Re: Re: Re: Re: Re: Lube directly on spline?
Thai said:
Just to clarify my point earlier and to eliminate any confusion for other members:
Lexus latest TSB is a definitive fix from what i have read. In the past, Lexus has tried several TSBs, including replacing driveshaft, which indicates to me that it is more than simply a greasing problem if Lexus went to this extent. None of the previous fixes were permanent. (I have a close friend who has this very issue with his GX). Only on the last TSB has the fix been permanent and definitive.
As stated many pages ago by me, this clunk is indeed a DESIGN problem of the rear suspension, not just the driveshaft. The LX470 does not have it. Sequoia does not (from what i understand). Only the GX and 4runner have this annoying issue. I do NOT think that it's a bushing or driveshaft or both problems.
It is very fortunate that it does no harm to the vehicle (as far as i can tell), but if you want to get rid of the problem, then you gotta do more than simply lubing the driveshaft or even replacing it with another factory one.
And as stated above, it's NOT a "wearing in" thing where this problem goes away down the road. It does not go away permanently without doing the full Lexus TSB (latest one). There is no way around it if you want to fix it permanently.
I have done some research on this issue on several of the Lexus forums, and from what I have read the initial attempts by Lexus to fix this issue were to replace the drive shaft using the same design/part # as was originally on the vehicle. It wasn't until later on that they came out with a re-designed drive shaft to replace the OEM one. From what I have read, the re-designed shaft has the slip joint splines coated with a teflon finish to aid in slip movement. This re-design goes directly to the heart of the lubrication issue we have been discussing.
"As stated many pages ago by me, this clunk is indeed a DESIGN problem of the rear suspension, not just the driveshaft. The LX470 does not have it. Sequoia does not (from what i understand). Only the GX and 4runner have this annoying issue. I do NOT think that it's a bushing or driveshaft or both problems. "
I agree one hundred percent, it is a DESIGN problem, but I firmly believe the issue is with BOTH the design of the drive shaft slip-joint, and the connecting bushings on the upper and lower control arms. Other than some adjustments for vehicles with the ride height control system, the ONLY components replaced when performing the TSB are the driveshaft and the upper and lower control arms. I don't have any first hand knowledge of the actual difference between the original and replacement parts, other than what I have read in the posts. But, those that took the time to check the replacement parts out, indicated that the control arms appeared to be somewhat heavier in design. Given the purpose of the control arms (to maintain the position of the rear axle in relation to the vehicle), it stands to reason that the major difference has to be in the bushings used to connect the control arms to the rear axle and frame. I strongly suspect that the original bushings are too soft, and they are allowing too much movement in the axle under braking. The only component that Lexus could have changed that would have had any effect on this movement would have been a stiffer bushing in the control arms.
"Lexus has tried several TSBs, including replacing driveshaft, which indicates to me that it is more than simply a greasing problem if Lexus went to this extent. None of the previous fixes were permanent. (I have a close friend who has this very issue with his GX). Only on the last TSB has the fix been permanent and definitive. "
"As stated many pages ago by me, this clunk is indeed a DESIGN problem of the rear suspension, not just the driveshaft. The LX470 does not have it. Sequoia does not (from what i understand). Only the GX and 4runner have this annoying issue. I do NOT think that it's a bushing or driveshaft or both problems."
"It is very fortunate that it does no harm to the vehicle (as far as i can tell), but if you want to get rid of the problem, then you gotta do more than simply lubing the driveshaft or even replacing it with another factory one."
"And as stated above, it's NOT a "wearing in" thing where this problem goes away down the road. It does not go away permanently without doing the full Lexus TSB (latest one). There is no way around it if you want to fix it permanently."
I agree that completing the Lexus TSB does appear to correct the problem with the GXs. But, the reason that this problem does not "go away down the road", is because the splines on the slip yoke don't wear down that easily, they are hardened metal. If they were to 'wear' down and the contact friction between them were eliminated the 'clunk' would go away because the slip joint would return to its normal position without any resistance. The rear axle would still be over rotating as before, you just wouldn't notice it because the clunk wasn't there.
All this being said, I suspect that Toyota isn't going to easily agree to apply the Lexus fix to the 4Runner. I suspect the total number of GXs they have to fix is vastly less that the # of 4Runners with this issue. I hate to say it, but the Lexus owners paid a premium for the nameplate, and Lexus is trying to keep them happy. I'm not sure Toyota will be wiling to spend the amount required to keep us 4Runner owners happy too.
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Sorry, i had to comment.
