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My 2002 Z06 race car had a sticky clutch during hillclimb practice last weekend. Looked under the car and noticed missing bolts at the bottom of the bellhousing and cracks:
Missing bolts between torque tube and bellhousing
I stopped there and trailered the car back home. I removed the cover tonight to assess the damage:
2 lower bolts were missing, 1 was completely loose
Bellhousing cracked all around
So, besides the bellhousing replacement that is obvious, do you think that there could also be damage to the torque tube and clutch (only 35k miles on drivetrain)?
I will have to take everything apart anyway to look at it, but as I have to order parts, I wonder if changing the clutch should be part of it too.
While you have it apart - at 35K miles, make it all new. New clutch, pressure plate, throw out bearing and add a remote bleeder. Spend a few $ and make it 100% reliable while you have it all disassembled. USE LOKTITE on the bell housing bolts !
While you have it apart - at 35K miles, make it all new. New clutch, pressure plate, throw out bearing and add a remote bleeder. Spend a few $ and make it 100% reliable while you have it all disassembled. USE LOKTITE on the bell housing bolts !
The remote bleeder is definitely going in. Any recommendation? (I have seen several threads but haven't picked one product yet)
I am reluctant to put a new clutch in as this is a race only car (non street legal) and I won't have any opportunity to break in the clutch. If the current clutch is not damaged I'd rather keep it but I'm not sure if there could be invisible damage.
How is the engine mounted? Rigidly or with rubber/urethane bushings?
Did you have any shiftability issues, primarily 3rd to 4th?
We don't deal with transaxle type applications often but I had both gearbox engineers and my lead builder (who is from NPG and did some really radical transaxle and front drive transaxles).
First thoughts:
-The engine and clutch cover wanted to rotate past the torque-tube couplers ability to compensate.
-Something forced the engine/clutch cover to tilt up
-The clutch cover wasn't concentric enough with the back of the crank
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Just some thoughts. Hope you get it ironed out in the near future. If you need gearbox parts, I can help you find a vendor close to home.
I have stock engine mounts so I guess they are rubber bushings. The whole engine and drivetrain is stock, I just have suspension mods and a lot of weight reduction.
Yes I had issues shifting into 4th and finally downshifting into 2nd when I caught this.
I had an impact on the front right last year with a big rock getting under the wheel (broken upper control arm) but I didn't notice any impact to the chassis or drivetrain after that.
Originally Posted by Auto Gear
How is the engine mounted? Rigidly or with rubber/urethane bushings?
Did you have any shiftability issues, primarily 3rd to 4th?
We don't deal with transaxle type applications often but I had both gearbox engineers and my lead builder (who is from NPG and did some really radical transaxle and front drive transaxles).
First thoughts:
-The engine and clutch cover wanted to rotate past the torque-tube couplers ability to compensate.
-Something forced the engine/clutch cover to tilt up
-The clutch cover wasn't concentric enough with the back of the crank
-------------------
Just some thoughts. Hope you get it ironed out in the near future. If you need gearbox parts, I can help you find a vendor close to home.
IMPORTANT!!! Replace the PILOT BEARING!!!!!!!!!!!! It will be compromised if not already damaged beyond service. Hopefully, your torque input shaft bearing isn't damaged. I would check that also
If it were me, I would spring for the new poly mounts and a PFADT rear differential mount.
When I installed my SPEC Twin Disk, I failed to notice a hair line crack in the bell housing until I was bolting the Torque Tube to the bell housing. Had to remove the bell housing again and order a new one from Gene Culley.
Mine was a just a hair line crack that could of possibly been re-welded. I didn't want to take the chance as I put that stuff under a LOT OF STRESS!
Examine the clutch, pressure plate and look for abnormalities. If there nothing glaring and no weird hot spots or TAPER WEAR on the disk, it is probably good to go.
At least it was just your bell housing. Six weeks ago I had the clutch in mine fly apart, took out the fuel lines and the car burned. You can fix that.
Here's the problem you;ll have, finding a torque tube that won't cost 3 grand. From my research, they aren't making them for the C5 any longer.
