Almost 2 months ago i blew my transmission in my 06 ss/sc. I have the transmission out and a new one on the way, but it is time to possibly upgrade clutch/throwout bearing/flywheel.

The issue - after upgrading to zzp's pcm with a redline of 7200, I notice that above 6500 rmp my clutch seems to lose pressure and starts falling to the floor. I then try to disengage the clutch to shift into neutral after my WOT run and i only have half the pedel left and i cant properly disengage the clutch. I then have to pump the clutch a few times to return the pressure to the clutch and then i can disengage the clutch no problem.

What i ask of you - I would like to avoid buying anything if i don't have to, but would like to fix this issue as it may have caused excess stress on the transmission. What is the term for what is happening to my clutch at high RPM? What should i upgrade to fix it?



Transmission

F35 non-LSD 4.05


Clutch

AC Delco clutch replaced only a few months ago.


Flywheel

Factory OEM Stock


Throwout Bearing

Factory LSJ Throwout bearing, I believe this is my issue? ZZP says "The factory LSJ throwout bearing bleeds off pressure when you press in the clutch"


As far as HP/torque, i shouldn't have that much more than stock. only upgrades that result in more power are K&N AF, med Headers and Downpipe, and ZZP PCM Tune.

Thanks in advance, you guys rock!

 

have to ask the obvious, only because you did not specify, but how do you know you blew the trans? you only mention the loss of clutch pedal at wot. that would be a problem with the throw out bearing for sure.

people get on here and bash the lsj throw out bearing, but ive had 3 lsj throw out bearings and 1 lnf. The 2 of the lsj's lasted over 70 k miles. the lnf, less than 10. im back on an lsj throw out bearing now.

last I had read was that the lsj bearing has a pressure relief valve internally. I would think that this would actually help, because it would bleed off any excess pressure above the set point of the relief valve. it might require more bleeding over its life, but id take that over a tob that might overpressure (i.e. due to using a longer adjustable master cylinder rod like zzp sells) and wear out quicker.

 

I pulled the trans and inspected it is the short answer, but if you want to hear how it happened here it goes:
Pulled out of parking lot and car was jerky in 1st. put it in 2nd and then the knob was bouncing off the bottom of 2nd. i then thought it popped out of 2nd into neutral and thought it was bouncing off second gear. I then pushed in clutch and pulled down on second gear. The wheels locked up and then the momentum of the car finally overtook what ever tried to lock the wheels up. The car was in neutral and i rolled to the side of the road.
At this point i thought it was either my tranny or a wheel bearing so I tried putting the car into a gear and it locked me out and i finally got it into gear and tried to roll forward a bit. The wheels were locked up again and as i tried to move forward i smelled clutch. i tried pulling it out of gear and i was able to physically move the shift knob out of gear (and in other gears) but the car was still stuck in that gear. I then turned the car off and got it towed home.
I told my dad that my trans was blown and he said let me see for my self. he started it and reved it a few times and then a pin came through the bottom of the housing with trans fluid pouring all over the driveway.
I pulled the tranny and there was a 3" hole in the bell housing and a pin sized hole in the bottom of the case where trans fluid poured out.
I can post Pics later if needed.

 

Ah okay. To your original question though, youll want a new throw out bearing. Might as well get a new flywheel. One stipulation that gm makes for the lnf tob is that you have to use a new flywheel and not a resurfaced one. Ive heard of people resurfacing anyway though.

 

I had mine resurfaced, but alot of people advise against it because there really is not much you can take off. Better to just get a fresh one

 

Check your clutch pipe, distribution block, and the plastic clip in between. If theyre still in good shape and you want to reuse them, then go ahead.

Most will say to order a new clurch pipe with the tob which is fine, just make sure that the seal of the old pipe is out of the distribution block.

Crate engine depot has everything that youll need. Flywheels have recently gotten stupid expensive though. If you can source that elsewhere then cool. My last clutch was an exedy with flywheel combo for 325$ from carid.com. It looks just like the gmpp upgrade but cheaper when you factor in new flywheel costs

Careful with the tob bolts. Theyre torx bit and strip very easily.

 

Ok, so I'm going to try upgrading the TOB to the LNF and try and reuse the old clutch pipe. I will keep the newish clutch in and upgrade to a Fodenza flywheel from ZZP.
Can I reuse the bolts from the old flywheel?
Thanks guys!

 

I would just use the stock flywheel from ZZP. It's Chinese but will work. You have to order new flywheel bolts I would not reuse them. Crate engine depot has the best deal on them.

 

Thanks I'll check out the bolts

 

everybody went nuts and bought them all out because of the price hike for oem

 

The new bolts is not just a recommendation it's a necessity. They are torque to yield.

 

Yeah zzp is out of stock

 

It's a Luk


I reuse them flywheel bolts sometimes. Dab of blue loctite lol.

 

This is good to know. I will buy new bolts for sure.

 

Do you have an after market clutch? Sounds like a TOB spacer might be needed to keep the LNF TOB.
How exactly do you know the TOB's were bad? Like what is the issue I need to look out for in order to know if I need to replace my TOB?

 

I dont remember where it leaked from on the tob itself, but the lnf bearing completely leaked all the brake fluid overnight. Couldve been shop installation error but i cant be sure. All i know is i have had luck with lsj tobs and will continue to use them.

I had an act clutch for a bit, but when i ran the lnf bearing, it was with the gmpp clutch upgrade.

I forgot that they offered spacers, but maybe that was all it needed. I dont know how i would measure that though. I have a difficult enough time getting the trans back in lol

 

x2, i've done it many times, they will be fine.

 

U need a new tob. Why does zzp put the rev limit so high, that's at threshold for the stock head. Scary

 

I do to.

Because it's better to set it at 7200 and tell them to rev to 6800 and shift. It's worse to bounce off it on these cars. Breaks things.

 

Ran mine at 7400 to keep me from dropping off too bad on the 1-2 shift. It will survive if the driver is at all competent.