Update: 5.29 gears+4" lift=vibrations due to gears?

[4WD Toyota Owner Magazine]

Update to the pre-Cruise Moab situation--put in Yukon 5.29s, got a grinding noise, replaced all 4 u-joints with OEM Toyota, balanced front shaft, noise still there, worse with front shaft in, less with out. Had the front diff opened and inspected today--report card came back clean! All appears well.

There's are several good threads on lifts and vibrations, but in this case...

What is a little different is that after I installed the 4" Man-A-Fre drop bracket lift kit and drove it first to Surf N Turf and then back to Seattle (over 1000 miles), there wasn't a hint of this noise. Ever. Ditto during subsequent wheeling.

Then I put in the 5.29s and it started one minute out of the garage.

Now, somewhere in that trip from LA to Seattle I assume the driveshaft(s) hit the same RPMs as with the new 5.29s, at some speed. Understanding that the 5.29s are massively different than the 4.10 stockers. I'm a little amazed that 5.29s would immediately "bring the noise" when 4.10s driven from 0 up to 95mph (ask me how I know) never once caused such a noise.

In the end, lesson APPEARS to be that gears, in my case, more than the lift itself can cause a driveline noise to appear through different harmonics or plain driveline rpm speed changed? I'm no harmonic physicist, of course. That's based solely on the fact that 1000 miles of freeway and slower driving with 4.10s and 4" lift caused no noise, but one minute with 5.29s did (30 mph, 44, 62).

Of course, I could be totally off on this whole thing.

Next steps: balance rear shaft. Drive test. Then try the adjustable upper arms for shizaks and giggles. Then go DC shafts.

An interesting saga that I know from other threads has been studied extensively, yet most of those are about the _lift_ being the root of the cause for the most part.

 

[bandy rooster]

is there alot of heat in the diff after driving?

you know theres a break in period for gears? usually 500 miles of light driving.

 

[DirtyHarry]

balanced front shaft, noise still there, worse with front shaft in, less with out.

That should be very telling right there. I would think that the problem is downstream from the front output of the transfer case.

I'm a little amazed that 5.29s would immediately "bring the noise" when 4.10s driven from 0 up to 95mph (ask me how I know) never once caused such a noise.

In the end, lesson APPEARS to be that gears, in my case, more than the lift itself can cause a driveline noise to appear through different harmonics or plain driveline rpm speed changed? I'm no harmonic physicist, of course. That's based solely on the fact that 1000 miles of freeway and slower driving with 4.10s and 4" lift caused no noise, but one minute with 5.29s did (30 mph, 44, 62).

I agree with your assessment David. If you noticed the vibration at certain speeds or RPMs with the new gears I would look for a suspect u-joint or driveshaft, but not at every speed in every gear.

Next steps: balance rear shaft. Drive test. Then try the adjustable upper arms for shizaks and giggles. Then go DC shafts.

It seems like you are just throwing money at the problem. If the problems started when you regeared (not when you lifted) I don't see how adjustable arms or CV driveshafts are going to solve the problem. What was inspected? The pattern? They bearings? I assume that the rear was regeared at the same time, was that diff checked?

 

[landtank]

i'm surprised you didn't have issues right out of the box with the lift. Reguardless of how you correct for caster, if the end result is the same then the potential for vibs are the same.

Keep us posted on how things work out.

 

[Nay]

Diff gears don't just change the downstream. They change how your transmission shifts, how your engine revs, all of which changes how power is delivered through the driveshaft to those very gears.

Your rig has never been at the RPMs it is right now within the shift and torque curve points, all to turn large tires. You have changed the pattern entirely. All of your stuff that worked its way into a 4.10 pattern over all those years may be "resisting', and quite frankly, you can't assume that you haven't exceeded the driveshafts' tolerance limits.

That is why this is not about RPM's that your rig has seen before, because RPM does not cause driveline vibration unless you are exceeding the tolerances of your driveshafts (which you may well be, in which case your tube is actually flexing).

