Nasty Vibration

95SASMudRunner · 04-01-2006, 09:23 AM

I have a SAS 93 4Runner, when the front hubs are locked i get a horrible vibration (i cant go above 10mph!!!) I had the driveshaft balanced-no help, however the truck can be in 4wd with the hubs unlocked and no problem, moreover in 2wd with locked hubs and have a problem! thus the driveshaft is out of the question. I have check the front diff oil, it is ful and clean... A little piece of history, i had a probelm with one of the hubs engaging... this was thought to be fixed, could that play a role in this? Ideas on fixing it? Also the front has a detriot locker in it aswell...

Thanks,
Andrew

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L33T35T 4Runner · 04-02-2006, 11:23 PM

well if you're in 2wd with your hubs locked, your half-shafts are still spinning your differential, which is spinning your axle. your transfercase and front axle arent connected, but it's still spinning, so it may be an unbalanced axle

marko3xl3 · 04-02-2006, 11:41 PM

Did you try locking each hub seperatly to eliminate which side the vibration is occuring?

Bobakazi · 04-03-2006, 10:20 AM

Sounds like the hubs are having issues. Have you tried rebuilding them? It is not very difficult. First try driving a little with just one hub locked. Then the other. Does it vibrate with only one and not the other?
Also, (I doubt this part) but maybe your Detroit is starting to fail. Does the vibration change at all when cornering?

Elvota · 04-03-2006, 10:54 AM

Whenever hubs are locked... the driveshaft spins, just no load if in 2WD.

Maybe remove front driveshaft completly, would eliminate a possible cause.

Did you have a custom DS made for the SAS? Vibrate from day one of install or after some use?

95SASMudRunner · 04-03-2006, 12:35 PM

Quote:

Originally Posted by Elvota

Whenever hubs are locked... the driveshaft spins, just no load if in 2WD.

Maybe remove front driveshaft completly, would eliminate a possible cause.

Works fine with drive shaft spinning but hubs unlocked so not thinking the driveshaft is an issue moreover a shop balanced it professionaly giving me zero improvement

wrenchmonster · 04-03-2006, 01:14 PM

From your concern on the original post I'd definately take the hubs apart and check to make sure they are okay.

I'd also check the oil in the front diff. What kind of locker in the front? Some are very oil sensative and getting the incorrect type can really wreak havoc.

Are you running different brand or different tread tires front and rear?

95SASMudRunner · 04-03-2006, 01:20 PM

Quote:

Originally Posted by wrenchmonster

From your concern on the original post I'd definately take the hubs apart and check to make sure they are okay.

I'd also check the oil in the front diff. What kind of locker in the front? Some are very oil sensative and getting the incorrect type can really wreak havoc.

Are you running different brand or different tread tires front and rear?

Yes I have checked the oil it is full and looks clean, the locker is a Detroit True Track, the tires are the same front and rear however that brings up a good point the front tires a much more worn than the almost new rear ones, they are 35x15.50 tsl/sx's the hubs appeared fine last tear down with no 4wheeling since....

95SASMudRunner · 04-03-2006, 01:22 PM

Well heres the deal the hubs worked fine one at a time, then worked fine together, the hubs unlocked n truck in 4wd worked fine too, however its when they are both on at the same time i get the problem, locked hubs + 4wd = vibration, one with out the other = smooth

shiftless89 · 04-03-2006, 02:21 PM

maybe you got a bad install on the gears? sounds like its binding?

95SASMudRunner · 04-03-2006, 03:13 PM

wouldnt think so because they turn fine when in 2wd right?

^VooDoo^ · 04-03-2006, 05:26 PM

Just an Idea to check.
I have a simular problem right now and I can tell what it is on mine, Yours may be even more serious.
Happens when the hubs locked only no 4x4 but not when unlocked in 4x4.
The shaft and axel need grease, On mine its a High pitch squeal as the axel is viberating in the shaft, Yours may be really dry and chunky from weathering.
Would have been nice if the axel had zerqs in them just for that.
Im going to fix mine as soon as I can find that stupid 2-1/8th socket.

