need some help on vibration issues..

[rover67]

so how many people just live with it? anywon car to do a ride along to tell me if I am being too picky? i just want to make sure it dosen't have a vibration that causes damage..

 

[Uncle Ben]

so how many people just live with it? anywon car to do a ride along to tell me if I am being too picky? i just want to make sure it dosen't have a vibration that causes damage..

Is it harmonic or do ya just feel it?

 

[60wag]

What year is you're 60? Does it have the front shaft CV joint?

 

[rover67]

its an 85.. it has the front driveshaft with u joints. it is pretty shaky. i mean what i am thinking is the rear end just wasn't set up right... but i dont know.

 

[rover67]

well, looks like everything is pretty tight. I may shim the rear axle to see if it helps, but i am just thinking i may leave it the way it is and forget about it. thanks for all the insight and the greetings though!

 

[rover67]

ok, drove quite a bit in 4wd this past weekend. there is definitly a problem with the transfer case. I get a CRAZY vibration on decel from anything above like 20mph when the thing is in 4wd and the hubs are locked. with it in 2wd and th ehubs locked it vibrates, but i have decided it is a livable amount. I will probably drive it for a while like this avoiding 4wd at higher speeds untill i get a chance to take the transfer case back apart..

 

[leiniesred]

vibes

My truck isn't stock, and I've had it long enough to try lots of things.
Driveline vibrations certainly are speed specific and probably what you are dealing with. I doubt your diff setup is bad since you drove it so far already.

Step 1 verify driveshaft phasing. The Y parts of the yolks should match. So the ones welded to the driveshaft and slip yolk should be exactly the same. I have a feeling your FRONT problem is driveshaft phasing going by how severe it seems. It is easy to be off a tooth on the driveshaft and it "looks" right until you put the shaft on the ground.

While you have it down on the ground, go have it balanced. maybe you knocked off a weight on a rock?

Still working on the front...The only thing that can be wrong with the t-case is wobbly output bearings at the t-case. I kinda doubt this because if the bearings are this beat, they leak like the Exxon Valdez. EZ to check. just lever on them up and down. On my mini truck, it is easy to change only the front output.

Uncle Ben already described the angles thing. Basically, with single u-joints on each end, the flanges need to be parallel for smooth operation. Remember, with leaf springs there is some axle wrap under "normal" driving so you tend to "pre-tilt" the rear down about 1/2 to a degree or so. Oon the front, caster is WAY more important for day-to-day use.
Get the caster where you want it first. We'll fix your driveline in a second.

Next up, the "double cardan" you've seen 'em. 2 u-joints back-to-back. UB described these too. Forget the physics arguments. Here is how it works. Point the rear diff flange directly at the t-case flange. Put the double cardan at the t-case end. Single U is all you need at the bottom.

OK. How do you decide which way to shim? Down for parallel? or up straight at the t-case flange for a double cardan? Well, which way is closer? Can you afford to have a double cardan driveshaft built? Want to get the nose of your diff out of the rocks and the driveshaft angles reduced? Don't care that the fill hole is now useless on the diff and the anal retentive will tell you your pinion bearing won't get lubedt? shim the nose UP and get the double cardan shaft under there.

Decision made? Uncle Ben also described how shims are frowned upon. Yeah. U-bolts end up too short on 1 side, e-brake cable runs into the leaves, shims split and spit out....sucks. Here is whatcha do. Do the math as best you can and buy shims as close as you can calculate and estimate. get steel shims only. install and TEST. when you find a shim you like, weld them to your perches. the BETTER OPTION: drop the axle. cut off the original spring hangers and weld on new ones. Rotate the axle housing to the new, optimized and tested angle. now when you bolt it up everything fits right and, "Stock". Cutting and welding hangers isn't a big deal really and the result is much better than an angled shim.

On the front: Run the double cardan. even if you have non-parallel flanges, the vibration won't be as bad.

Happy Trails.