Bottom Line: 5.29 gears are very low, and I think you need a driveshaft upgrade on both ends to handle them. I imagine it is pretty rare to find anybody on 35" tires with 5.29 gears running around on stock driveshafts for very long. And from that perspective, you should have felt it on mile 1 just like you did as a fairly logical cause and effect.

Just make sure that what you buy is built for your usage...higher highway speeds may be out of the question entirely with these gears.

Next question is whether you have spare axle shafts

Nay

 

[DirtyHarry]

Your rig has never been at the RPMs it is right now within the shift and torque curve points, all to turn large tires. <snip>

That is why this is not about RPM's that your rig has seen before, because RPM does not cause driveline vibration unless you are exceeding the tolerances of your driveshafts (which you may well be, in which case your tube is actually flexing).

Nay I am confused, what sort of "driveshaft upgrade" are you recommending? Thicker wall tubing? CV at one end? If the shaft was balanced and fitted with new u-joints I would think that it could be eliminated as the source of a problem that is present at all speeds and RPMs.

 

[clownmidget]

I think Nay has it. With tires in that size range - 315's (which likely aren't a true 35" diameter) - and the 5.29's your driveshafts are just spinning a lot faster than "normal". Adding the increased suspension angles just adds to the probability of getting some vibrations and/or noise at some point.

I've got the 4.88's a front cv driveshaft and with the 315 BFG AT's I can no longer go above 95 without some disconcerting driveshaft vibrations. I haven't pulled the front driveshaft to test it but I bet it's all in it and not the rear. It is interesting that no matter how you deal with the caster issue it seems to produce a driveline issue.

For what it's worth, my problems go away with the 37's so maybe your tires just need to get bigger

 

[4WD Toyota Owner Magazine]

That's what's driving me nuts. I said the same thing to the shop who checked it, the EXACT same thing, but they maintained it was the driveshafts. They (Randy's) said front diff was spot-on. Did not tear down the rear diff--yet. It sure SEEMS to be the gears but, Nay makes some good points about that too.

For what it's worth, my problems go away with the 37's so maybe your tires just need to get bigger

Ha! Yep, I was thinking the same thing!

Thanks for the info everyone. Heat: on the way to CM with just the rear shaft running the transfer case was getting hot. You could smell that "hot" smell and feel it. I stopped and checked the T-case oil level; it was fine and oil looked good.

Hey Nay, clown runs the CV style shafts, do you reco CV or double cardan? Slee has double cardans on his site; that may be where I'm headed after some more testing...

I do have spare axle shafts, actually, for the fronts, plus spare birfs.

Will keep you posted on this. As always, Mud comes through with great input!

Dave

 

[landtank]

a cv shaft is only better in certain applications where it is needed. It's not an accross the board better shaft for all trucks.

You need to start taking some drive angle measurements or you'll join Shotts in the rubber room before you are done.

 

[DirtyHarry]

I think Nay has it. With tires in that size range - 315's (which likely aren't a true 35" diameter) - and the 5.29's your driveshafts are just spinning a lot faster than "normal". Adding the increased suspension angles just adds to the probability of getting some vibrations and/or noise at some point.

I've got the 4.88's a front cv driveshaft and with the 315 BFG AT's I can no longer go above 95 without some disconcerting driveshaft vibrations.

Your problem is different though. David states that his problem occurs at a variety of speeds, slow and fast. I would think that rules out problems related to spinning higher RPMs after the regearing, particularly since the front driveshaft was just rebuilt with new u-joints and balanced.

 

[Nay]

Nay I am confused, what sort of "driveshaft upgrade" are you recommending? Thicker wall tubing? CV at one end? If the shaft was balanced and fitted with new u-joints I would think that it could be eliminated as the source of a problem that is present at all speeds and RPMs.

Double cardan and a necessary level of tube thickness/design/composite (the driveshop should be the expert here). While it may make sense to think you can put on new joints on a standard driveshaft, there is a point where you have simply overly stressed the underlying design of the system. There is a reason that people move to double cardan style shafts beyond angles...they just run cleaner on highly modified applications and they are more durable. It is simply money well spent.

