Driveline Vibes Or ?

indyF-350psd · May 3, 2013

ok fellas here lately my truck has developed a shimmy or vibration when braking from about 20 mph down to about 10 mph....all the brakes are good slide pins are not stuck.....it seems like it happens when my rpms are lower....would a weak power steering pump cause this? maybe its not pumping enough fluid for the hydroboost? or do you think it might be drive shaft vibes? need some suggestions on what to check or any ideas please.....

Lethalthreat7.3 · May 3, 2013

Check your hydro-boost. Mine did the same thing. I found it just starting to leak at the firewall. It felt like warped rotors.

JLDickmon · May 3, 2013

torque convertor trying to unlock

Lang · May 3, 2013

Check your rotors

indyF-350psd · May 3, 2013

JLDickmon said:
torque convertor trying to unlock

have a BTS...only about 3 years old and 12000 miles on it....i did kinda think this for a bit so i took out my gearhead chip and stuck in my swamps chip to see if there was a difference in the shifting but its all the same regardless of tunes....

Lethalthreat7.3 said:
Check your hydro-boost. Mine did the same thing. I found it just starting to leak at the firewall. It felt like warped rotors.

didnt really find any leaks but not ruling this out yet....

Lang said:
Check your rotors

rotors have just been turned...the fronts were fine and the rear had a teeny bit of warpage due to stuck calipers.....replaced those and fronts were replaced last fall....barely have a coating of rust on them....

i also thought of another detail.....if i go about 50 mph and slam on the brakes the vibration is more potent....everything points to rotors and such but i have been through all 4 sides to double check....

Lang · May 3, 2013

Jack your tires up and check your ball joints and hub bearings

JLDickmon · May 3, 2013

indyF-350psd said:
have a BTS...only about 3 years old and 12000 miles on it....i did kinda think this for a bit so i took out my gearhead chip and stuck in my swamps chip to see if there was a difference in the shifting but its all the same regardless of tunes......

put it back in "stock" then take the chip out altogether.. and see if it does it with OD cancelled.

You're Johnny-On-The-Spot on this one.. you're gonna have to decide whether it's closest to wheel RPM or driveline RPM and go from there...

JLDickmon · May 3, 2013

hey.. how old is the steering damper?

indyF-350psd · May 4, 2013

Lang said:
Jack your tires up and check your ball joints and hub bearings

hub bearings and ball joints are both about a year old with less than 5k on them done by a good shop.....

JLDickmon said:
put it back in "stock" then take the chip out altogether.. and see if it does it with OD cancelled.

You're Johnny-On-The-Spot on this one.. you're gonna have to decide whether it's closest to wheel RPM or driveline RPM and go from there...

went to town to get some stuff and tried this....no real difference with od cancelled.....however i did get going about 55 and shifted into to neutral and hit the brakes hard.....smooth as silk....thinking its trans related....my driveshaft i had rebuilt about 3 years ago by a driveline shop so new u joints and balancing there.....

JLDickmon said:
hey.. how old is the steering damper?

maybe 3 years?!?!?!?

neverkickn · May 4, 2013

JLDickmon said:
put it back in "stock" then take the chip out altogether.. and see if it does it with OD cancelled.

You're Johnny-On-The-Spot on this one.. you're gonna have to decide whether it's closest to wheel RPM or driveline RPM and go from there...

If it is only doing it from 20 down then how would that help. The tc shouldn't be locked there, od switched out or otherwise, less he has a switch.

If it only happens when braking, I would keep my focus on brakes for now. Have you had it up in the air to just have a good look at everything?

indyF-350psd · May 4, 2013

neverkickn said:
If it is only doing it from 20 down then how would that help. The tc shouldn't be locked there, od switched out or otherwise, less he has a switch.

If it only happens when braking, I would keep my focus on brakes for now. Have you had it up in the air to just have a good look at everything?

spent my last 2 days off checking everything out after i cleaned up the sticking rear calipers.....could the booster be going bad even if it isnt leaking?

JLDickmon · May 5, 2013

neverkickn said:
If it is only doing it from 20 down then how would that help. The tc shouldn't be locked there, od switched out or otherwise, less he has a switch.

If it only happens when braking, I would keep my focus on brakes for now. Have you had it up in the air to just have a good look at everything?

well, really.. if the truck was over 45 mph to begin with, the TCC should have locked in.. so it it should be unlocking as the truck rolls through oh, somewhere in the 1,200 rpm area..

I hate internet technicianing on ride disturbances because if you say, "Well, check X, Y, and Z." And forget W, the problem for sure is going to be Q

Dmstrucks02 · May 5, 2013

Have you checked the carrier bearing?

indyF-350psd · May 5, 2013

Dmstrucks02 said:
Have you checked the carrier bearing?

no havent checked that yet.....will do tomorrow...

Lethalthreat7.3 · May 6, 2013

Tried to tell you that it is the hydro-boost. My truck did the exact same thing. I went through EVERYTHING. there is a possibility that it is something else but if I were to write a discussion on what my truck was doing it would be faster just to quote your write-up. I found an outfit in Georgia(I think) for $125. New they are something like $470 fromFord

JLDickmon · May 6, 2013

Lethalthreat7.3 said:
Tried to tell you that it is the hydro-boost. My truck did the exact same thing. I went through EVERYTHING. there is a possibility that it is something else but if I were to write a discussion on what my truck was doing it would be faster just to quote your write-up. I found an outfit in Georgia(I think) for $125. New they are something like $470 fromFord

did your truck have any other symptoms?
brake pedal returning slowly, etc., besides the leak?

JLDickmon · May 6, 2013

the other thing to try..
let it coast down with the OD cancelled.. so it uses engine braking to stop..

if it still shakes, you eliminated the brakes..

but one thing that makes me think you've got yourself chasing your tail..

i also thought of another detail.....if i go about 50 mph and slam on the brakes the vibration is more potent....everything points to rotors and such but i have been through all 4 sides to double check....

you might have re-created your own problem right there..

Lethalthreat7.3 · May 7, 2013

No, everything else was normal. Transmission gear range is irrelevant. The only time I could get it to go away was occasionally under a load. I replaced all four rotors, pins and installed ceramic pads. Changing the hydro-boost is what finally fixed the issue. Believe me I am tight with $ and will not throw parts at problems. This was was a pain in the arse to diagnose but sounds identical to the same issue you are having.

JLDickmon · May 7, 2013

I payed attention to mine last night going home..
with the OD cancelled, mine unlocks as it's slowing through 25 mph

with the OD enabled, it was more like 40 mph..

so I guess I would have to ask again, "..is it more wheel rpm, or driveline rpm in frequency?"

Copracr · May 7, 2013

indyF-350psd said:
.however i did get going about 55 and shifted into to neutral and hit the brakes hard.....smooth as silk....thinking its trans related....

So right here you eliminated the braking system as the culprit. You want to double check the hydroboost system though. Get up to 55, switch to neutral, then get the engine rpms to 1500 and hold it there. Then hit the brakes with your other foot (gently, remember it's your left foot and you're not used to using it for that). If it's still smooth as silk then your trouble is in the tranny or the programming.
That's my armchair quarterback suggestion.