 

[rover67]

ok, i've decided that the rear is fine after lots of driving like you guys said above. totally livable amount of vibration for me... and like spanky said above th ediff seems to be living fine.

so, i pulled the front ds just now to see if th etransfer case output flange was not wobbly and the nut was tight.. they are both fine... as is the pinion flange in th efront. all tight. anyways.. that basically leaves the front driveshaft. It is pretty solid, no weights have been thrown, and after lots of driving around here in the past week in slushy conditions in and out of 4wd with the front hubs locked i have noticed it only vibrates when th ehubs are locked and it is in 4wd and there is slack in the driveline. with just the hubs locked and the driveshaft freewheeling it never vibrates (not even at 80mph).

So, two questions.

one, does it matter if the slip yoke is near the transfer case or near the diff? it was set up near the diff when i got it, so thats how i put it back.

Two, how much slop in the slip yoke is ok? it has a bit of slop (like wiggles in the direction if you were to try and fold it in half) but i dont know if it is too much. it is less than the rear. I am about to go for a drive and see if it makes the same vibraton in 4wd with the driveshaft removed. hopefully that will certianly rule out the transfer case.

also, the shaft is "in phase" as far as i can tell with it out and looking straight down the flanges.

thanks again,

Marco

 

[rover67]

ok, looks like it drives fine with no vibrations in 4wd, so it must be the front driveshaft right? Where do i go to get a double cardan shaft built?

 

[nakman]

ok, looks like it drives fine with no vibrations in 4wd, so it must be the front driveshaft right? Where do i go to get a double cardan shaft built?

Sweet! Sounds like you've nailed it! Boulder Driveline is pretty good, and not too far from you... 47th & Foothills Parkway area.

 

[Uncle Ben]

Sweet! Sounds like you've nailed it! Boulder Driveline is pretty good, and not too far from you... 47th & Foothills Parkway area.

I don't think Ron has parts to make up a Cruiser DC. If you took him one from a FJ-60 he could rebuild and balance it for you. Nak is right on about Rons work....top notch and fast!

 

[rover67]

i have the one that came out of the truck, so i guess i can just take him that one....

hopefully this'll knock it out. thanks for all the help and advice

 

[rover67]

I took the front shaft to ron at lunch and he said the slip yoke was pretty wobbly. also mentioned that the front half of the slip yoke (female part) looked t be pretty long for a toyota of that year. weird.

anyways, he's looking at it and will probably have an estimate for a rebuilt one tomorrow i'd guess.

Also, he said with the amount of lift on my truck (ome heavy heavy) the double cardan might not be neccesary.

jeeze it'll be nice when this is fixed.

 

[Uncle Ben]

Ron is awesome! You will be impressed!

I took the front shaft to ron at lunch and he said the slip yoke was pretty wobbly. also mentioned that the front half of the slip yoke (female part) looked t be pretty long for a toyota of that year. weird.

anyways, he's looking at it and will probably have an estimate for a rebuilt one tomorrow i'd guess.

Also, he said with the amount of lift on my truck (ome heavy heavy) the double cardan might not be neccesary.

jeeze it'll be nice when this is fixed.

 

[rover67]

yeah, i got that feeling talking to him.. i am excited to see what he builds, but not too excited about paying to have it done (this is the kind of crap yo ukick yourself for.. getting it done halfass then having to do it again)... but i guess she'll be right this time, which is sweet it will be worth it.. the sliders are farther out than i thought.

i am tempted to take him the rear shaft since the front shaft that was supposedly rebuilt he said was worn out. lets see how that front turns out.i have high hopes!!

 

[Uncle Ben]

yeah, i got that feeling talking to him.. i am excited to see what he builds, but not too excited about paying to have it done (this is the kind of crap yo ukick yourself for.. getting it done halfass then having to do it again)... but i guess she'll be right this time, which is sweet it will be worth it.. the sliders are farther out than i thought.

i am tempted to take him the rear shaft since the front shaft that was supposedly rebuilt he said was worn out. lets see how that front turns out.i have high hopes!!