Let me give you a good example of where theory and the real world collide. I once worked with Tom Wood @ 4x4shafts on a driveshaft with double cardans on both ends. This was potentially "the" cure for pinion vs caster angle because in theory with a DC on both ends the driveshaft angles no longer need to share a relationship on each end. Just leave pinion low and let the DC cancel out any angles internally, and then let the t-case end do the same.

Tom agreed in advance to a full refund if it didn't work. The rig was undriveable. Tom had no explanation why...it just didn't work. But it should have. And I got my money back.

I've never heard of any true CV application being terribly strong, but that is a terribly generic statement. DC is a tried and true application in the highly modified dual purpose market. You want to run the low gears on the lift and this is just a natural upgrade.

Here is the short version: if you want to run a good sized lift and 35" plus tires with very low gears you should upgrade your driveshafts. When you read it this way, it is common sense and needs not be over thought.

Good luck with it. Do those 37's and then you'll really want the upgraded shafts to handle the tires

Nay

 

[Tools R Us]

Double cardan and a necessary level of tube thickness/design/composite (the driveshop should be the expert here). While it may make sense to think you can put on new joints on a standard driveshaft, there is a point where you have simply overly stressed the underlying design of the system...

Have you ever had a LC joint apart? They are the finest joints I have ever seen in a stock vehicle, surpassing most of the aftermarket "heavy duty" joints I have worked on. They have inside clips, teflon alignment shims holding the needles in line, triple lip seals and awesome fit and finish.

Where is he "simply overly stressed the underlying design of the system"? He said it ran smooth to 95 mph with the 4.10s and now he gets vibration as low as 30 mph. I'm willing to bet the rpm and torque load is higher at 95 mph with the 4.10s than at 30 mph with 5.29s?

...There is a reason that people move to double cardan style shafts beyond angles...they just run cleaner on highly modified applications and they are more durable. It is simply money well spent.

More money spent doesn't always equal better setup! Double cardan shafts are slightly more forgiving in setup geometry, but they are not a miracle cure and will vibrate just as bad as a single if not setup properly. Double cardan shafts are less reliable than the same size/spec single due to the extra parts, 4 more yokes to wear, one more joint to wear and a pain in the a$$ centering assembly to wear and break. A properly setup single shaft will always be more durable, reliable and require less maintenance, due to it's simplicity and lighter spinning weight. IMHO DC shafts are a necessary evil for when it's not practical to correct the geometry, not an automatic "upgrade" for every "highly modified application".

Let me give you a good example of where theory and the real world collide. I once worked with Tom Wood @ 4x4shafts on a driveshaft with double cardans on both ends. This was potentially "the" cure for pinion vs caster angle because in theory with a DC on both ends the driveshaft angles no longer need to share a relationship on each end. Just leave pinion low and let the DC cancel out any angles internally, and then let the t-case end do the same.

Tom agreed in advance to a full refund if it didn't work. The rig was undriveable. Tom had no explanation why...it just didn't work. But it should have. And I got my money back.

Agree, sometimes you have to step out of the box.

I've never heard of any true CV application being terribly strong, but that is a terribly generic statement.

I agree, they aren't as reliable.

DC is a tried and true application in the highly modified dual purpose market. You want to run the low gears on the lift and this is just a natural upgrade.

Why? If his setup requires a DC shaft then fine, but why would it be "just a natural upgrade"?

Here is the short version: if you want to run a good sized lift and 35" plus tires with very low gears you should upgrade your driveshafts. When you read it this way, it is common sense and needs not be over thought.

Good luck with it. Do those 37's and then you'll really want the upgraded shafts to handle the tires

Nay

The front shaft joints are smaller than the rear, the same size as the Taco's, 4runner's, Tacoma's, etc. I see plenty of them with 35's, 37's and 40's getting beat HARD on the rocks around here, most with stock joints and minimal failure. How many trucks on this board get wheeled hard with big tires and stock joints with 100K+ miles? Do a quick search and see if there is an epidemic of broken joints or shafts? I'm sure if there was we would know about it!

We aren't talking about some heep here, a Land Cruiser comes off the showroom floor with robust, durable parts, mostly ready for the trail, without needing many "natural upgrades"!

