I have a 2000 LX with 185,000 miles. My clunk occurs between the 1-2 shift. My shift from 1st to 2nd is perfect and then within a 1/2 second comes a clunk. The clunk is worse with throttle pressure...i.e. If I'm going uphill with more throttle pressure, the clunk is worse. If I'm pointed downhill, I can ease the 1-2 shift with no clunk. The transmission fluid is real clean and the tranny works perfectly otherwise. If I shift it manually from 1-2...no clunk. Lexus techs say they put it in 2nd which I guess allows it to shift 1-2 only....no clunk. lexus techs say its a tranny failure and needs to be replaced. My wife says shes driving it untill she blows!! My question is this.....am I missing something? Any ideas? Does anybody think this is the dreaded driveshaft clunk? Lock-up converter?? Suspension?? Thanks for giving it some thought!! Alan
My "dreaded" clunk may be a bit different..
- Thread starter sequimbound
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I reckon it is the sound of the torque converter locking-up under load.
(The torque converter allows some slippage at low speed so that you can stop the truck in gear without stalling the engine. Then it 'locks' at higher speeds for better energy transfer: - it's doing what its supposed to do, it's just not supposed to make noise)
The symptoms you describe could be caused by low transmission fluid level, or by using the wrong fluid.
First, I would check the fluid level- with the engine running, truck parked on a level surface, warm transmission. -Make sure the fluid is filled to near the top of the range.
If that doesn't fix it, then I would exchange all of the fluid with the proper spec fluid.
If that doesn't fix it, then I'd have it checked out by somebody who knows automatic transmissions- it could be a stuck valve or something easily repairable without replacing the whole tranny.
If it was me, I would avoid the Lexus dealer, those technicians are not allowed to fix your transmission, their only option is to replace the whole unit.
The symptoms you describe do not seem consistent with what other people have reported prior to transmission failure. I bet your problem is something that a competent transmission shop can easily fix. - avoid the dealership here.
Hope this helps.
(The torque converter allows some slippage at low speed so that you can stop the truck in gear without stalling the engine. Then it 'locks' at higher speeds for better energy transfer: - it's doing what its supposed to do, it's just not supposed to make noise)
The symptoms you describe could be caused by low transmission fluid level, or by using the wrong fluid.
First, I would check the fluid level- with the engine running, truck parked on a level surface, warm transmission. -Make sure the fluid is filled to near the top of the range.
If that doesn't fix it, then I would exchange all of the fluid with the proper spec fluid.
If that doesn't fix it, then I'd have it checked out by somebody who knows automatic transmissions- it could be a stuck valve or something easily repairable without replacing the whole tranny.
If it was me, I would avoid the Lexus dealer, those technicians are not allowed to fix your transmission, their only option is to replace the whole unit.
The symptoms you describe do not seem consistent with what other people have reported prior to transmission failure. I bet your problem is something that a competent transmission shop can easily fix. - avoid the dealership here.
Hope this helps.
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Thanks so much! My first thought was a converter. I'll check the fluid levels...the last fluid change was done at lexus....I just assumed they would use the proper fluid. Now I need to find a reputable trans shop in the South Bay (los Angeles)
Thanks again for your input!!
Thanks again for your input!!
I could be wrong about the torque converter.
Other folks will know more about it.
But those are the things that I would check first before shelling out for a new transmission.
If you have access to a shop and don't mind getting dirty, it might be worthwhile to drop the pan on the bottom of the transmission and see if you find any metal parts in there. Metal in the pan would be a bad sign, but based on your description, I bet the problem can be fixed without replacing the whole tranny.
Other folks will know more about it.
But those are the things that I would check first before shelling out for a new transmission.
If you have access to a shop and don't mind getting dirty, it might be worthwhile to drop the pan on the bottom of the transmission and see if you find any metal parts in there. Metal in the pan would be a bad sign, but based on your description, I bet the problem can be fixed without replacing the whole tranny.
Are you positive both propeller-shafts slip joint splines, all spider joint, both CV and both axle snap rings are good. Sometimes a hard-shift can cause just a little back lash throughout drive train. Personally I don't care for the dealers ATF. I prefer full synthetic with its higher viscosity, for a smoother shift.
I recently had a problem with my transmission although my problem was a bit more pronounced than yours.
It began with the CEL and VSC OFF light illuminating after I started the car one evening. I decided to drive the vehicle to try and diagnose what the issue really was as I was confused as to its cause [I had literally just started the vehicle].
What I experienced was that engine power was severely limited under normal+light acceleration [LIMP HOME MODE] while the shifter was in the 'D' position however once I tried shifting manually, she acted more normally although there was still some very apparent clunking and jerking going on.
I pulled the error code and looked it up and found that the fault lay with one or more of the hydraulic pressure solenoid valves in the transmission valve body that oversees normal automatic shifting.
We found an American based company located here in Dubai and changed all the solenoid valves at one go [just to be on the safe side and since the tranny was out].
We also took the opportunity to install a separate trans-oil cooler [highly recommended here in the GCC] and so far the problem has not returned...yet.
I do realize that mine is more of a worse-case scenario and also that you haven't mentioned anything about your CEL light coming on or your vehicle going into LIMP HOME MODE - but I hope it helps anyway.
Yovan Noel.
Posted via IH8MUD app
It began with the CEL and VSC OFF light illuminating after I started the car one evening. I decided to drive the vehicle to try and diagnose what the issue really was as I was confused as to its cause [I had literally just started the vehicle].
What I experienced was that engine power was severely limited under normal+light acceleration [LIMP HOME MODE] while the shifter was in the 'D' position however once I tried shifting manually, she acted more normally although there was still some very apparent clunking and jerking going on.
I pulled the error code and looked it up and found that the fault lay with one or more of the hydraulic pressure solenoid valves in the transmission valve body that oversees normal automatic shifting.
We found an American based company located here in Dubai and changed all the solenoid valves at one go [just to be on the safe side and since the tranny was out].
We also took the opportunity to install a separate trans-oil cooler [highly recommended here in the GCC] and so far the problem has not returned...yet.
I do realize that mine is more of a worse-case scenario and also that you haven't mentioned anything about your CEL light coming on or your vehicle going into LIMP HOME MODE - but I hope it helps anyway.
Yovan Noel.
Posted via IH8MUD app