I have a 77 Pinto sedan 2.3 & at 55-65 it vibrates from the back something fierce. I thought it might be the gear so I got a replacement & took the old one out, but there doesnt seem to be any excessive wear. I did notice some wear to the axle shaft splines though. Could that be my problem? If not what? I already replaced the u joints so that is all good.
HELP!!!! Need it ready for Carlisle!!!!!!!!!!
Check the rear tires for out of roundness and balance.
Quote from: pintoman on May 29, 2006, 01:27:40 PM
Check the rear tires for out of roundness and balance.
Good tip. Usually the drive train does not cause a car to vibrate.I would go with the tire/wheel combo first and check it out.
I actually replaced the tires & they're all good. I may have been describing it wrong. Its a vibration but it's a driveline vibration, like I'm dragging my butt on the ground. Sounds like a groaning noise from the back as opposed to a tire vibe.
Is the pinion gear torqued to spec's.
Not too sure if it was or not. I got it all apart & will be installing the replacement parts into the housing. Hopefully all will be good once I get it all together.
Wel, I did a test fit & found the replacement parts do not fit the housing on my car. After finding that out I took a look at the old ring & pinion & there was no unusual wear to any of the teeth. with that in mind could it have been a bad pinion bearing? It did have some play so I replaced that.
Any ideas?
How about the axel bearings???
You might want to check the driveshaft closely to see if you can tell if it has lost a balancing weight, and that it is installed in the original assembled position relative to the front and back yokes. On a vehicle this old, it would not be unheard of to have suddenly lost a weight, which would definitely cause a driveline vibration.
If, as you said, one or both of the u joints were replaced recently, the driveshaft may have been incorrectly indexed during reassembly, which could easily cause an out of balance condition. That's why the procedure is to mark things before disassembly. Did the problem get worse or start AFTER doing the u joints?
If you haven't done so yet, don't forget to double check that the ujoints are assembled and installed correctly, sometimes crud or rust gets trapped in the bearing cup recesses and then the new joint doesn't settled in properly.
Also, did you tap the new ujoint with something like a deadblow hammer, after assembling it to the driveshaft, to see that it rotated smoothly and not stiffly? Not doing this during reassembly, to make certain that the needle bearings are free, and that the spider is centered, and that the NEW ujoint is truly free to move properly is frequently a cause of sudden onset driveline vibration.
I think you might have hit on something. I did not index the driveshaft when I replaced the u joints. What made me think it was the rear gear itself was I wa getting a single clunk when I put the car in gear. Now I'm not so sure it wasn't something else besides the gear.
Pintony, I checked the axle bearings & they spin freely but not too freely. I think what I'm gonna do is reassemble it all after cleaning it & relubricating all necessary parts & change the position of the driveshaft to see if that makes any difference at all.
How should I lubricate the bearings? With grease or what? I have bearing grease, but don't know if I should use it on the axle bearings & such. Also what is the torque spec on the pinion gear nut?
I too am having the same problem. Mine is more like a whole car viberation though. Its wierd though. When it starts to vibe, If I let off the gas it stops it is only when I give it some throttle at those speeds?
It is fine when I am getting up to speed but when I get to about 55-65 it starts to shake. It kinda dies off when I get to 70.
I know its not the tires, But I know I have a bad shock, I am going to replace them and see if it helps.
could it be alignment?
Matt (and others),
You might want to check YOUR ujoints to see if one is sloppy. A couple of tips:
Grab the driveshaft in one hand and hold onto the yoke with the other, you should not be able to feel or hear any "clunk" or "click" between these 2 parts at all if there is no wear to the joint and sufficient lubrication is present. If you CAN, it's time to replace the joint. Don't just grab the driveshaft and rotate it without holding onto the yoke, or you will simply be feeling the significant amount of play that is almost always going to be present in the differential and/or the transmission.
The most common cause of wear to a ujont is lack of lubrication. Many modern ujoints are "sealed for life", and those that aren't frequently get ignored when a front end lube is done. Without regularly replacing the grease that can get forced out over time or contaminated with road dirt bypassing deteriorating seals, the joint will eventually hit a point where there is metal to metal contact between the needle bearings and the spider. (Also, any space that is not occupied by grease is an open invitation for water to enter the joint through condensation or direct exposure.) Either or both can wear to a flattened condition, and over time that creates a lot of extra movement that is not supposed to be there inside the ujoint.