 

[Nay]

Have you ever had a LC joint apart? They are the finest joints I have ever seen in a stock vehicle, surpassing most of the aftermarket "heavy duty" joints I have worked on. They have inside clips, teflon alignment shims holding the needles in line, triple lip seals and awesome fit and finish.

Where is he "simply overly stressed the underlying design of the system"? He said it ran smooth to 95 mph with the 4.10s and now he gets vibration as low as 30 mph. I'm willing to bet the rpm and torque load is higher at 95 mph with the 4.10s than at 30 mph with 5.29s?

We aren't talking about some heep here, a Land Cruiser comes off the showroom floor with robust, durable parts, mostly ready for the trail, without needing many "natural upgrades"!

I always enjoy the "you are wrong because it is a Toyota" argument

I agree completely with that last sentence...until you lift said Land Cruiser, in which case that statement is completely irrelevant in terms of driveshaft operation.

There is more to a driveshaft than the joints, and you get over 3 degrees of operation in a u-joint and you begin to shorten useful life. Add very low gears and large tires to those angles and we can talk all we want about Toyota build...all parts have operating limits where they are likely to see excess wear.

The more a u-joint moves in an elliptical arc due to increased operating angle (the arc increases with angle), the more it wears, and hauling a big heavy driveshaft around in said elliptical arc probably isn't the best thing for any and everything it is attached to. See the picture below and then think about your rear driveshaft at high RPM moving in that arc and now spinning faster than it used to, and this is what I mean by "over stressing the system".

For all we know, the lower gears have exposed a bearing problem that has nothing to do with the joints themselves, but has been caused by how those joints have been operating (at 95 mph no less).

So yes, taking a long, heavy, elliptical arc travelling u-joint driveshaft and replacing it with a DC shaft that moves in a pure circle is a "natural upgrade" to fix an undesirable operating parameter in a critical system. This is the idea of "constant velocity". In order to move in an ellipse, the driveshaft has to speed up and slow down with every revolution...that's what you hear as a harmonic vibration when your angles are off.

One other thing according to a formula I just found to calculate driveshaft RPM:

Stock 31" tires with 4.10 gears, RPM = 2,667 RPM @ 60 mph

With 35" tires and 4.10 gears, RPM = 2,363 @ 60 mph

With 35" tires and 5.29 gears, RPM = 3,048 @ 60 mph

35's with 5.29 gears is spinning your driveshafts almost 400 RPM over stock @ 60 mph.

But hey, as long as you use Land Cruiser u-joints...should be no issues at all...

Nay

 

[Tools R Us]

I have never seen a bracket corrected lifted 80, so I can only guess at the geometry, it may be a little high for a CV shaft. So there are two ways to tell if this "natural upgrade" may work for you; Get an angle gauge and measure your driveline angles, this would be a good data point, haven't seen this posted for the MAF kit. The other would be to swap in a CV shaft, if you have one available and see if it helps?

Update to the pre-Cruise Moab situation--put in Yukon 5.29s, got a grinding noise, replaced all 4 u-joints with OEM Toyota, balanced front shaft, noise still there, worse with front shaft in, less with out. Had the front diff opened and inspected today--report card came back clean! All appears well.

Define "a grinding noise", is it steady or oscillate with the truck at a steady speed? What speeds is it the worst? Do you hear it over a big range or only at some speeds? With the power on or coasting? Do you feel it in the truck, if so where? Did the new joints and balance job change it, even slightly? Were the old joints bad?

The "worse with front shaft in, less with out" clue, along with it running smooth before the gear change leads me to believe that it doesn't originate from the shaft. It sounds like an axle problem and the torque load with the shaft installed makes it louder.

What did the gear installer tech say about it? Did he measure the ring gear run out? Is the ring gear backlash even at all points around the gear? How much metal was on the magnet when the oil was drained?

