Mystery vibration at 25 mph can't be diagnosed. It's not the front end!

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If you can't find the B&T (aka "Detroit") joint, you can have a custom driveshaft fabb'ed with a sliding yoke. It was pioneered by Jeep guys which used the same PN (1978 Wagoneer?, I forgot). You can find a post here w/ photos and Spicer PN's. Show it to a drive-shaft shop and ask them to fab one. Have also seen an ebay ad for Jeep guys quite reasonable (~$150), but don't know if it can be leveraged.
 
Update! Owner of shop, who is in his late 50's, is quite good at fixing problems. They assured me that the B&T and U joints on axle look good. They ran up the motor rpm while in neutral and noticed there was a vibration in the motor at a certain rpm. Could it be the harmonic balancer or maybe a cylinder with little compression?
 
It's not the vibration damper. It's almost certainly not a cylinder with low compression (watching the engine is not how to diagnose this), and the B&T is still not diagnosed by looking at it, no matter how many times these guys tell you it "looks good".

If this guy is so all-fired "good at fixing problems"…why hasn't he fixed it yet? Asking for a friend.
 
slantsixdan said:
It's not the vibration damper. It's almost certainly not a cylinder with low compression (watching the engine is not how to diagnose this), and the B&T is still not diagnosed by looking at it, no matter how many times these guys tell you it "looks good".

If this guy is so all-fired "good at fixing problems"…why hasn't he fixed it yet? Asking for a friend.
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Agree with this^^^^^ On this forum, we really want you to get your problem fixed. B&T problem is likely. AS stated above.
 
jeffrey356 said:
Update! Owner of shop, who is in his late 50's, is quite good at fixing problems. They assured me that the B&T and U joints on axle look good. They ran up the motor rpm while in neutral and noticed there was a vibration in the motor at a certain rpm. Could it be the harmonic balancer or maybe a cylinder with little compression?
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Well, 1st, unless the damper ring/pulley has separated from the elastomer & is visibly wobbling not a chance. I assume the belt(s) are still on.............OK OK...!
2nd, even a lowly stock slanty can do better than 25 in 1st gear, shouldn't have to tell someone older than Myself this but...hey! Same shudder @25mph in 1st as 2nd
gear? Is it doing it in 3rd under light accel? Remember, the driveline is most heavily loaded at low speed and accel in 1st gear, the engine is the opposite.
3rd, if the vibe follows engine speed, not vehicle speed.....is the engine original or at least a '67 and down? if not the torque converter may be wallowing in the crank
register as if You search You will find this referenced on this forum a bazillion times...'68 and up cranks/engines need a hub ring to center the '67 & down converter.
Looking good and being good are just like people in real life, not the same things. Re-read My post (20).
 
whitepunkonnitro said:
B&T joints are actually very easy to service once you know how to do it, providing the wear is in the rollers and not in the body itself.
One catch is that replacement boots are nearly completely extinct. Quick, cheap trick is to use a boot from an off-road style aftermarket shock absorber. Most 4x4 shops can hook you up with one.
Cut it to about 8 inches, and feed it through the inside of the B&T body before you assemble the joint
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Hey, whitepunkonnitro, how is the new shop going? weren't you talking about opening a new shop a few months ago?
 
I'll be glad when I get rid of my b&t. I have the drive shaft trans already.
 
Could a loose timing chain be the problem causing the shutter at 20 - 30 mph upon acceleration. The lead mechanic swears it has to be in the ignition. The slant 6 '65 Dart also skips a beat sometimes when accelerating at 50 mph. They have gone through the distributor and made sure it was correctly timed. Pulled the plugs and noticed some gas on them. Could that be symptomatic of a loose timing chain. I have pissed them off telling them to recheck the B&T and U joints for the 4th time. They swear it's not the drive line. If I could afford it, I would have them replace the timing belt/chain. I just can't believe this crap. If only I hadn't broken my back!
 
Maybe a member near you could help out? Come and drive it. Sometimes some of us like payments of beer and mopar talk rather than cash
 
I've ended this madness. At least they finished the brakes, tuned it and swapped out improper length spark plugs for $100. I'll try to take the drive shaft off myself and take it to an expert in the big city. I had to try and have this done because of a bad back, no friends and my wife passed away this year at 40. I'll probably post it for sale. My dreams of complete restoration on disability have blown out of the window. Thanks for all the input. I'll ask $5,500.
 
jeffrey356 said:
I've ended this madness. At least they finished the brakes, tuned it and swapped out improper length spark plugs for $100. I'll try to take the drive shaft off myself and take it to an expert in the big city. I had to try and have this done because of a bad back, no friends and my wife passed away this year at 40. I'll probably post it for sale. My dreams of complete restoration on disability have blown out of the window. Thanks for all the input. I'll ask $5,500.
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Sorry to hear Dude, condolences, that's a tough one. Once You get Your ride home, Deemo's on to something there, sure wouldn't be the 1st time a member has helped
out another! Put out the feelers for someone on this forum, or slantsix.org in Your neck of the woods, can't hurt Man.................
 
Don't sit there and sell your car because of the vibration. Youre letting a hunk of metal win. You can't sit there and let that car go because there's a vibration. If I were near I'd come by and help. There's a huge community here, most of you I'll never meet. But the few I have, have spent hours on the phone. Swapping pictures of car parts, good ol' stories of fun times and the bad. But no matter what, someone would always come by. Offer their opinions and we'd get it fixed. Scour the net, he'll, put up a wanted add maybe??? Maybe they won't take it down. Worst case, swap out that b&t for a regular slip yoke. I got a trans and driveshaft. If you pay the shipping I'll give you a 3 spd if that's what you have. All you'd need is the drive shaft. Surely someone here is close and knows what to look for.
 
jeffrey356 said:
Could a loose timing chain be the problem causing the shutter at 20 - 30 mph upon acceleration
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No.