Thats the cause or your locker is binding/fighting between the wheels.

wrenchmonster · 04-03-2006, 05:30 PM

I think the Detroit requires LSD fluid. The vibration you are describing when it's in 4wd and underload is text book wrong fluid. I've seen a lot of this on GM product on rear limited slips where owners or the lube shops don't put in an LSD additive like BG.

For the cost of new fluid, it's worth a shot to change the fluid out and add a LSD additive and keep your finger crossed. Unfortunately, the damage may already be done. Even changing out the fluid may not help. The only way you can tell would be to take the 3rd member out and inspect clutches and clearances.

95SASMudRunner · 04-04-2006, 05:09 AM

Any other ideas?

Bobakazi · 04-04-2006, 09:38 AM

Is this something recent that started happening for no apparent reason and your Truetrac worked fine before, or was there some work done on it and you have the problem since?

95SASMudRunner · 04-04-2006, 12:38 PM

Quote:

Originally Posted by wrenchmonster

I think the Detroit requires LSD fluid. The vibration you are describing when it's in 4wd and underload is text book wrong fluid. I've seen a lot of this on GM product on rear limited slips where owners or the lube shops don't put in an LSD additive like BG.

For the cost of new fluid, it's worth a shot to change the fluid out and add a LSD additive and keep your finger crossed. Unfortunately, the damage may already be done. Even changing out the fluid may not help. The only way you can tell would be to take the 3rd member out and inspect clutches and clearances.

Well spoke with Detroit and this is what they said:

"The 90wt oil is a good choice for a Truetrac, friction additive is not required and should not be used."

He seems to think it is due to the differances in tire wear... i measured from ground to top and only get about 1/2 -3/4 inch differance, he thinks its enough any one else have experiance in this area?

wrenchmonster · 04-04-2006, 08:00 PM

Well, at least you got the fluid concern checked off your list. Yes, tire wear is an issue for 4wd systems. If you really want, you can mark your tire and run a string around the tread and compare the front to rear circumference of the tires. Tread pattern can make a difference, but circumference would be more critical factoring in gear ratios. I think it would be worth a shot and either get 2 new tires, or maybe borrow a whole set from a buddy. Good luck and keep posting once you figure out what happened.

yota_krazy · 04-04-2006, 08:49 PM

you could try rotating your rear tires to the front for diagnostic purposes to see if that changes.

Elvota · 04-04-2006, 11:19 PM

If you find a tire size difference... just drop the air pressure in the larger diameter set. Presto, instantly smaller diameter. Might help you troubleshoot at least.

Bobakazi · 04-05-2006, 12:17 AM

I'm not preaching, just blabbing. The Truetrac is a LSD, not a lunchbox or spool. I can't imagine it would make you vibrate that much with only 1/2" tire difference. I do try and keep my tires rotated, but I know I have had that much of a difference in the past and had no issues. I suppose if you had access to 4 more rims and tires that could be easily swapped for a hot minute, and see if it still occurs, that is what I would do. Or, you could just disconnect your rear drive and drive for a bit in 4wd. (essentially front wheel drive only) Any comment on my last post?

wrenchmonster · 04-05-2006, 02:06 AM

Rotating your tires will not make a difference because you are trying to determine if the varience between the front and rear is the problem. You're not changing anything in the equation. A+B=C or B+A=C ... it makes no difference.

Deflating the tires will also make no significant difference. This is not a rubber balloon we're talking about, it's a tire. Deflating/Inflating will only change the level of the vehicle and the contact pattern with the ground.

A 1/2 inch difference seems small but is deceptively large. You can't think of it like a piece of lumber. If you were to use the string method I decribed above you'd be surprised how much difference a 1/2 inch makes when you compare the two. The two pieces of string will not be different by 1/2 and inch, but maybe more like 1 1/2 inches. I'm no good at math at all, but maybe some of the math gurus will chime in.

Disconnecting the rear drive line will probably work, I just think the tire change is more conclusive since you will maintain load on both axles.

Beyond the string method, you could also get a piece of chalk and mark the tires 90 degrees to the ground. Then drive in a straight line for a while, get out and see where the chalk lines are front to rear.

95SASMudRunner · 04-05-2006, 05:15 AM

Quote:

Originally Posted by Bobakazi

Is this something recent that started happening for no apparent reason and your Truetrac worked fine before, or was there some work done on it and you have the problem since?