 

[montocr]

not diffs

This is absolutely not diff related. Regardless of a "bracket" or "control arm" or whatever you use to correct caster, you can not change caster w/o effecting driveshaft angles unless you cut and turn the knuckles. The stock driveshaft has its limits as far as smooth operating angle that most people do not have problems with at 2" of lift. Having owned 2 of these vehicles with nearly every spring/spacer/controlarm/castorcorrection/adjustable arms, I found that over about 3" you'll need a front DC, and somewhere around 5 + you'll need a rear DC to get rid of the growl/vibes. Many have found that the rear can be adjusted out w/ adj. uppers at 6" ish, but I was not able to on mine. When you have lower gears any angle issues are amplified by the shaft spinning faster. I have spent countless days swapping shafts in/out, adjusting arms, adjusting suspension heght, etc, and this is what I found.

 

[4WD Toyota Owner Magazine]

This is absolutely not diff related. Regardless of a "bracket" or "control arm" or whatever you use to correct caster, you can not change caster w/o effecting driveshaft angles unless you cut and turn the knuckles. The stock driveshaft has its limits as far as smooth operating angle that most people do not have problems with at 2" of lift. Having owned 2 of these vehicles with nearly every spring/spacer/controlarm/castorcorrection/adjustable arms, I found that over about 3" you'll need a front DC, and somewhere around 5 + you'll need a rear DC to get rid of the growl/vibes. Many have found that the rear can be adjusted out w/ adj. uppers at 6" ish, but I was not able to on mine. When you have lower gears any angle issues are amplified by the shaft spinning faster. I have spent countless days swapping shafts in/out, adjusting arms, adjusting suspension heght, etc, and this is what I found.

Ummm, that's all well and good but you're forgetting the one thing I keep saying: I put on this 4" lift, then drove from LA to Pismo to Seattle, and then for about five more months, AND NEVER HAD A DAMN RATTLE OR NOISE OR VIBRATION. Nada. Nothing. Driveshafts: fine. Axles: fine. So the 4" lift, repeat this LIFT never caused a single noticeable noise/vibration problem until...

...I had the 5.29 gears installed, and on the way home from the shop, about 300 feet/one minute out of the gear garage, I first heard the grinding. So what would that make you think was causing this problem?

So...YES, it COULD be the diffs and/or components therein, i.e. pinion bearings, etc. I'm not saying it is. But in the end the noise started one minute after 5.29 gears were put in. I know 5.29s can be "noisy" but this is more than typical NVH.

To answer an earlier post, the noise comes on, usually, at about 40 on up to 55. Usually on coast/off throttle. Bits of it heard at slower speeds, briefly. All new Toyota u-joints and balance f/r did nothing to change it, even slightly.

I'll probably try a DC shaft. If its totally unchanged, I'm back to ring/pinion as likely culprit. We'll see. It makes for a good set of mysteries to solve as we do the stories.

 

[sleeoffroad]

Not sure if this has been asked, but when they did the gears, did they replace all the bearings in the third members?

 

[LukeO]

So, are 5:29's a tad overkill for 35's that see the highway on a regular basis?

I'm still running stockers w/315's. Not wheeling much these days (still stuck in a mold lawsuit over our previous home and paying too many mortgages right now). But anyway, when the time/money is available again and we're not paying an extra mortgage for no reason should I go 5:29's or 4:88's? I will be driving my 80 on the road often/every week, say to Uwharrie occassionally, likely pulling my 40 (sometime in the future) when it's back together with my 80. But, I'm still thinking getting Biggi Sized with Slee's 6" and 36 or 37 Swampers. So 4;88's or 5:29's with those tire sizes for mixed use?
Probably 36" Swampers.

 

[Tapage]

So, are 5:29's a tad overkill for 35's that see the highway on a regular basis?

IMOP to keep close the stock ratio when you go with 315" 4.88 ya know, are more reduction than stock tires and 4.11 but I always keep in mind if you use 315 you got bull bars, winch, hi lift bla bla bla bla .. weight ! and lift ..

So to compensate more lift ( aerodynamic performance ) weight and new tire weight and ratio .. 4.88 .. I thought 315 with 5.29 are much more tough look 8% reduction nothing .. but do great reduction in fact.

 

[Letsgomoreplaces]

gears

4.88s should be fine w/ 35". If running 36 swamper or 37, I would consider 5.29