Tranny clunking

Reply Subscribe

Thread Tools

Search this Thread

Sep 7, 2021 | 11:17 AM

PNGento

Thread Starter

Cross-Country

Joined: Apr 2017

Posts: 89

Likes: 7

Tranny clunking

I have a 2017 Super Duty dually with 102K miles. For about the last 5K miles, when the truck is cold (not outside temperature, but when it has sat overnight), I'm noticing two issues. The first is often when starting off, I will feel a slight slipping in the tranny. Second issue is when I first get up to around 40 or more MPH of speed and then come to a slow to heavier braking and then when the truck's speed drops to around 15 to 10 MPH, I hear and feel a very distinct clunking (just a single clunk, but even passenger very much notices it. Almost feels like the truck is dropping several gears instantaneously.

Wondering if anyone has a thought as to what might be occurring or if anyone has had a similar issue and how it got resolved. I've brought it up to 2 dealers, but since it is my only ride, I haven't been able to leave with them, but now have an appointment, but not for another week, so hoping someone can offer some thoughts as to what might be going on so I can share with the shop.

TIA

Sep 7, 2021 | 11:28 AM

scraprat

Lead Driver

Joined: Jan 2002

Posts: 8,679

Likes: 4,783

From: Itinerant

Can't really help you on the "clunk" but has the transmission had a it's fluid changed?

Sep 7, 2021 | 01:24 PM

PNGento

Thread Starter

Cross-Country

Joined: Apr 2017

Posts: 89

Likes: 7

Taking it in on Thursday for that to be done.

Sep 7, 2021 | 05:58 PM

Lamoon78

Fleet Mechanic

Joined: Nov 2019

Posts: 1,250

Likes: 192

From: Livingston Tx

Never listen to Fords service intervals they are ridiculous. Especially if you use the truck for what it’s intended for.

Sep 7, 2021 | 08:34 PM

morehouse7

Fleet Mechanic

Joined: Mar 2021

Posts: 1,455

Likes: 607

When you fist hop in after an overnight, do you start it and put it in drive right away? Or does the truck idle for a minute and then you put it in gear? If #1, try #2 and see if you feel "slipping" still. Clunk, not sure. I have a driveline clunk like lots have reported, I think it's normal.

Sep 7, 2021 | 09:56 PM

grumblin

Senior User

Joined: Jul 2020

Posts: 176

Likes: 18

I had a "clunk" on my 2020. At service, i asked the SA to check the clunk. Got an urgent call - transmission was missing 3 nuts on the transmission mounts. Not good.