Many times when there is enough wear in a ujoint, it can come to rest in an off-center position, and it can then produce a whole vehicle vibration when the driveshaft rotates-IF it remains in that off-center position. Then, when you bring the car up to speed, it will sometimes find a high enough speed at which it may recenter itself.
Matt, I think that may be what is happening when you get up to 70.
Until then, the transmission is shifting every few seconds (or more often) and because of the short time involved, and the continually changing torque pressure being applied to the joint as you accelerate, you may not be noticing the vibration, even if it is there.
At a steady speed while staying in one gear, the vibration would be more liable to be easily noticed.
When you're cruising at a steady speed, or accelerating, all of the slack is taken up from within the drivetrain, as one component steadily pushes against the next, which then pushes against the next, etcetera, until the pressure reaches the axle shafts themselves, which is the end of the line.
But when you back off the throttle and coast, think about what is happening at the ujoint.
1. the joint is relatively slack, and it can "float" between IT pushing and it BEING pushed by the components farther down the line. In this loose state it would not be able to TRANSMIT vibration from it's own unbalanced condition and the mass of the driveshaft may well dampen the vibration completely, even if there is a LOT of slop or a lack of balance in the ujoint.
2. if the driveshaft is rotating fast enough, it may also be able to temporarily recenter itself then when it is not under continuous pressure.
Changing the shocks will not get rid of a whole car vibration if it originates in the driveline. Although it might improve the handling and ride.
r4,
the clunk may well "just" be wear in the transmission. Or an accumulation of wear at several components. (Each ujoint, plus the trans, AND the differential, each having a little could add up to quite a bit and result in a big clunk.) If it isn't acting up otherwise, or getting worse, a lot of people learn to live with a clunk like that. If you've already changedthe ujoints, check for play from the front joint forward, you might be surprised at how much can be there and the trans not having any obvious problems.
P.S. Check your idle speed too. (Here I'm going with the idea that you have automatic transmission.)
If that is higher than it should be, the transmissions' initial engagement is taking place at a higher than designed speed and play or no play, there will be more of a "clunk" or "thud" than there would be if it were slipping into gear at a lower engagement speed. Little stuff can make a big difference....
Wow awesome info there.
I checked my driveshaft for lost weights, but none were missing. I checked to see if my u-joints were bad, but they seemed fine to me. I will have to wait until I am back at my shop to check to see if there is play like you stated above.
I know now that my Front end alignment is off. The inside of the Right tire is almost bald. I think that is my problem there. Or at least a Factor in the problem. I will probably order a new set of bushings and replace them, then have it aligned and see where I need to go from there.
Does anyone know if they make bushing kits for a 74 pinto. Like I know I got like a Energy suspension kit for my rx-7, Do they make something like that for our pintos?
r4,
Unless you recently replaced only ONE of the front tires with one that hasn't been there as long as the other front tire, having only one front tire inside edge being bald is generally not a wheel alignment problem. It's more likely to be a worn, bent, or broken parts problem on only that side of car. (usually from a tie rod end or a bad lower ball joint)
BOTH front tires having only their inside edges being equally bald=wheel alignment problem.
A loose enough tie rod end or any weight bearing ball joint in the steering or suspension can make some cars shake, wobble, or weave side to side, which may be contributing to the whole car vibration problem you described, by amplifying it.
BTW,
Didn't you say earlier in this same thread that "I actually replaced the tires & they are all good." ? Did that one front tire suddenly go bald on the inside edge after you replaced them all?
What's the real story here? It's harder for anyone to help if the info you're supplying is not accurate.
In re. a possible missing driveshaft weight:
It might be very difficult to determine if a weight is actually missing from an old driveshaft, if it has been very slowly peeling off from slowly advancing rust over the years. They are usually spot welded on, and if it DID come off, only one tiny spot may have still been holding it on before it came off.
If the problem started after doing any work on the driveline, I'd suspect indexing as more likely to be the problem.
I think ProThane makes bushing kits for the 74. You might also check your shocks. worn out shocks will thrash your front tires in a hurry.
(And if you can't tell your shocks are gone when driving the vehicle, someone else should be driving it.)
For what its worth, I had a pinion bearing that caused a roaring or groaning sound from the rear end as it was going bad.