Serious vibration - diff drop needed?

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GaFJC

GaFJC

10 Year 15 Year
Joined
Jan 17, 2009
Threads
21
Messages
553
Location
Southern Mountains
Last Friday I discovered I have a new and often serious vibration. Saturday Feb 11th had my Ironman bumper installed and t bars on adjusted to almost level out the front end. This past Friday heading up to the North GA Mountains I noticed that I had a serious but infrequent vibration. It ONLY happens under hard acceleration going up a steep grade and generally once the transmission has kicked down not just once but twice. Speed isn’t so much of a factor as is grade and RPMs but it’s generally north of 55 mph and most likely 60 to 70 mph. Generally on a steep uphill stretch of road and RPMs between 2500 and 3000. The 100 was loaded down with ¾ tank of gas and kids, gear and dog.

I CANNOT duplicate the vibration under the following conditions:

• Very hard acceleration to 65 mph + from a dead stop on level ground.
• Very hard acceleration to 80 mph + from speeds of 40 to 45 mph on flat roads or small hills.
• Steep road grade acceleration without load (kids, gear and dog)
• Normal acceleration on highway on-ramps or at cruising speeds of 70 mph +.

My only guess is with the torsion bar adjustment (and bumper weight), the road grade/incline and payload contribute to the perfect storm to cause the vibration. Maybe it shifts enough of the vehicle weight to the rear to relieve weight on the front.

It didn’t do this before the bumper install and tbar adjustment.

Any suggestions? Are the tbars maxed out and need to be adjusted slightly lower?

Would a diff drop kit help? I realize those are typically used with suspension lifts like OME (I have no suspension lift) or other aftermarket kits.

Thanks in advance for your help.
 
Sounds like either UJs or spindle bearings.
Guessing the latter. When did you check/pack them last?
 
petrotk40 said:
how much rake do you have? The front end should be about 1" lower than the rear
Click to expand...

Good question. I need to measure it because it's that close and hard to tell by just looking at it. It may be 1" lower but will have to get the tape out.
 
uHu said:
Sounds like either UJs or spindle bearings.
Guessing the latter. When did you check/pack them last?
Click to expand...

I believe the spindle bearings were done in December when I had my front PowerStop rotors and pads installed. I specifically asked the mech to do them. I guess there's always the chance he didn't.
 
Last edited:
GaFJC said:
I believe the spindle bearings were done in December when I had my front PowerStop rotors and pads installed. I specifically asked the mech to do them. I guess there's always the chance he didn't.
Click to expand...
My experience with t0yota mech's is that most of them couldn't even identify the spindle bearing. It is probably different on your side of the puddle, with more trucks with a similar set-up.
 
GaFJC said:
I believe the spindle bearings were done in December when I had my front PowerStop rotors and pads installed. I specifically asked the mech to do them. I guess there's always the chance he didn't.
Click to expand...

The spindle bushing/bearing uhu is referring to is not the same as wheel bearing (commonly done with rotors) and most mech don't know about them or how to service them. Click the link below and take a look at post #10 on a one :banana: way to inspect the condition and lubricate them while you are there.

https://forum.ih8mud.com/100-series-cruisers/448945-how-lubricate-front-axle-shaft-bushings.html
 
LandCruiserPhil said:
The spindle bushing/bearing uhu is referring to is not the same as wheel bearing (commonly done with rotors) and most mech don't know about them or how to service them. Click the link below and take a look at post #10 on a one :banana: way to inspect the condition and lubricate them while you are there.

https://forum.ih8mud.com/100-series-cruisers/448945-how-lubricate-front-axle-shaft-bushings.html
Click to expand...

I'm an attentive MUD student: I asked my mech to service both the wheel bearings (MUD advice) and spindle bearings (Slee advice when purchasing the brake kit). But just because I asked (twice) doesn't mean either were completed.

It sounds as if most folks here think it is one or both of these and not necessarily directly steering or suspension "geometry"?
 
GaFJC said:
I'm an attentive MUD student: I asked my mech to service both the wheel bearings (MUD advice) and spindle bearings (Slee advice when purchasing the brake kit). But just because I asked (twice) doesn't mean either were completed.

It sounds as if most folks here think it is one or both of these and not necessarily directly steering or suspension "geometry"?
Click to expand...

I agree

FWIW - I have had 2 lifted 100 with no diff drop and never experience any vibs.
 
Make sure you have enough droop, 2" and that the rake is there. I reindexed after installing my bumper with winch and now I have a muffled clunk that I cant find. Im about to order sway bar bushings and shocks. Also, make sure that your drive shafts are well greased.
 
Also, lift the front of your truck up and grab each wheel and see if they are solid or if there is movement at 12 & 6 or 3 & 9. I had a vibration and the front passenger wheel was loose and it turns out the bearings had no preload on them.
 
Gottagetone said:
Also, make sure that your drive shafts are well greased.
Click to expand...

I have one zerk on the front drive shift that is almost impossible to get to and may be dry.

Gottagetone said:
Also, lift the front of your truck up and grab each wheel and see if they are solid or if there is movement at 12 & 6 or 3 & 9. I had a vibration and the front passenger wheel was loose and it turns out the bearings had no preload on them.
Click to expand...

Will do this and use LandCruiserPhil method of spindle bearing/bushing lube this weekend. Will also take it in to have the tires R & B event though they aren't due yet.
 
Working down the list of possible culprits, this week I've done the following:

Had the u joints checked and they're ok, tires rotated and balanced (along with alignment - wheel bearings checked for play at that time). I also verified with the mech (a former Toyota tech) that did the CVs (August) and the PowerStop rotors and pads (Dec) if they did the wheel bearings and spindle bearings/bushings and the answer was yes.

Still have the vibration and its become more common although subtle starting at speeds of 50 + mph to roughly 60/65 mph and regardless of grade/terrain.

Remaining on the to do list: Perform LandCruiserPhil spindle bearing/bushing lube just as much for a visual inspection for lube as to lube them.

I still can't but wonder if I have a bad tire.
 
I'm not saying this is your issue but, as a side note, I chased a cyclic vibration for years in the front end of my, now retired, Ford van. I tried everything - different tires, different wheels, new bearings, nothing helped. Finally it was time to replace a rotor and low and behold....smooth as glass....no more vibration. I never would have guessed a rotor had gone out of balance.
I hope you get it solved. I feel your frustration.
cp
 
badlander said:
I'm not saying this is your issue but, as a side note, I chased a cyclic vibration for years in the front end of my, now retired, Ford van. I tried everything - different tires, different wheels, new bearings, nothing helped. Finally it was time to replace a rotor and low and behold....smooth as glass....no more vibration. I never would have guessed a rotor had gone out of balance.
I hope you get it solved. I feel your frustration.
cp
Click to expand...

Good to know. In this case I believe my rotors are fine as they were installed 2 mos before the bumper and took a 600 mile + road trip a week or so after without problems.
 
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