Rig Shaking but ONLY at 30mph??? (1 Viewer)

[willmtaylor]

I’ve noticed that my ‘05 shakes or shudders (the body—not like engine struggling) ONLY at 28-30mph and ONLY sometimes. It feels like I’m going over the interstate shoulder bumps. I suspect it’s when I get up to 30mph in 3rd? Does this sound right?

Otherwise, the rig handles and drives great, but I can’t figure out the shaking at 30.

I’m a noob trying to learn more and only been an LC100 owner for a week, so be kind and talk to me like I’m an idiot (bc I pretty much am).
TIA,
Will

 

[brettk]

Sounds kind of like a control arm bushing, maybe an alignment issue. Can you give us some more information? Any modifications or work the previous owner did, like a lift, would help.

 

[willmtaylor]

Sounds kind of like a control arm bushing, maybe an alignment issue. Can you give us some more information? Any modifications or work the previous owner did, like a lift, would help.

Bone stock. MS 255/70R18 tires on there.

I’m taking care of a lot of deferred maintenance at the moment (already replaced front brakes & bearings, and struts all around).

But like I said, zero mods and all fluids are within range.

 

[Malleus]

Every system has a series of vibration frequencies that are significant in that they cause the entire system to vibrate with a lot of energy. The first, and largest, is usually the only one anyone tries to dampen out. Your engine has one; it's the redline on the tach.

Typically, when the whole vehicle vibrates with a lot of energy, it's related to the rolling components, unless it's only observed on one specific road surface, for instance, you observe vibration only on one stretch of road and nowhere else. If, on the other hand, it's speed dependent, the root cause list gets a lot larger.

At any rate, the wheels are always in the root cause list and are the easiest to check. Look for missing wheel weights, unless you've had new tires installed recently AND observed the vibration ONLY after the tires were installed. Then you should go back to the installer and make him prove the wheels are balanced.

If the wheels are OK, then start looking into the suspension components. Also, keep an eye on the tach when you observe the vibration and make a note of the engine rpm. You're looking for how much, if any, deviation in rpm during the observed vibration incidents. If there is none, the engine is also in the list. If there is a lot of variation in rpm, it can't be the engine, so you can cross motor mounts off the list.

HTH

 

[Tanner H]

Did the shuddering happen right after your wheel bearings were serviced? if so, could be bearings were not preloaded correctly and have play.

 

[Africaster]

Check for sand/mud caked on the inside of your rims … even a little causes significant wobble (think how small the weights are that are used to balance tyres). Good luck

 

[willmtaylor]

@Malleus @Tanner H @Africaster Thanks!

Just had bearings & brakes done, and it’s doing it same before and after.

Also, if it helps diagnose, it DOESN’T always shake at 30mph:

• It only sometimes when I’m accelerating and I THINK in 3rd gear.
• Sometimes, if I hit 30mph at a different gear, it won’t shake.
• When I slow down from going faster, it never shakes.

 

[LC CT]

Things I’ve had issues with in the past is a 4Runner that would shudder at low speeds slightly uphill giving a little gas around 30 mph, it was a torque converter issue. Felt like the whole truck shook. I believe they share the same or similar tranny as the 100? This was kinda fixed by doing tranny fluid through the cooler lines and then adding “dr tranny shudder fix” sounds corney but works really well. Still have the truck, shudder is minimal but still there at times
Other time I had a crazy shudder was a Tacoma’s Ujoint being bad. But it was more when you’d let off the gas and drop into 30mph range whole truck would shake. Did it on the accelerate too but much more pronounced on the deceleration

 

[Tommy Callahan]

I had this EXACT same problem on my '04 with about 204K mi. My mechanic put in a tans fluid additive (unfortunately I don't know what) and it solved the issue completely. When I was talking about it with him he said his go-to transmission guy said it was known issue and suggested the additive. Hope this helps!

 

[LC CT]

was

I had this EXACT same problem on my '04 with about 204K mi. My mechanic put in a tans fluid additive (unfortunately I don't know what) and it solved the issue completely. When I was talking about it with him he said his go-to transmission guy said it was known issue and suggested the additive. Hope this helps!

Sounds like doctor tranny, it sounds like a gimmick but worked on my 4Runner. The torque converts are known to develop a shudder. Feels just like the rumble strips on the highway. Would be a good idea to put some clean fluid in and add dr tranny.

 

[LonghornLX]

I had shuddering issues due to a torque converter problems on my 2003 LX470.

Mine was in the range of 30 -45 MPG and up or downshifting during the shudder would stop the situation.

It did not occur every time. It did NOT show up in any faults that a Transmission shop could detect.

I hope this isn't your situation as the only resolution was a transmission replacement along with a new torque converter. I was fortunate to have bought a warranty that took care of the cost at the time ( 12 years old with 40k miles still qualified for warrant )


Things that helped me temporarily :

1. Enable the PWR button keeping the revs slightly higher per gear minimized the event
2. This helped temporarily stop the shuddering : Shudder Stop

 

[t140frank]

Have your passenger poke their head out the window when it starts shaking and see if the front wheels are shuddering ( death wobble).
If that's the source of the problem you might have play in the bearings, flat spots on tires, tire alignment off, suspension bushings worn out, or something bent up front in the suspension.

 

[willmtaylor]

Ok, so stupid follow-up question: If I were to try some Lucas Transmission Fix (LUC10009), where would I pour that in?

 

[LonghornLX]

Some lc100s have a transmission dip sticks. If you do just pour it in through there if not there is a fill plug driver side on the tranny