11-03-2014, 08:29 PM
Last edit by: IB Cristina
See related guides and technical advice from our community experts:
Browse all: Steering and Suspension Guides
- Why is My Truck Bouncing?
Guide to diagnose trouble and recommended solutions
Browse all: Steering and Suspension Guides
Rear end bounces @ 40-45 MPH
#16
11-23-2010, 10:13 AM
Tell them you want a vibration analysis done to the truck.
They can place sensors on the vehicle that will pinpoint the issue. I had this done on my 05 F-250 that has had a mid-truck, 48 mph, hop since it was new. The service manager at a local dealer duplicated the issue, agreed with the severity of the problem and did extensive vibration testing. He sent the results to Ford's engineers as he had 2 new trucks come back with the same issue.
End result was no fix.
Just be ready when Ford tells you that the condition is "Normal" and is just a characteristic of a HD truck.
They can place sensors on the vehicle that will pinpoint the issue. I had this done on my 05 F-250 that has had a mid-truck, 48 mph, hop since it was new. The service manager at a local dealer duplicated the issue, agreed with the severity of the problem and did extensive vibration testing. He sent the results to Ford's engineers as he had 2 new trucks come back with the same issue.
End result was no fix.
Just be ready when Ford tells you that the condition is "Normal" and is just a characteristic of a HD truck.
#17
11-23-2010, 12:18 PM
Posting Guru
Join Date: Apr 2004
Location: Corinth, TX
Posts: 1,399
Likes: 0
Received 0 Likes
on
0 Posts
#18
11-23-2010, 05:38 PM
My srw long bed cc fx4 6.7 psd does not have it...just to add to the list.
Btw my vote is for the driveshaft assy or pinion angle! I would add torque converter shutter but you said it doesnt matter what gear it is in.....If you get a chance drive the truck at said speed with your foot lightly on the brake pedal while still accelerating (this will unlock the converter) to rule out the converter....next check the ujoints and pinion angle then move on to the driveshaft assy.
Btw my vote is for the driveshaft assy or pinion angle! I would add torque converter shutter but you said it doesnt matter what gear it is in.....If you get a chance drive the truck at said speed with your foot lightly on the brake pedal while still accelerating (this will unlock the converter) to rule out the converter....next check the ujoints and pinion angle then move on to the driveshaft assy.
#19
11-23-2010, 06:54 PM
Join Date: Apr 2010
Location: Panama City, FL area
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for all the great inputs! I value all of these including the ones who say thier truck doesn't do it.... that helps my cause alot! Interesting, I may start a poll and see just how many SDs do have the SD bounce....
Todays updates:
1) Took 4 tires/wheels of new truck (second time) didn't fix it. contacted engineers again.
2) Replaced both drive shaft sections and carrier bear. didn't fix it again. contacted engineers again.
3) Installed vibration monitoring equipment and captured the vibes. 7.4 hz, 14.8 hz, and 81.4 all recorded with ~.05g's. These are definately some sort of harmonics...just need to figure out what is causing them. Sent data to engineers and awaiting response.
Everything they have changed only leaves two areas in the rear of the truck... shocks/springs and rear end/axles. (and sncbluegt's input which I saw after posting my update, thanks)
Todays updates:
1) Took 4 tires/wheels of new truck (second time) didn't fix it. contacted engineers again.
2) Replaced both drive shaft sections and carrier bear. didn't fix it again. contacted engineers again.
3) Installed vibration monitoring equipment and captured the vibes. 7.4 hz, 14.8 hz, and 81.4 all recorded with ~.05g's. These are definately some sort of harmonics...just need to figure out what is causing them. Sent data to engineers and awaiting response.
Everything they have changed only leaves two areas in the rear of the truck... shocks/springs and rear end/axles. (and sncbluegt's input which I saw after posting my update, thanks)
Last edited by Thom12; 11-23-2010 at 06:55 PM. Reason: added last line
#20
11-23-2010, 07:14 PM
Posting Guru
Join Date: Aug 2004
Location: Upstate, NY
Posts: 2,402
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for all the great inputs! I value all of these including the ones who say thier truck doesn't do it.... that helps my cause alot! Interesting, I may start a poll and see just how many SDs do have the SD bounce....