It has been a problem since the start, i just have not known as i was dealing with separate issues; i have now resolved, ive got a buddy who im gonna borrow his tires and see how that plays out, i am hoping that this resolves the problem, though the only other issue i have not trouble shot it the front hubs, i suppose it is possible that one is not engaging fully but enought to not cause problems when not under load.

Quote:

Originally Posted by wrenchmonster

A 1/2 inch difference seems small but is deceptively large.

The Detroit guy said anything over 1% can cause problems and by doing the math a 1/2 inch is just over 1% thus if im pushing the 3/4-1" im over. Wouldnt have thought this was true but go figure.

04-02-2006, 11:23 PM	#2 (permalink)
L33T35T 4Runner Contributing Member Join Date: Oct 2002 Location: Fountain Valley, CA (so cali) Posts: 2,005	well if you're in 2wd with your hubs locked, your half-shafts are still spinning your differential, which is spinning your axle. your transfercase and front axle arent connected, but it's still spinning, so it may be an unbalanced axle __________________ 95 4Runner SR5 3.0l. V6 2 wheel drive baby! 31" Bridgeston Dueler A/T Revos. Downey 1.5 Coils. Doetsch MV-12 Shocks. Brembo Rotors. Performance Friction Pads. Pioneer head unit with 1 12" Pioneer woofer. XM Radio. RB Headlight Harness w/ Sylvania SilverStars New to the family: 85 4Runner 22RE, 4x4, 5 spd, SFA. 31" BFG All Terrain T/A KOs, genuine Walmart seat covers, "Dual" stereo, XM Radio, RB Headlight Harness w/ Sylvania SilverStars. Onboard air. Has been seafoamed to hell

04-02-2006, 11:41 PM	#3 (permalink)
marko3xl3 Contributing Member Join Date: Jun 2005 Location: San Jose, CA Posts: 1,709	Did you try locking each hub seperatly to eliminate which side the vibration is occuring? __________________ :Marko: Supercharged 98 4Runner SR5 4x4 3.4L 4" Deckplate :: TrueFlow Air Intake System :: Magnaflow 18" Muffler w/ Resonator XM Satellite Radio (Roady 2) :: Autometer Boost Gauge :: Color Keyed Spoiler TOYOTA\|moving forward

04-03-2006, 10:20 AM	#4 (permalink)
Bobakazi Registered User Join Date: Jan 2006 Location: Portland, OR Posts: 379	Sounds like the hubs are having issues. Have you tried rebuilding them? It is not very difficult. First try driving a little with just one hub locked. Then the other. Does it vibrate with only one and not the other? Also, (I doubt this part) but maybe your Detroit is starting to fail. Does the vibration change at all when cornering? __________________ '90 Extra cab V6 4x4 PU 5.29 gears. Detroit locker front, Detroit Truetrac rear. 35" BFG mudders. Trailmaster 4" susp, 3" body lifts. Add-a-leaf. K+N intake, 2.5" exhaust with Flowmaster 40 and a cat I got off an Evo VIII.

04-03-2006, 10:54 AM	#5 (permalink)
Elvota Contributing Member Join Date: Jun 2005 Location: Phx, AZ Posts: 3,442	Whenever hubs are locked... the driveshaft spins, just no load if in 2WD. Maybe remove front driveshaft completly, would eliminate a possible cause. Did you have a custom DS made for the SAS? Vibrate from day one of install or after some use? __________________ ================ 1990 4Runner \| V6 3.4 \| 5spd \| 240 someoddthousand miles \| SR5 \| SAS \| RLS \| 35's \| ARB \| TJM \| 217 to 1 \| W8000 - four wheels \| three sticks \| two hands \| one trail - RIGITY DIGITY visit the sticki chronicles

