Lexus IS Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter #1
My question is that do any of you hear a thump when you cange gears on the 5 Speed. I have had this noice for a while now but I think its time to findout what the hell is going on. After all its under warrenty.

Any thoughts people.???
 

·
Registered
Joined
·
518 Posts
Hey buddy. Its a common question. The thump you hear when switching gears is normal. Its (believed to be) due to slack in the drivetrain that is supposed to be there. Dont sweat it
 

·
Moderator
Joined
·
8,880 Posts
A quote from another thread.

RxVedub said:
...BTW the thump is not just a tranny issue, more of a combination of chassis design and sincros in the trany. The sincrose grab the gears so fast and hard that it sends a shock wake thrue the drive shaft and the dif. The dif mounts absorb the shock, but the chassis design projects a "thump" noise when this occurs. There is no fix it on this problem only chassis redesign.

No bull sh*t, strait from my Lexus class at the western regional office.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #5
Thankx for the feedback guys. And I was wondering if there is anything that could be done to fix it...If not its cool.

thankx again
 

·
Nygmatic
Joined
·
2,683 Posts
when you shift, dont cram the lever into place. let the lever be "sucked in". its kinda hard to tell the difference at first, but once you get the hang of it, it will be a night/day difference. you will not hear the thump sound and your shifts will be much smoother.

for starters you could try the "eggshell" technique. not my naming.. i heard it from someone else :) when shifting, instead of grabbing the lever, just use your fingers to place the lever into place. do not push hard either. using this techinque will be difficult if you arent placing your clutch correct and/or you arent at the right rpm. but just practice and the thump will go away or be nominal.
 

·
Registered
Joined
·
4,968 Posts
You can barely hear it if you have the radio on. I went for a long time without hearing it. One day after it was in service, i heard it. Because I got in the car and they had turned the radio off.
 

·
Registered
Joined
·
46 Posts
Rev match your shifts and the thump is non-existent.[/quote]

This rev matching suggestion has never made much sense to me, because my car makes the noise when shifting at a dead stop into first gear. What kind of rev matching are you supposed to do if you are sitting still at a red light in neutral, then shift into first gear and you hear the thump? Not that it really matters to me because the thump doesn't bother me, but just my $.02
 

·
Registered
Joined
·
5,941 Posts
nycggp said:
This rev matching suggestion has never made much sense to me, because my car makes the noise when shifting at a dead stop into first gear. What kind of rev matching are you supposed to do if you are sitting still at a red light in neutral, then shift into first gear and you hear the thump? Not that it really matters to me because the thump doesn't bother me, but just my $.02
Obviously you can't rev match from neutral to 1st but if you rev match on your upshifts from lets say 1st to 2nd then 2nd to 3rd, the shifts will be so smooth that it will feel like you're driving an automatic. You'll also notice the thump doesn't even occur.
 

·
Registered
Joined
·
831 Posts
i can't figure out how to rev match while upshifting. I got downshifting down pretty cold though :)
 

·
Moderator
Joined
·
8,880 Posts
flproject13 said:
i can't figure out how to rev match while upshifting. I got downshifting down pretty cold though :)
You move the pedal the opposite way of if you were downshifting. :wink:
 

·
Nygmatic
Joined
·
2,683 Posts
if you are hearing the thump from neutral to one in a deadstop situation, make sure you have the pedal fully depressed. in addition make sure there isnt anything underneath the pedal (carpet/mat/etc) that is preventing you from depressing the clutch all the way.

ive learned with this car that my right foot has to be a little lazy between shifts. meaning that i dont let go of the gas as fast as i am moving my left foot. kinda awkward, but it gets a little getting used to.
 

·
Registered
Joined
·
4,968 Posts
I got the ultimate solution to this thump noise...
put on some Planet Rock and shift to the beat.
bump.......bump...bump..bump.bump.... bump...
 

·
Registered
Joined
·
15,585 Posts
I love the thump....

reminds me that im driving a manual...

Going from 5th down to 4th creates a nice thump...

I guess its personal preference, but I have grown to love it
 

·
Registered
Joined
·
46 Posts
HoustonLex said:
I love the thump....

reminds me that im driving a manual...

Going from 5th down to 4th creates a nice thump...

I guess its personal preference, but I have grown to love it
Yeah, I agree, there's something about that thump that I like. I've been driving an automatic IS300 for the last two weeks because my car is in the shop, and its just not the same, not nearly as fun for me! And I miss the thump! :wink:
 
1 - 17 of 17 Posts
Top