Mysterious Vibration from 1950 Dodge Wayfarer Roadster - seems like we've tried everything - help!

[grandpas50dodge]

Hi all, based on some comments, I thought I'd revise things for clarity.

 

I'm posting on behalf of my grandpa, who wouldn't touch a computer with a ten foot pole. He's been chasing down a bad vibration in his 1950 Dodge Wayfarer Roadster with a 3spd fluid drive. 

 

The vibration is felt throughout the vehicle when running - regardless of whether it's in gear or not - and is worse at higher rpms.

 

Years ago, when it started leaking oil from the rear main seal, he discovered that the rear main bearing had been pounded out. 

 

That prompted him to purchase a rebuilt fluid drive coupling, but after installing, the problem was worse.

 

He then thought it might be the camshaft - so he had the engine pulled and had the one from his parts car rebuilt and installed. The rebuilt engine was dyno'd and is perfectly smooth. 

 

It seems like we've isolated the source of the vibration to the fluid drive. 

 

- motor mounts have been replaced

- drive shaft hasn't been checked, but seems unlikely since the problem happens in or out of gear

- rebuilt fluid drive has no leaks and fluid has been checked

- transmission was rebuilt a while ago and should be tip top

 

My thought is that the original fluid drive may have had a problem, and with time that caused a vibration, and eventually damage to the rear main bearing.

However, from what I've read here, rebuilt fluid drives are kind of a nightmare, and it doesn't surprise me that one could make the vibration significantly worse, since the clutch would wander from lack of centering. That would also explain why it's worse at higher rpms. 

 

He's still got the original fluid drive, and may have a line on another untampered one. Is there a way we could test them before installing to see if they function properly? 

 

I'm heading down to see him next week, and I'll try to get a video of the problem, and any more useful information I can get.

 

Thanks everyone for the comments so far, as well as your patience. 

Edited September 7 by grandpas50dodge
Clarity

[Doug&Deb]

What was the reason for replacing the fluid coupling? I’m thinking you’re on to something with the fluid coupling being the problem. If the engine was dyno’d that should rule out any problems there. An improperly repaired coupling could cause vibrations. 

[grandpas50dodge]

@Doug&DebI'm not entirely certain - I think my grandpa may have jumped the gun and decided to replace it as long as the engine was out - I will update as soon as I hear back. I believe he still has the original in his possession, fortunately. 

Edited September 6 by grandpas50dodge

[Doug&Deb]

It’s labor intensive to change but after everything that you’ve tried why not?

[Sam Buchanan]

I'm more concerned about the pounded out bearings..................

[Doug&Deb]

I agree. That’s got me stumped.

[grandpas50dodge]

@Sam Buchanan & @Doug&Deb I'll be talking to my grandpa soon and follow up on these details - it's possible I misunderstood and that the pounded out bearings were before the motor was rebuilt. 

We live a few hours apart, so I'd asked him to send me a letter - one of the few ways he communicates - reminding me of all the steps he's taken to hunt down the problem, and I did my best to put them in chronological order.

Thanks for your interest - I'm not quite the expert he is, so I appreciate your patience! 

Edited September 6 by grandpas50dodge
grammar

[Sniper]

I think my biggest issue is that if it was the torque converter I could see the rear main bearing being pounded out by vibration but if the front one too I don't know how the torque converter would do that

[Ivan_B]

6 hours ago, grandpas50dodge said:

my grandpa had the motor completely rebuilt and had it dyno'd to confirm no vibrations were coming from the engine

Long story, but I did not understand the problem description, at all

Let us get this straight: the vibrations are coming from the engine bay, at any RPM, yet, the engine was confirmed fine on the stand, some long time ago? Does it vibrate when driving or when it is standing still as well, i.e. is it the engine vibrating or the drive-train?

 

Where do you feel/see the vibration? Is the whole engine shaking, or do you feel it at the steering wheel, etc.? Is it making any unusual noises? Do you have a video recording of the problem?

[greg g]

Has delaminating vibration damper or damaged crank pulley been mentioned.  Failed motor mounts?

Edited September 7 by greg g

[Happy 46R]

No expert on this but could the problem be related to the drive shaft? I recall a thread I was reading some time ago about how important it is to mark the drive shaft's orientation to the transmission and differential so it remains true when removing and reinstalling. Given the new torque converter and transmission rebuild could they magnify the vibration from an out of balanced or twisted drive shaft? Just an idea. Dave

[soth122003]

The driveshaft was my thought after you said the engine was rebuilt and dyno'd. The damper and motor mounts are also a concern, but if you pulled the engine, i would think those things would be addressed during that procedure. As far as the D/S, put the car in neutral and rev. If it vibrates, it's not the D/S. In all the other posts, there is no mention of the D/S being lubed. It could be offset by rotation or it might be worn out needle bearings, causing play and vibes, which just love to travel to other areas, making you think something else is the culprit.

 

Joe Lee

[Ivan_B]

Lots of speculation without clear symptoms... It's like coming to the doctor and letting them guess what you came for 😂

[DonaldSmith]

I see it as a mystery, awaiting more clues.  Grampa's car is not at hand.  He can go see it next with a list of possible culprits.  Then he can return with updated clues.     

[QEC]

For those folks who don't bother to read the OP's entire post...

The vibration is felt throughout the vehicle when running - regardless of whether it's in gear or not - and is worse at higher rpms.

Years ago, when it started leaking oil from the rear main seal, he discovered that the rear main bearing had been pounded out. 

That prompted him to purchase a rebuilt fluid drive coupling, but after installing, the problem was worse.

He then thought it might be the camshaft - so he had the engine pulled and had the one from his parts car rebuilt and installed. The rebuilt engine was dyno'd and is perfectly smooth. 

It seems like we've isolated the source of the vibration to the fluid drive

 

So, I'd agree that the fluid coupler (not a torque converter) bears some additional inspection and, especially, the clutch package. Perhaps the replacement coupler did not have a pilot bushing...? I'd also certainly look at the original to check for signs of abnormal wear.

[Ivan_B]

8 hours ago, QEC said:

The vibration is felt throughout the vehicle when running - regardless of whether it's in gear or not - and is worse at higher rpms.

Thank you for pointing this out. Do you suppose the author means that the vibration is felt when the engine is operating or the vehicle is moving? The discussion of being in gear versus not being in gear could mean either way, couldn't it? The phrase "felt throughout the vehicle" is also somewhat ambiguous. I still stand with my original opinion - not enough information, sorry

Edited September 8 by Ivan_B

[Plymouthy Adams]

it has been said a number of times that rebuilding these couplers is not quite the art and success story of rebuilding a torque converter,  odds are your very source of vibration can be traced to the coupler.  

[Sniper]

I appears that the vibration was there with the old coupler and got worse with a new one?

 

Now I know little about these couplers, but I do know torque converters are balanced, I wonder if that was skipped or the balance weight got knocked off? 

 

 

[Plymouthy Adams]

I read the above as the original coupler when going south with vibrations and of course other degrading driving actors, called for the eventual replacement of the coupler.  Then the replacement coupler (rebuilt, usually incorporated splitting the unit and welds)  correct a majority of the issues but had internal issues which well are balance related and how long this unit will survive before imbalance will cause accelerated damage is anyone's guess.  Finding a used donor that has not been cut, welded, etc with install of a new graphite given the bellows are solid would be priority one and likely the most cost advantageous.  Second only to quality replacement original would be the elimination of the coupler itself going to strictly manual clutch only which would make the driving experience less desirable to most every owner.