04-03-2006, 01:22 PM	#9 (permalink)
95SASMudRunner Registered User Join Date: Jul 2005 Location: Newport News, Va Posts: 257	Update: Well heres the deal the hubs worked fine one at a time, then worked fine together, the hubs unlocked n truck in 4wd worked fine too, however its when they are both on at the same time i get the problem, locked hubs + 4wd = vibration, one with out the other = smooth __________________ 1995 sas 4runner worked on by Cornfed... blew up week later 1993 SAS 4Runner, 4.88s, locked front, TRD e-locker rear with Inchworm kit, 35x12.5 BFG MT's, rock crawling rear bumper, All Pro front tubular bumper with Mile Marker SE12000 winch, Hella 500's, front & rear hitches, sliders, k&n drop in with ARB snorkel, custom duals, Federal Signal siren with whelen red strobes! custom front spring mounts rear susp. added another 2" of susp lift totaling at about 9"

04-03-2006, 01:14 PM	#7 (permalink)
wrenchmonster Contributing Member Join Date: Jan 2005 Location: WA State Posts: 660	From your concern on the original post I'd definately take the hubs apart and check to make sure they are okay. I'd also check the oil in the front diff. What kind of locker in the front? Some are very oil sensative and getting the incorrect type can really wreak havoc. Are you running different brand or different tread tires front and rear?

04-03-2006, 02:21 PM	#10 (permalink)
shiftless89 Contributing Member Join Date: Jun 2004 Location: fairhope, al Posts: 1,321	maybe you got a bad install on the gears? sounds like its binding? __________________ 1989 SR5 V6 5sp 4RUNNER. -> MOST VIEWED 1ST GEN ON YOTATECH! www.toyotatrailriders.com Wheeling Texas Style

04-03-2006, 03:13 PM	#11 (permalink)
95SASMudRunner Registered User Join Date: Jul 2005 Location: Newport News, Va Posts: 257	wouldnt think so because they turn fine when in 2wd right? __________________ 1995 sas 4runner worked on by Cornfed... blew up week later 1993 SAS 4Runner, 4.88s, locked front, TRD e-locker rear with Inchworm kit, 35x12.5 BFG MT's, rock crawling rear bumper, All Pro front tubular bumper with Mile Marker SE12000 winch, Hella 500's, front & rear hitches, sliders, k&n drop in with ARB snorkel, custom duals, Federal Signal siren with whelen red strobes! custom front spring mounts rear susp. added another 2" of susp lift totaling at about 9"

04-03-2006, 05:26 PM	#12 (permalink)
^VooDoo^ Contributing Member Join Date: Mar 2006 Location: Alhambra CA. Posts: 395	Just an Idea to check. I have a simular problem right now and I can tell what it is on mine, Yours may be even more serious. Happens when the hubs locked only no 4x4 but not when unlocked in 4x4. The shaft and axel need grease, On mine its a High pitch squeal as the axel is viberating in the shaft, Yours may be really dry and chunky from weathering. Would have been nice if the axel had zerqs in them just for that. Im going to fix mine as soon as I can find that stupid 2-1/8th socket. Thats the cause or your locker is binding/fighting between the wheels.

04-03-2006, 05:30 PM	#13 (permalink)
wrenchmonster Contributing Member Join Date: Jan 2005 Location: WA State Posts: 660	I think the Detroit requires LSD fluid. The vibration you are describing when it's in 4wd and underload is text book wrong fluid. I've seen a lot of this on GM product on rear limited slips where owners or the lube shops don't put in an LSD additive like BG. For the cost of new fluid, it's worth a shot to change the fluid out and add a LSD additive and keep your finger crossed. Unfortunately, the damage may already be done. Even changing out the fluid may not help. The only way you can tell would be to take the 3rd member out and inspect clutches and clearances.

04-04-2006, 05:09 AM	#14 (permalink)
95SASMudRunner Registered User Join Date: Jul 2005 Location: Newport News, Va Posts: 257	Any other ideas? __________________ 1995 sas 4runner worked on by Cornfed... blew up week later 1993 SAS 4Runner, 4.88s, locked front, TRD e-locker rear with Inchworm kit, 35x12.5 BFG MT's, rock crawling rear bumper, All Pro front tubular bumper with Mile Marker SE12000 winch, Hella 500's, front & rear hitches, sliders, k&n drop in with ARB snorkel, custom duals, Federal Signal siren with whelen red strobes! custom front spring mounts rear susp. added another 2" of susp lift totaling at about 9"

04-04-2006, 09:38 AM	#15 (permalink)
Bobakazi Registered User Join Date: Jan 2006 Location: Portland, OR Posts: 379	Is this something recent that started happening for no apparent reason and your Truetrac worked fine before, or was there some work done on it and you have the problem since? __________________ '90 Extra cab V6 4x4 PU 5.29 gears. Detroit locker front, Detroit Truetrac rear. 35" BFG mudders. Trailmaster 4" susp, 3" body lifts. Add-a-leaf. K+N intake, 2.5" exhaust with Flowmaster 40 and a cat I got off an Evo VIII.

