Mechanics

SHUDDER

2000 Lexus LS 400

Shakes or Wobbles problem
2000 Lexus LS 400 V8 Two Wheel Drive Automatic 103567 miles

Thanks my lexus has a shudder from about 35 to 43 mph, I am a ase cert tech with 10 years gm exp and 20 yrs honda exp. I have done all basics, tires, wheels, mounts. This car is killing me, engine on or off it shudders when you enter the 34 to 43 mph range on accel as well as coast down. It is dead smooth above or below this speed. I installed another drive shaft - no improvement, conditions gets more pronounced as ambient temp goes down. I WILL DONATE MONEY IF YOU CAN HELP THANKS JIM
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Jim trebonsky
January 9, 2010.



Start here to find out if the tranny has a mechanicl problem or not.
MANUAL SHIFT TEST 1. With ignition off, disconnect transmission solenoid connector. See Fig. 6 . Road test vehicle and ensure transmission gear changes correspond with selector lever position. See GEAR APPLICATION table. 2. If abnormality exists, a mechanical transmission problem exists. Turn ignition off. Reconnect electrical connector. Clear trouble codes from ECM memory, as disconnecting electrical connector may set a trouble code. See CLEARING DIAGNOSTIC TROUBLE CODES under DIAGNOSIS & TESTING. NOTE: Perform manual shift test if no trouble codes exist. Manual shift test determines if problem area is in electrical circuits or a mechanical transmission problem.


http://www.2carpros.com/forum/automotive_pictures/62217_sol_con_1.jpg


http://www.2carpros.com/forum/automotive_pictures/62217_solinoid_1.jpg


Merlin2021
Jan 10, 2010.
Merlin thanks for the quick reply, this problem is a vibration or shudder you can feel in seat and floor. It is on accel, coast, cruise, in neutral, or any gear, even with engine not running

Tiny
Jim trebonsky
Jan 10, 2010.
Seems like it's when engine and tranny are in one to one ratio, possibly the torque converter or a forward clutch. Any codes present? Condition of the fluid?

Merlin2021
Jan 12, 2010.
There are no codes stored, the fluid is very good, I change regularly. It is much more noticeable when ambient temp is low. It does when the engine is shut off. Thanks JIM

Tiny
Jim trebonsky
Jan 12, 2010.
Try testing the shift solenoids, it can be done with an ohm meter, heres how:NO. 1, NO. 2, NO. 3 & NO. 4 SOLENOIDS 1. To check solenoid seals, remove suspect solenoid. Connect battery voltage to solenoid. Apply 71 psi (5 kg/cm 2 ) to solenoid with battery voltage connected. 2. With battery voltage applied, air should pass through solenoid. Disconnect voltage to solenoid. Ensure air does not pass through solenoid. Replace solenoid if defective. 3. Using ohmmeter, measure resistance between case and solenoid connector terminal. Resistance should be 11-15 ohms. Replace solenoid as necessary.


http://www.2carpros.com/forum/automotive_pictures/62217_sols_1.jpg


SLN, SLT & SLU SOLENOID Raise and support vehicle. Remove transmission oil pan. Remove appropriate solenoid. See Fig. 1 . To check solenoid operation, connect positive battery voltage to solenoid terminal No. 1. Ensure an 8-10-watt bulb is placed in-line of positive lead. See Fig. 12 . Connect negative lead to terminal No. 2 and monitor valve's movement. Replace as necessary.


http://www.2carpros.com/forum/automotive_pictures/62217_slu_1.jpg


Merlin2021
Jan 13, 2010.
MERLIN, DO YOU THINK THIS PROBLEM COULD BE CAUSED BY THE TRANSMISSION IF I SHUT THE CAR OFF AND IT STILL OCCURS. THANKS JIM

Tiny
Jim trebonsky
Jan 14, 2010.
Let me get it right, car is off, and your doing 35-40 mph, and it has a chatter, or vibration in the drivers seat area? Car is in drive? Tranny would still be spinning internally, and engine too. Backfire when you restart? Key if OFF position? On? I checked for PCM reflashing on this, no TSB released to Mitchell on demand, but it may be worth a trip to Lex dealer to check if they have any info. Many issues are solved with a reflash. Other than that when you removed the pan last time was there any friction material or steel in the bottom? Direct clutch is what I'm thinking.I work on mostly Ford, Lincoln, Merc, and new wires and plugs can even solve it on these cars, On LEX not sure, but any weakness in tune up parts can be exposed during this shift point. But with engine off, I doubt it's the tune up. What does it do if you shift to neutral?

Merlin2021
Jan 14, 2010.
This vehicle has a shudder, very simillar to a drive shaft out of balance, this is not a trans clutch shudder. It will do it with the engine shutoff. It is much worse whe the ambient temp is cold, its hardly noticable in summer when it is hot. I have driven cars with auto trans clutch shutter and this completely different the engine and trans on this car are as smooth as butter

Tiny
Jim trebonsky
Jan 14, 2010.
The only thing left then is mounts, but you did say yours were good? You know how this goes Jim, if I cant drive this, and there are no tech bullitens about it, It's guesswork.
The differential is a hypoid-type with integral carrier housing. The differential is mounted with rubber mounts in the rear suspension member. The drive shaft is a 2-piece design, supported by a center bearing. You have checked these mounts, and the center bearing? The center bearing is THE most common problem area on these and BMW. Why yours only does it in 3rd? But I have seen stranger!
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Merlin2021
Jan 15, 2010.
Jim did you ever figure out the problem? I'm having the exact same issues, its driving me crazy

Tiny
Samslam
Jun 2, 2012.
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