I know I've read a thread on here before, but it's been awhile.

What would cause driveline bounce between 40-50mph? Is there anything that stop this? It's getting pretty bad.

 

My NLTD tunes usually shift into overdrive around 45-48mph and shortly after that shift the bouncing clears up and I don't feel it again until I need to slow back down and while decelerating it does it again from 50 to 40 and then it's gone.

 

Driveline frequently does that, but it will do it while coasting in neutral at "bounce speed".

One other possibility is fueling at that load/RPM range.

 

Any ways to cure this?
Traction bars?

 

I had to take my driveline in to a driveline shop. They replaced the U-joints and carrier bearing, trued the driveshaft (it was bent) and balanced it.

 

I can do the ujoints myself....

Did they just replace the carrier bearing or is there a bearing you would recommend?

I have a local shop.... But it's my daily driver....

 

My driveline shop has Neapco - which is what the OEM was. It worked for a long time the first time, so I saw no reason to change.

 

Alright. Thanks Tugly.
I'm guessing the bounce can only get worse.

 

Tugly,
What do you think of spicer ujoints and carrier bearing?

 

DH...
Many of us experience the bounce at those speeds.

I had some pretty exaggerated hop so i lifted all 6 paws off the ground and set em spinning in drive...

I found a tire worn out of round at rear passenger inner. Getting fresh rubber helped but the bounce persisted.
I swapped out carrier bearing at the last south texas tech weekend and that made considerable improvement... but the bounce persists.

Next on the list is ujoints...

 

I've replaced my entire driveline trying to stop the 40mph bounce.
I finally realized that a seizing rear caliper was the source.
I replaced both rear calipers but a warped rotor is causing the issue all over again at 40 mph. This time only while on the brakes.

 

I just did a brake job all the way around. All my calipers were properly compressing.

I contacted my local driveline shop and he said for 300 bucks, he will balance the driveshaft, replace all the ujoints and carrier bearing.

When I bought the truck the front tires were slightly capped.... I never rotated em.... Oops. They only got worse. Finally put them on the rear and flattened them out over time. I just had my tierods replaced so I do have a brand new allignment done.

My tires are getting bare but like I said they are even. I do need new ones probably after the snow fall.

I think I'm gonna do the driveline work next month, try that and then see what happens. If worst comes to worst I'll buy new tires for the winter.

Thanks for info fellas. I have precision ujoints sitting on the shelf at home. Just no time to drop the shafts.

 

My '02 F350 SRW has had the 40 mph bounce since I bought it 3 years ago. I got under it back then and shook it around really good at both ends and at the carrier bearing and it was pretty solid so I just wrote it off to the shaft being a little out of balance. It started getting progressively worse over the past few weeks to the point that I thought one of the gears in my tranny was goofed up or something.

So I took it to a recommended guy (I try to do my own work when practical but I need my truck to tow a trailer towards the end of this week) to look at it.

He took it for a test drive and immediately said it feels like the carrier bearing. When we got back he got under it with a creeper and when he shook around the rear end of the driveshaft it rattled around like there was not a single needle left in the u-joint bearings. I was really embarrassed.

He said it was so wallowed out that the driveline shop would likely have to weld a new yoke on it. So he is getting that fixed and having it balanced and replacing the joints and carrier bearing so I can't wait to see what it is like to drive it.

I guess the moral of this story is, if your driveline feels out of balance, then it probably is. And if you don't correct it, the vibration will destroy all the stuff holding it in place.

I felt like an idiot when he rolled under there and rattled that driveshaft around like that. I had already done that - three years ago. Right...

 

I wish I could help, but I know nothing about them.

Franko72 - Didn't you feel it when you used the brakes? My thinking is that you would feel it more while braking than coasting.

I use a temperature sensor to check things out, but it didn't really point to anything obvious - it just told me it wasn't brakes.

Shake the carrier bearing - it should be pretty firm, but with a little "rubber" give. If it's sloppy, it's done.

 

When looking at bearings and such, I look at the country of manufacture above anything else. I would never use anything made in china. I have never seen a quality chinese wheel bearing. While I haven't had much experience in u-joints, I bet quality is the same as wheel bearings. Look at the place of manufacture.