Driveline "Ticking" Noise on Deceleration

rheltzel

rheltzel

Senior Member
My '35 (stock drivetrain) has developed a "ticking" noise when I let the throttle off. It's not the engine (not RPM sensitive and makes it even if the engine is shut off). Not a bearing noise. Makes the same noise in all three forward gears (although most prominent in 2nd and 3rd). Obviously thrust related. Nothing visually obvious. Started all of a sudden while going down the freeway. Doesn't happen when car is first started in morning; starts after about a mile and then constant whenever coasting.

I'm thinking the universal joint. I suppose it could be the output shaft of the transmission, although it was recently rebuilt.

Any ideas?
 
mfagan,

Good thought. Checked; all lug nuts torqued to 120 ft/pds.

JM 35 Sedan,

I thought about that, but did yours do it only under deceleration, or all the time? I can't figure out why it would do it only on deceleration and not when throttle is on.
 
That pin must the hardened proper part to anchor the driveshaft to the pinion, and be peened. Another place that can cause that noise is a loose or missing bolt, or correct spacer, that "fat washer", that goes under the bolt that holds the u-joint to the transmission shaft. An ordinary washer will allow the joint to move. The part number for the spacer is B-7095. The part number for the pin is 48-4607. If you have a six spline pinion, that pin length will have to be trimmed to allow the correct peening.
 
JM 35 Sedan,

I thought about that, but did yours do it only under deceleration, or all the time? I can't figure out why it would do it only on deceleration and not when throttle is on.[/QUOTE]

Yes, ticking and scraping noise occurred during deceleration, as soon as I let up on the gas. I think the ticking sound happened as the peened end of the pin that was sticking out rubbed across the welded joint on the torque tube. Go back to my previous post and click on the link I added that goes back to the post I made eariler this year in May.

If the pin is your problem, you may want to think about finding and using one of these Champion Safety Pins. The spring/half collar holds the ends of the pin from coming out.
 

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John,

I'll bet that's it. A friend of mine also suggested the driveshaft pin and I had a hard time understanding why it would do it under deceleration, and not acceleration, but you have confirmed that's possible. In any event, I'll have to drop the rear end and in the process can check the u-joint while I'm at it.

Thanks to you and the others who responded. I am grateful.

Richard
 
You do you lug nuts up to 120!!
I'd love a couple of those safety clips.. Where would you find those now...??
Not far off doing the reassembly and starting to get worried on how to peen those pins over and making them stick..
 
Lug nuts should only be torqued to 70-80 Ft. lbs. You could break a stud or damage the wheel by over-tightening.

The ticking only occurs on decelleration because the load and forces are lighter on the drive shaft allowing the pin to shift more.
 
I also thought 120 sounded a bit high.

Talkwrench: I was thinking about the pins, and thought the next one I do, I will have it so the ends do not stick out too far after peening, and then put a hose clip around the coupler, surrounding the pin. Two hose clips, 180 degrees apart, one over each pin.

Just an idea. Anyone think why that wouldn't work? I'm not sure there is enough clearance, as I said, it's just an idea.

Mart.
 
To properly peen the pin, be sure it is not too long. Hold a large hammer under the head of the pin, and pound the other end around the edges with a ball peen hammer until it is secure. Only the correct pin with a head on one end should be used.
 
In my experience a hardened pin will fail quicker than a soft pin. Grade 8 bolt will not have as much "give" as a grade 5 for instance. The bolt grades used as reference here. But similar hardness pins will do the same.
The slight give in the softer pin will work in a spline that has a some wear.
Martin.
 
Gotta back up my buddy here, I used an allen headed quarter inch bolt and it snapped. The softer pin I replaced it with is still in there. The same parts were used. Allen bolts are a good grade of high tensile steel, but not appropriate in this instance.
 
Mart, Ive been thinking about your idea of hose clamps. .mmm Im not so sure on that one, unless you mean the type that are flat like you would use on a CV joint boot..?? Perhaps a small braze would hold it in position and stop it sliding off, or just do that on the edge of the pin?

Im still trying to find a good drive shaft.. May convince my wife I need a Mitchell ; o P
 
I finally dropped the rear end today. Turns out JM 35 Sedan and my friend P Menz were correct in their diagnosis...it was the pin that holds the driveshaft to the pinion shaft.

The prior owner of my car had the rear end ratio changed. The moron who did the work apparently drilled out the peened end of the pin, did the work, and then used the same pin to put it back together. It was held in place by...wait for it...duct tape. Yep. You read right. Duct tape.

I can only hope he didn't do the work on the actual differential.

My thanks and admiration to JM 35 Sedan and my friend P Menz for their spot-on diagnosis.


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I believe that wear in the splines of the coupler /and or the pinion is what causes this. The pin only keeps the driveline from moving forward or back. Once there is play in the splines, it will slightly bend the pin back and forth, work hardening it and it will eventually fail. That is why a harder pin will fail sooner.
I was wondering why you couldn't drill and tap the holes in the coupler, make 2 special pins like turned down flat head allens that were already in 2 pieces and locktighted in so they couldn't unscrew themselves? There really isn't any force on the pins except to keep the driveline from moving fore and aft.
 
:rolleyes: Duct tape can't do everything. It is important to make sure the spline and coupler is in good condition. On mine ( slightly later model) I did manage to get a good shaft and coupler. In fact I had a new coupler, the new one was not as good as the old one! I even measured it, of course I used the old one with new pin, I even had to tap the shaft in! The trick with the pins is to drive them over enough without flattening them too much as you thin out the edges and I'm sure that's what breaks off easy over time.. I think even with mine I went too far.
 
JM 35 Sedan said:
JM 35 Sedan,


Yes, ticking and scraping noise occurred during deceleration, as soon as I let up on the gas. I think the ticking sound happened as the peened end of the pin that was sticking out rubbed across the welded joint on the torque tube. Go back to my previous post and click on the link I added that goes back to the post I made eariler this year in May.

If the pin is your problem, you may want to think about finding and using one of these Champion Safety Pins. The spring/half collar holds the ends of the pin from coming out.[/QUOTE]

If you think about it the reason these pins brake is because of the sloppiness / looseness of the spline & the coupler.
I think with that type of condition even the Champion Safety Pin will Fail.
The only difference is the broken parts will stay in place.

I don't know this answer But if the pin is completely sheared can the coupler slide to the point that it will disconnect from the pinion.
And if that happens it could strip / aka destroy the end of the pinion as it cones off.

So it comes down to You can have all the rear end bolts the proper grade Properly torqued Safety wired where needed , Lug nuts torqued along with the hubs & if the spline & coupler if loose
we are trying to drive the Car / Truck with a 1/4" pin.:eek:

We have to figure out a way to tighten up the slop in the splines & Couplers in these 60 + year old vehicles .
Click to expand...
 
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