edit: in hindsight, i probably shouldve put this in the drivetrain section.

after having an lnf tob bearing fail yesterday after less than 9 months and 10 k miles, i thought i would take apart my junk lnf and lsj throw out bearings to compare the two. i have heard of lots of people having trouble with lnf bearings, and now im one of them. ive had 2 lsj tob last for more than 70 k hard driven miles each. the first did not even fail. the clutch just wore out.

anyways, i took pictures of the noticeable differences between the two styles. maybe someone with more knowledge between the two can chime in, but i have read that the lnf is a better design because it does not bleed off pressure. i really do not understand how that is a good thing, but hopefully someone will elaborate.

these are the three main differences i noticed. from left to right in the picture below (lsj top, lnf bottom), the lower seal for the cylindrical rod, the top retaining clip, and the ball bearings. i think its a radial thrust design. correct me if i am wrong. the lsj seal has a larger diameter than the lnf and actually provided much more resistance to when i knocked off the rod. the smaller diameter sealed rod was easier to pull apart from the cylinder body. the retaining clip design is different, and i would think the square design wouldnt hold up as well as the tabbed design, but i could be wrong. and last, the bearings.. the lnf had 22 smaller diameter *****, and the lsj had 17 larger diameter ones. not sure the exact diameter, but i can mic it later in the week if need be.



on the next two pictures, you can see the difference in seal diameters. they were both stuffed into the cylinder (lsj left, lnf right)


(lnf left, lsj right)



i posted this because i want answers. not sure if anyone has done this before, but i wanted to see the difference for myself. any insight is appreciated

 

Keep your foot off the clutch unless you are pushing it in or letting it out. A foot resting on it eats the throw out.

 

^^^ this. The LNF has more travel that should measure. LSJ has a dust boot. The manufacturer has had issues. 99% of issues are faulty install. Looks like the retaining boots are damaged on one TB. Try using an impact driver on the bolt , and a little heat to soften the loctite next time. Good luck.

 

i dont rest my foot on the clutch. i only use it when shifting. as stated, ive put 70 k on 2 different tobs. neither of these are the ones that failed on my car currently. the lsj one here lasted 70 k. the lnf one f'ed up on install due to what was suspected to be too much material taken off of the flywheel from resurfacing multiple times. ended up getting a new flywheel and lnf tob and the tob failed less than 10 k miles later. ill have the transmission dropped soon and replace the one that failed on the car.

based on what i saw, i went ahead and bought a new lsj tob. i have heard that the lnf has more travel, but ive had much more luck with lsj tobs. luckily this time ill be installing myself, so if i mess it up, at least ill learn from it

 

I'll keep that in mind for the install. It'll be my first time dropping the trans, so I hope it'll go smoothly. Thanks

 

I would disagree just for the fact that 99% of the redline/balt owners are not complete dumb asses

 

I can't figure out what you just said. I'd 99% are dumbasses.

 

I'll back John here..... Most of the fault tobs are installer error. I 've done at least 15 that were faulty throw out bearings and all ended up installer error. One guy even did his 3 times with 2 oem and 1 aftermarket tob and all 3 failed.

 

are there any installation errors that you all can remember specifically?

 

trying to "bench bleed" like really.
hanging the TOB on the shaft and tightening the bolts to pull it in to position
hanging the trans on the input shaft while installing
forcing the trans into place when the clutch disc is misaligned, using the trans bolts to draw it down
not torquing the TOB bolts
not using a new clutch pipe
not tightening the clutch pipe correctly cross threading the pipe nut
not using vdub sleeve lube or similar on the TOB sleeve
not aligning the clutch disc properly with correct tool
not centering pressure plate on dowels ( hard to do with GMPP sachs cover the dowel holes are larger than the dowels
not using a torque wrench on all fasteners
leaving out the trans spacer
screwing up the distribution block
not sealing the master cylinder line when removing the distribution block if you do it that way (I dont)
etc

 

ok so what you are saying is 99% of the balt/redline owners are complete dumbasses and that would be including yourself and that leaves only gm techs capeable of doing the work **** pat yourself on the back for being in the 99% omiotek mr powell even me and all the rest

 

Here is what I know: mostly the forums and facebook we learn of the DIY install issues. Thats probably 10% of the parts consumed in North America for these cars I am guessing.

Most of the time, folks dont have trouble and there are not a crap ton of posts saying "whoo hoo I installed my clutch and it works great!!!"

We have installed like 500 here since 2004 and had ONE BAD TOB. ONE.

 

I replaced my clutch last night and not it wont go into gear at all. I bled the clutch a few times and it never changed still felt spongy. I bought a stock luk clutch any one know why this would be going on? Its an 07 lsj
R Throwout bearing?
Yesterday at 12:53am ˇ Like

C Thats what ive gathered
Yesterday at 1:51am ˇ Like

JA LUK clutch is self adjusting. If u did not preset the SAC fingers that happens Put the cover in a press and set the SAC fingers then reinstall
Yesterday at 8:10am ˇ Like

R ^^^The master has spoken!
Yesterday at 9:53am ˇ Like

L as i said on the other post....throw out bearing...you didnt replace an old worn tob and now its gonna bite you in the ass. sucks ass....i had a defective tob from gm and it bite me in the ass hard....lasted about a month and than BANG no tob and a toasted clutch from trying to get her home.
Yesterday at 1:00pm ˇ Like

C I didnt install the clutch properly and i changed to a new throw out bearing
1 hr ˇ Like ˇ 1

Kyle Boszak Did you put the disc in backwards? Lol.
1 hr ˇ Like

C No i put it on the wrong alignment holes

 

Thanks everybody.

 

no one here is saying that 99% of cobalt owners are retards man. what we are saying is that 99% of the failed throw out bearing are due to installer error. Every clutch job that's showed up at the shop on a flat bed because the throw out bearing took a crap I have found to be installer related and even after I show the customer they realize where they went wrong. I know of 1 person that installed the tob right and had it fail. I had one customer do it 3 times with 3 different throw out bearings. 2 oem and 1 aftermarket only to have all 3 fail. Not saying that someone cant DIY because people can but too many people get the job done partially and in the end do something wrong when maiting the transmission or installing the tob. truth be told.

 

someone did

 

No, he said 99% of failures are install error, not 99% of people install them wrong. There's a big difference.

Lots of people install them without issue. They're simply saying IF it fails, it's usually install error.

 

You nailed it. I have a big long rant is another thread somewhere reguarding the topic too.

 

True, but to me that's not exactly something worth celebrating over. Jap installed my 4.45 trans and new gmpp clutch kit in his garage and has been working fine and while I appreciate that everything went smoothly, it's not something I feel I have to share because it's just a clutch. Ofcourse you're going to hear about the failures and problems, but you're not going to hear about all of the clutch installs that were successful IMO.

 

I don't understand why there are so many people with TOB/clutch install problems. It is such a simple job. Unbolt old TOB, check new TOB for signs of overextension, reinstall on trans, tighten bolts evenly to ensure it seats properly and not cocked, torque to 89in lbs.

 

I have to agree that it's mostly install error and wonder what people are doing wrong.

I've personally done 4 LSJ upgraded clutch jobs on my own and friends car and all worked great, no issues. We just follow the recommended procedures and trq it all to specs.