04-04-2006, 08:00 PM	#17 (permalink)
wrenchmonster Contributing Member Join Date: Jan 2005 Location: WA State Posts: 660	Well, at least you got the fluid concern checked off your list. Yes, tire wear is an issue for 4wd systems. If you really want, you can mark your tire and run a string around the tread and compare the front to rear circumference of the tires. Tread pattern can make a difference, but circumference would be more critical factoring in gear ratios. I think it would be worth a shot and either get 2 new tires, or maybe borrow a whole set from a buddy. Good luck and keep posting once you figure out what happened.

04-04-2006, 08:49 PM	#18 (permalink)
yota_krazy Registered User Join Date: Jul 2005 Location: Seattle, WA Posts: 137	you could try rotating your rear tires to the front for diagnostic purposes to see if that changes.

04-04-2006, 11:19 PM	#19 (permalink)
Elvota Contributing Member Join Date: Jun 2005 Location: Phx, AZ Posts: 3,442	If you find a tire size difference... just drop the air pressure in the larger diameter set. Presto, instantly smaller diameter. Might help you troubleshoot at least. __________________ ================ 1990 4Runner \| V6 3.4 \| 5spd \| 240 someoddthousand miles \| SR5 \| SAS \| RLS \| 35's \| ARB \| TJM \| 217 to 1 \| W8000 - four wheels \| three sticks \| two hands \| one trail - RIGITY DIGITY visit the sticki chronicles

04-05-2006, 12:17 AM	#20 (permalink)
Bobakazi Registered User Join Date: Jan 2006 Location: Portland, OR Posts: 379	I'm not preaching, just blabbing. The Truetrac is a LSD, not a lunchbox or spool. I can't imagine it would make you vibrate that much with only 1/2" tire difference. I do try and keep my tires rotated, but I know I have had that much of a difference in the past and had no issues. I suppose if you had access to 4 more rims and tires that could be easily swapped for a hot minute, and see if it still occurs, that is what I would do. Or, you could just disconnect your rear drive and drive for a bit in 4wd. (essentially front wheel drive only) Any comment on my last post? __________________ '90 Extra cab V6 4x4 PU 5.29 gears. Detroit locker front, Detroit Truetrac rear. 35" BFG mudders. Trailmaster 4" susp, 3" body lifts. Add-a-leaf. K+N intake, 2.5" exhaust with Flowmaster 40 and a cat I got off an Evo VIII.

04-05-2006, 02:06 AM	#21 (permalink)
wrenchmonster Contributing Member Join Date: Jan 2005 Location: WA State Posts: 660	Rotating your tires will not make a difference because you are trying to determine if the varience between the front and rear is the problem. You're not changing anything in the equation. A+B=C or B+A=C ... it makes no difference. Deflating the tires will also make no significant difference. This is not a rubber balloon we're talking about, it's a tire. Deflating/Inflating will only change the level of the vehicle and the contact pattern with the ground. A 1/2 inch difference seems small but is deceptively large. You can't think of it like a piece of lumber. If you were to use the string method I decribed above you'd be surprised how much difference a 1/2 inch makes when you compare the two. The two pieces of string will not be different by 1/2 and inch, but maybe more like 1 1/2 inches. I'm no good at math at all, but maybe some of the math gurus will chime in. Disconnecting the rear drive line will probably work, I just think the tire change is more conclusive since you will maintain load on both axles. Beyond the string method, you could also get a piece of chalk and mark the tires 90 degrees to the ground. Then drive in a straight line for a while, get out and see where the chalk lines are front to rear. Last edited by wrenchmonster; 04-05-2006 at 02:09 AM.

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