Ron is very honest and he doesn't price gouge so what you'll get back from him is indeed what needed to be done!

 

[rover67]

oh, no.. dont take it that way. i trust he will charge whats fair. in fact, i wouldn't mind paying a premium for having that ds perfect.
again, i am excited to have him working on it.

 

[PatrolMan]

Anyone who needs a driveshaft shop on the South side of town, I can't say enough about Englewood Driveshaft. They are located near Hampden and Broadway. My dad has taken in multiple Toyota shafts. Happy with them each time and for a reasonable price. Usually no charge just to look it over and give them a feel. PM me if you need directions or anything.

 

[rover67]

ok, on the bright side of things... I know the front driveshaft is perfect.

on the not so bright side of things, the vibration is still there.

I wonder if I should try to disconnect the rear drive shaft, put the front on jackstands, and spin it up and see where the vibration is coming from.

or maybe i can hire a midget to hang on underneath the truck.

 

[subzali]

Another one from Mark Whatley: May/June 2005 Toyota Trails

"I live in Richmond, CA. I have a rebuilt 1978 FJ40. I love this vehicle and have owned it over 10 years. Bought it off my friend who bought it brand new off the lot in 1978 in New Mexico. It's my peace of mind at night living on the Hayward fault. Over the last 7 years, I've had it customized by a specialty shop in Concord, CA (Chevy V8, power steering, higher suspension, bigger tires). He's extremely talented but we've run into a problem he can't seem to figure out and thus this email. In 4-wheel drive high and low, when you let off the gas there's a horrible vibration noise, but only when you let off the gas and only when you're in 4 wheel drive. It's coming from the front end and Ron has changed out almost everything in an attempt to track it down without any luck. Unfortunately, I'm not a mechanic so I can't really offer him any advice, so I decided to try doing some online research and that's how I found you. If you have any suggestions, it would be most appreciated." Cathy Stonehill

The most likely source of this vibration is an out of phase driveshaft. Both ends of the driveshaft need to be in line with each other. It is common for people to accidently misalign them by 90 degrees if they don't look carefully during reassembly. It is also possible to misalign them by differing amounts if you get careless. The next most likely reason is misalignment of the flanges at each end of the shaft. The faces are supposed to be parallel. Changing of drivetrains, modification of suspension and other similar undertakings can result in inadvertent modification of the relationship between the flanges. You can get away with a small amount of misalignment, on the order of 2-3 degrees. Any more than that causes the type of vibration you mention.

The reason behind these potential causes of vibration is that a u-joint does not transmit the rotation smoothly when it is deflected. The deflection creates a situation where the constant speed that is input to the assembly is changed into a cyclic speeding and slowing scenario. The output from the assembly speeds and then slows twice for each revolution. The greater the deflection, the greater the difference between the fast and slow speed. When all is working as intended, the u-joint assembly at the other end of the shaft receives this pulsing input and changes it back to a smooth output on the other end. For this to happen correctly, the u-joints have to be aligned so that they are trying to pulse in phase with each other. They must also be deflected by the same amount so that the pulse is of the same amount. Any difference in the timing or the size of the pulse creates vibration.

Less likely to produce a severe vibration but a possible source is a very worn pinion bearing (differential) or output bearing (transfer case). A bent or even dented driveshaft can also cause this. But I would look to an out of phase (driveshaft ends) or an out of alignment (flanges) condition.

While I'm thinking about it, an "out of balance" is seldom really the problem. If a driveshaft is straight, as it is supposed to be, it does not need to have weights added to it to "balance it." The purpose of weights is to compensate for slightly less than straight shafts. A shaft that is not straight will vibrate. The weights will dampen this out and offset it due to the vibration they cause themselves. While this makes sense for a factory that is turning out thousands of driveshafts a day, there is no reason that any shaft that is custom made or modified for your rig to need any weights. It is supposed to be straight. Insist on it when you have a shaft made (or lengthened or shortened).

I'm betting on a bad output (t-case) bearing myself, considering mine is more of a growling anyway...