High Pitch Noise While In Gear And Off Throttle

[StaffyStella]

Hey Guys,

So after three years I finally got my Bronco back on the road today. Drove about 50 miles with no issues at all. Only thing that is bugging me is a high pitched fast rhythm "ting, ting, ting" when I am in gear and coasting, generally right after I left off the throttle and the transmission catches and starts to naturally slow my speed. I am running an original 302 with a NP435 with a 9" rear. Any ideas? Any input is appreciated.

Thanks,

Ben

 

[okie4570]

Rear drive shaft u-joints? Have heard an incorrectly rear pinion gear sing when not adjusted properly too, but not really a ting sound. Header noise possibly?

 

[StaffyStella]

Rear drive shaft u-joints? Have heard an incorrectly rear pinion gear sing when not adjusted properly too, but not really a ting sound. Header noise possibly?

Thanks for your input Okie. It could quite possibly have something to do with the drive shaft u-joints, we planned to grease them today, only to realize we were out of grease. But wouldn't they make the noise all the time since they are constantly spinning?? I am not too knowledgeable when it comes to mechanics so that is purely a question and not me questioning your possible culprit.

It is kind of a singing/ting mix I guess. Its next to impossible to describe sounds. Its like a singing sound with distinct tings (as the transmission "bounces"/"lopes" after it catches when I let off the gas).

I realize this is a shot in the dark, just hoping someone has had this exact issue and can pinpoint the problem.

Thanks,

Ben

 

[bdavis70]

My Bronco sat for 7 or 8 years and after I got it going again I have a noise that reminds me of gears meshing together. I only get it when I let of the gas and coast. I dropped the rear drive line a took it for a ride and didn't hear the noise. I pulled the third gear and had it check because I thought I had a bearing going out. Everything looked good and I had it set back up but I still had the noise. When I had the third gear out I notice my ring gear was pitted where it was out of the oil all those years. My rig is sitting again so I haven't replaced my ring gear yet so I'm not sure that is what it is, but might be a place to look. Good luck. Brian

 

[El Kabong]

Coast applies different pressure than acceleration, so u-joints might make noise one way & not the other. A failing U-joint can definitely cause a ting ting ting sound, but it is usually worse under acceleration. They still should be checked. A loose pinion nut on the rear end can cause a lot of noise, & it is normally worse during deceleration. It is usually more of a heavy whine than a ting, but since it shows up on while decelerating, it is something to check. Singing could describe that loose pinion sound too.

I would park it on flat ground, block the wheels, set the E-brake, & put it in neutral to release any load from the driveline. Then crawl under there & check for any u-joint movement. Try to move pieces differently on either side of the joints. And check the pinion nut. Also check for loose exhaust components, or anything that might move & contact the driveshaft. Look at U-bolts holding the axle to the springs. Are they loose, allowing the nose of the rear end to drop too far under decel, putting an odd twist on the joints?

Sometimes a ting ting ting can be related to something that moves under the hood, interfering with the fan, alternator fan, or other spinning components. Bad motor mounts can sometimes allow an engine to shift during accel or decel, allowing something nearby to be hit.

As bdavis70 mentioned, pulling the rear driveshaft & driving in 4wd will allow you to see if it is in the engine or trans, or if it is further back.

Can you tell sort of where it comes from? Sometimes driving with another vehicle alongside, listening forward & back, can narrow it down. You might try that if you don't find it in the other checks. You don't want to drive it anymore than you have to until you figure it out, since a U-joint can fail completely & cause more damage.

 

[broncnaz]

Couple of things I would check is the harmonic balacner outer ring. Sometimes the rubber comes out and the outer ring will spin and can cause a ting sound. Also the engine spacer plate may have something hitting it. Lots of possible culprits could be something hitting the exhuast or even a rock or something in the muffler.

 

[tatersalad]

the large nut at the driveline attaching point of the nine inch third member (I believe it called the pinion nut) if it has backed out you will hear a whine when coasting.

 

[jkskier]

I would suggest jacking up your rear end and spinning the wheels by hand, too. That helped me locate a frequent whirring/chirping sound coming from the metal dust shield having worked itself rearward and contacting the iron on the third member.

 

[StaffyStella]

My Bronco sat for 7 or 8 years and after I got it going again I have a noise that reminds me of gears meshing together. I only get it when I let of the gas and coast. I dropped the rear drive line a took it for a ride and didn't hear the noise. I pulled the third gear and had it check because I thought I had a bearing going out. Everything looked good and I had it set back up but I still had the noise. When I had the third gear out I notice my ring gear was pitted where it was out of the oil all those years. My rig is sitting again so I haven't replaced my ring gear yet so I'm not sure that is what it is, but might be a place to look. Good luck. Brian

Thanks Brian, I'll give this a shot to see if I still have the sound. Get that thing back together!

 

[StaffyStella]

Thanks everyone for the input! I'll start working my way through these suggestions and let you guys know when/if I get it figured out.

I really appreciate you guys taking the time to provide your input.

-Ben

 

[StaffyStella]

Well, found what I believe to be the problem. A completely failed u joint in the CV to trans case yoke. Looks to be pretty bad with quite a bit of gouging into both the CV joint and the trans case yoke. Took it to Universal Service here in Charlotte and Tim (great guy, extremely helpful) suggests I replace both incorrectly worn pieces. The trans case yoke is worn so badly on one side that the bolt hole has less than half the inner wall (u joint side) left and the CV joint is gouged from contact with the trans case yoke. I have pics I'd like to share but haven't taken the time to become a member yet. Anyway, Tim is rebuilding the shaft with Spicer joints for $75, which I thought was pretty good, and ordering me a new Spicer CV joint as well.

My question is about the trans case yoke. I have been trying to find one (Spicer also) and haven't been able to find one. Do I really need the Spicer brand for my mostly street ride? Tim has been warning me of the China junk, so just wondering if there really is a noticeable difference.

Again, I appreciate you guys help....most were dead on with the diagnosis ��