why I'm trying to understand what the issue can be before I pay or waste someone time. Appreciate the feedback.