The lead mechanic swears it has to be in the ignition.
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1. No, it doesn't. There may also be an ignition problem (cars can have more than one problem at a time) but the problem doesn't "have to be" in the ignition.

2. The ignition system on your car is stone-simple. Why is this guy standing there swearing about it instead of fixing it, if he's so sure that's where the problem is?

Pulled the plugs and noticed some gas on them. Could that be symptomatic of a loose timing chain
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No.

I have pissed them off telling them to recheck the B&T
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That's their problem.

If I could afford it, I would have them replace the timing belt/chain
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There is no timing belt. Guessing at random parts to be replaced is a sure-fire way to waste money. If you cool off and decide not to sell the car, step "number zero" (first thing) you need to do is learn how your car works. Get the three books described in this thread and start reading. Otherwise you're going to be at the mercy of clowns like the ones you described at that shop over and over and over and over without end.

I've ended this madness.
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Good!

At least they finished the brakes, tuned it and swapped out improper length spark plugs
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What exactly did they remove as "improper length" spark plugs?
 
Thank you everyone for your support. After sleeping on it, you're right, I can't let a simple vibration make me sell this true survivor with only 44,000 miles on it. Everything is straight on it except the interior is a little tired. But, She's a beauty. Deemo, if you have a trans and will fit my 65 dart slanty, I would be interested in buying it and paying shipping. I need to save up for it first. My 3 spd auto trans slips a little if you don't firmly position the lever on the tree. I'm curious how much you want? I don't know if we can talk prices on the forum. You can private message me at jeffrey356. I will post a wanted drive shaft in the classifieds on this forum.
 
I put E3 spark plugs in it and they were a little short. We just put stock champion plugs in it. Runs great, but a little vibration exists. I'm picking it up on Monday and will start saving up for a drive shaft.
 
This is the 65 dart with the vibration problem. She is worth hanging onto.

20170504_135220.jpg
 
jeffrey356 said:
I put E3 spark plugs in it
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See, this is just one kind of money waste that can be prevented by knowing how your car works. See this thread...and get those linked books!

We just put stock champion plugs in it
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Better than "E3" trinkets, but you can do much better still. Tune-up parts and technique suggestions are in this thread.

I'm picking it up on Monday and will start saving up for a drive shaft.
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No, you're skipping steps. Proper diagnosis is key -- not guessing which part to throw money at next.

Good luck with your car. I hope you get it fixed and learn how it works. I'm done trying to help; you don't listen. ¯\_(ツ)_/¯
 
slantsixdan, I suggested everything you mentioned, but I had supposed professionals telling me that everything you mentioned is not the problem. I was at their mercy because I can't even bend over to load the dishwasher. That's why I ended this ordeal. The mechanics which have 20 to 30 years knowledge threw their hands up and said they just can't diagnose the problem. I started this whole process by just balancing the wheels and inspecting steering linkage. Then it just went from one thing to another. Nothing inspected turned out to be the problem. If mechanics with that many years of experience are baffled, how can I argue the fix. When I get it back, I plan to basically start over. Everyone is telling me that it's the B&T drive shaft. My bill would have been hundreds and hundreds of dollars if I just bought parts and stuck them on. The shop went from one inspection to another without buying parts. The only thing I bought was spark plugs and labor. My dodge dart technical manual from that year shows the proper inspection of a timing chain. Now, you're telling me there is no timing chain? I throw my hands up. Totally confused at this point. That's why I'm thinking about selling. I'll wait for 6 months to make my decision. I've just been told so many things and yet supposed pros tell me the opposite. UGH!
 
I thought you told me to start with B&T, so that what I was going to do and now you say I'm skipping steps. I'm confused?
 
jeffrey356 said:
I thought you told me to start with B&T, so that what I was going to do and now you say I'm skipping steps. I'm confused?
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He told You to focus on diagnosing the B&T good or bad. As has been posted by another member, adding a stack of 3-4 flat washers on each bolt between the trans flange
& joint will change the vibe, even if it doesn't disappear, may get better or worse. On a related note, exactly why is the tail of the car so high & what is being used to get
it there? If those are air shocks, let all the air out & test drive it. The B&T doesn't have a ton of travel, surprisingly little travel actually, that ride height ain't doin' it any
favors.
 
The rear end has been that high since I bought it. That was 4 years ago. The previous owner put truck(?) or station wagon(?) leaf springs on it because he said that he couldn't find new ones for the dart. Well, that was the next thing I was going to correct. I found the correct 5 leaf springs from classicindustries. I have had to chase down a ton of parts that were just slapped on it for a quick fix. That is just one example. The dart didn't start shuttering until about 3 months ago, but I will definitely get the proper leaf springs for it as soon as possible. Now I understand what he meant to DIAGNOSE the problem with washers. I told the SHOP to try that and they wouldn't do it. They said that's not a fix. But, I'll have it back next week and I can do what ever it takes as far as diagnostics. Believe me, I can't afford to just slap parts on it. I'll need a crawler first and maybe I can do it. I still have the physical limitations to deal with. If the washer diagnosis works then I'll know what the problem is and what I have to do to fix it once and for all. This has all been a nightmare because basically, I have just been the messenger. Each message I pass onto the shop, gets shot down. I couldn't just go out to the garage and try the possible solutions mentioned myself. I'm only out $100. That's labor, spark plugs and a whole lot of grief.
 
I have a bolt on, non-B&T driveshaft that was on a 65 Dart that I used to own. I changed to a layer engine and trans in the car before selling it. If you were closer, I would give it to you to try out.
The rake is a lil much, but why not lift the front end a bit by adjusting the torsion bars to see if that helps. The front seems low.
 
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