# 2013 Ford Mustang bucks between 20-40 mph

**URL:** <https://community.cartalk.com/t/2013-ford-mustang-bucks-between-20-40-mph/169281>\
**Category:** Maintenance/Repairs\
**Tags:** mustang, ford\
**Created:** [August 28, 2020, 3:51pm UTC](https://community.cartalk.com/t/2013-ford-mustang-bucks-between-20-40-mph/169281 "2020-08-28T15:51:53Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![millerda](https://avatars.discourse-cdn.com/v4/letter/m/c67d28/32.png) [@millerda](https://community.cartalk.com/u/millerda)\
**Post date:** [August 28, 2020, 3:51pm UTC](https://community.cartalk.com/t/2013-ford-mustang-bucks-between-20-40-mph/169281/1 "2020-08-28T15:51:53Z")

</div>

Hi!  
My auto matic seems to shift hard, sort of buck, between 20 and 40 mph. Not all the time, but enough. I never had a six speed, so I at first thought it was something I needed to get use to. Is this normal, or a hint of something worse. It’s a six cylinder.  
Thanks very much!

---

<div class="post-metadata">

**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\
**Post date:** [August 28, 2020, 4:10pm UTC](https://community.cartalk.com/t/2013-ford-mustang-bucks-between-20-40-mph/169281/2 "2020-08-28T16:10:28Z")

</div>

Two things:  
Change the fluid, though Ford doesn’t say to, fluid should be changed every 30,000 miles.  
Check with a Ford dealership—there might be a computer update for your Mustang.

I can’t say about your particular car, my F150 has a 6 speed and my Mustang has the 4 speed automatic, both shift very smoothly.

---

<div class="post-metadata">

**Author:** ![davepsinbox\_157004](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@davepsinbox\_157004](https://community.cartalk.com/u/davepsinbox_157004)\
**Post date:** [August 28, 2020, 10:33pm UTC](https://community.cartalk.com/t/2013-ford-mustang-bucks-between-20-40-mph/169281/3 "2020-08-28T22:33:25Z")

</div>

I can’t add much except hard shifting is never normal and certainly not something you should “get used to.” Have your transmission checked out sooner rather than later. Some preventive maintenance could save your transmission and your wallet.

---

<div class="post-metadata">

**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\
**Post date:** [August 29, 2020, 11:35pm UTC](https://community.cartalk.com/t/2013-ford-mustang-bucks-between-20-40-mph/169281/4 "2020-08-29T23:35:01Z")

</div>

Is the check engine light on?

---

<div class="post-metadata">

**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/48514_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\
**Post date:** [August 30, 2020, 11:55am UTC](https://community.cartalk.com/t/2013-ford-mustang-bucks-between-20-40-mph/169281/5 "2020-08-30T11:55:31Z")

</div>

> [@millerda](#):
>
> My auto matic seems to shift hard, sort of buck, between 20 and 40 mph

Hard shifting does sound like a transmission issue.  
“Bucking” sounds like a driveability/engine issue.

I have to wonder…

\ ***Has the trans fluid ever been changed?** (It should have been done twice, so far.)  
\ ***Is the Check Engine Light lit up, or–even more serious–does the CEL flash/blink when you experience the “bucking” sensation?**