Todays updates:
1) Took 4 tires/wheels of new truck (second time) didn't fix it. contacted engineers again.
2) Replaced both drive shaft sections and carrier bear. didn't fix it again. contacted engineers again.
3) Installed vibration monitoring equipment and captured the vibes. 7.4 hz, 14.8 hz, and 81.4 all recorded with ~.05g's. These are definately some sort of harmonics...just need to figure out what is causing them. Sent data to engineers and awaiting response.
Everything they have changed only leaves two areas in the rear of the truck... shocks/springs and rear end/axles. (and sncbluegt's input which I saw after posting my update, thanks)
Todays updates:
1) Took 4 tires/wheels of new truck (second time) didn't fix it. contacted engineers again.
2) Replaced both drive shaft sections and carrier bear. didn't fix it again. contacted engineers again.
3) Installed vibration monitoring equipment and captured the vibes. 7.4 hz, 14.8 hz, and 81.4 all recorded with ~.05g's. These are definately some sort of harmonics...just need to figure out what is causing them. Sent data to engineers and awaiting response.
Everything they have changed only leaves two areas in the rear of the truck... shocks/springs and rear end/axles. (and sncbluegt's input which I saw after posting my update, thanks)
#21
11-23-2010, 07:30 PM
Join Date: Apr 2010
Location: Panama City, FL area
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
Ever since I picked up my truck (350 6.7, c/c, srw, lb) I get a "bounce" in the back of the truck right at 40 mph and it stops right at 45 mph. My first thought was that I have a bad tire. I have 18" Continental A/S tires on it. The bounce gets progressively worse if I stay between 40-45 mph but clears right up if I slow down or speed up out of that speed range.
This week I took the truck in because of the change oil light came on with only ~1200 miles since oil change. I finally remembered to tell the service department about the bounce. They had my truck for 3 full days and all they have managed to do is confirm my complaint, not fix it. They road pressure balanced the tires 3 times and they still had the bounce. They called the Ford hotline and were told to take the tires off of a brand new lot truck and see how they were. The bounce is still there with the brand new tires.
The bounce is unaffected by rate of excelleration or gear the tranny is in... it just happens at 40-45 mph no matter if I drive like my granny or a jack rabbit. I have heard comments like "its the nature of the beast" but I don't think so.
I took my truck back for the weekend but the tech is waiting on another reply from the hotline as to what to do next.
Since the new tires didn't help my next guess is the drive shaft or rear end since it is definately speed related.
I just realized that I don't think I notice it when I am hauling my 5'er but I am not 100% sure about that.
Anyone have any thoughts?
Thanks,
Thom
2011 F350 6.7L PSD C/C SRW long bed w/ 5'er package.
This week I took the truck in because of the change oil light came on with only ~1200 miles since oil change. I finally remembered to tell the service department about the bounce. They had my truck for 3 full days and all they have managed to do is confirm my complaint, not fix it. They road pressure balanced the tires 3 times and they still had the bounce. They called the Ford hotline and were told to take the tires off of a brand new lot truck and see how they were. The bounce is still there with the brand new tires.
The bounce is unaffected by rate of excelleration or gear the tranny is in... it just happens at 40-45 mph no matter if I drive like my granny or a jack rabbit. I have heard comments like "its the nature of the beast" but I don't think so.
I took my truck back for the weekend but the tech is waiting on another reply from the hotline as to what to do next.
Since the new tires didn't help my next guess is the drive shaft or rear end since it is definately speed related.
I just realized that I don't think I notice it when I am hauling my 5'er but I am not 100% sure about that.
Anyone have any thoughts?
Thanks,
Thom
2011 F350 6.7L PSD C/C SRW long bed w/ 5'er package.
Yes as stated in my OP (not trying to be sarcastic, the board would not let me respond with a simple "yes", had to be 10 charictors before it will allow the post...think I got 10 now
)
#22
11-23-2010, 07:42 PM
Posting Guru
Join Date: Aug 2004
Location: Upstate, NY
Posts: 2,402
Likes: 0
Received 0 Likes
on
0 Posts
I was afraid of that. The previous body style had this same issue. It was a harmonic in the frame that usually could not be fixed. I wish you luck on this one. Many were told they had to live with it.
#23
11-23-2010, 08:32 PM
Just to throw this out there....I have had similar problems in the past with mustangs. If ford does not fix it and you figure you will have to take it into your own hands and possibly hand over the bill to ford when you get it figured out...take the truck to a "high performance" suspension shop where they use lasers to get the suspension right on hot rods...gather as much info as you can as to where the specs are suppose to be and try that...in my years at dealerships I have only found one tech that had tools like that and its because he has 250k race car that ran 7s.
#24
11-23-2010, 09:21 PM
#25
11-23-2010, 11:27 PM
#26
11-24-2010, 07:19 AM
Join Date: Apr 2010
Location: Panama City, FL area
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
#27
11-24-2010, 08:30 AM
Elder User
Back in the mid 90's I had a F250 with the same issue. After about 20 trips to the dealer, who was able to reproduce the problem, and a few set of new tires on Ford, it was traced to the drive shaft. They sent it out to a drive shaft place and never had the problem again. FWIW i had a big heavy Reading box on the rear so lack of weight in the bed was not an issue.
#28
11-24-2010, 09:10 AM
Elder User
Join Date: Dec 2005
Location: Lebanon TN
Posts: 577
Likes: 0
Received 0 Likes
on
0 Posts
I have a short bed crew cab. Mine will shake your internal organs at prolonged constant speed of 50mph. (my wheels have been balanced twice) It will go to another dealer (where I bought it) next week, just haven't had a chance to get it to the folks I bought it from (I live over two hours away from them). I spoke to them yesterday, they assured me they will get to the bottom of it. Anyway, there is a serious problem with the truck.
This is one of those problems where a dealer can just throw up their arms and say "that's a characteristic of the truck" and send you packing. They told me I needed to just put alot of weight in the bed and I'd be fine. (Which the Ford dealer in Lebanon TN did) I know it will take several trips to the right dealer, patience, and back & forth with Ford. It's like fighting cancer, you've got to commit to the diagnosis & treatment, find the right doctor, and not accept the diagnosis as terminal with no treatment options.
Thom12, please keep us posted as I will do.
This is one of those problems where a dealer can just throw up their arms and say "that's a characteristic of the truck" and send you packing. They told me I needed to just put alot of weight in the bed and I'd be fine. (Which the Ford dealer in Lebanon TN did) I know it will take several trips to the right dealer, patience, and back & forth with Ford. It's like fighting cancer, you've got to commit to the diagnosis & treatment, find the right doctor, and not accept the diagnosis as terminal with no treatment options.
Thom12, please keep us posted as I will do.
#29
11-24-2010, 10:07 AM
Posting Guru
Join Date: Apr 2004
Location: Corinth, TX
Posts: 1,399
Likes: 0
Received 0 Likes
on
0 Posts
#30
11-24-2010, 10:54 AM
Join Date: Apr 2010
Location: Panama City, FL area
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
I was with you all about the drive shafts being the culprit until yesterday when they changed both shafts and the carrier bearing as directed by the engineers. It did not change a thing. same vibs at the same speeds.
Called the dealer this morning and told them I want my truck for the long weekend and he informed me that Ford is sending down an engineering team next week to investigate.
At least they are not blowing it off (for now anyway) as the nature of the beast.
Thom
Called the dealer this morning and told them I want my truck for the long weekend and he informed me that Ford is sending down an engineering team next week to investigate.
At least they are not blowing it off (for now anyway) as the nature of the beast.
Thom