GENERALLY; If you have a 3-4 shift issue, we look for excessive bellhousing runout. In a traditional gearbox location, that bellhousing hole (called the register bore) needs to be essentially concentric with the crankshaft pilot bushing. Acceptable tolerance is .010" TIR (total indicator runout) for a street car. For a competition car, you want to see .005" TIR. However, Im not a C5 owner; so I am not coached up enough to give you advice on remedying that. All Im saying is you should check with an expert who understands bellhousing runout and see if it applies to your C5.
To dovetail with Mr Curlee above; pilot BEARINGS are not very forgiving of bellhousing misalignment, whereas the Oilite bronze bushings in our C1-C4 part of the world; can handle a slight amount of misalignment as the input pilot will just wear its own pocket in the bushing and relieve the stress.
What can happen to make the 3-4 shift difficult is that the 3/4 synchronizers sliding clutch is now doing double duty. It is not only acting as a synchronizer, but its also being forced to pull the input gear (4th gear) into enough alignment to allow the sliding clutch to engage the engagement teeth on the back of the input gear. This 'wobbling' will accelerate wear on the pilot, the sliding clutch, and the engagement teeth on the input gear. Eventually, the classic sign is that when you liberally apply your right foot to the loud pedal; the transmission kicks out of gear because the sliding clutch and the engagement teeth are all rounded over. But there is also some additional underlying concerns. T56s use tapered bearings instead of ball bearings. Tapered bearings do not like a lot of backlash and bearing damage can result if left unchecked long enough.
Not trying to be Chicken Little here, just trying to share some real world experience.
You DID say you had some impact damage; perhaps it started a hairline crack and finally let go.
GENERALLY; If you have a 3-4 shift issue, we look for excessive bellhousing runout. In a traditional gearbox location, that bellhousing hole (called the register bore) needs to be essentially concentric with the crankshaft pilot bushing. Acceptable tolerance is .010" TIR (total indicator runout) for a street car. For a competition car, you want to see .005" TIR. However, Im not a C5 owner; so I am not coached up enough to give you advice on remedying that. All Im saying is you should check with an expert who understands bellhousing runout and see if it applies to your C5.
To dovetail with Mr Curlee above; pilot BEARINGS are not very forgiving of bellhousing misalignment, whereas the Oilite bronze bushings in our C1-C4 part of the world; can handle a slight amount of misalignment as the input pilot will just wear its own pocket in the bushing and relieve the stress.
What can happen to make the 3-4 shift difficult is that the 3/4 synchronizers sliding clutch is now doing double duty. It is not only acting as a synchronizer, but its also being forced to pull the input gear (4th gear) into enough alignment to allow the sliding clutch to engage the engagement teeth on the back of the input gear. This 'wobbling' will accelerate wear on the pilot, the sliding clutch, and the engagement teeth on the input gear. Eventually, the classic sign is that when you liberally apply your right foot to the loud pedal; the transmission kicks out of gear because the sliding clutch and the engagement teeth are all rounded over. But there is also some additional underlying concerns. T56s use tapered bearings instead of ball bearings. Tapered bearings do not like a lot of backlash and bearing damage can result if left unchecked long enough.
Not trying to be Chicken Little here, just trying to share some real world experience.
You DID say you had some impact damage; perhaps it started a hairline crack and finally let go.
The C5/C6 bell housing is connected to the Torque Tube. The Torque is a RIDDGED mounted housing that contains a prop shaft. The TT connects to the Transmission/ differential assy.
The LS engines all have needle bearing pilot bearings and a re VERY susceptible to install damage and mileage wear. Seeing that damage, gave me the creeps as to WHAT THE HECK ELSE is damaged. If lefrog carefully inspects the TT and accesses and repairs any damages and replaces the Bell Housing and Pilot Brg, all should be good.
Again,, what caused the damage in the first place??? Like I stated, I would eliminate engine mounts and differential mounts right off the bat
Another thing that has been tried and blessed off as WONT WORK is the bronze and or the KEVLAR pilot bearings..
I have never seen the point of kevlar pilot bushings. Im surprised that oil-impregnated bronze doesn't work either, but I'll take your word for it. You are absolutely correct in that proper installation of a needle bearing is critical but so is proper bellhousing alignment.
I will probably end up putting a new complete clutch kit in with new pilot bearing.
Good call on the engine mounts, would the Hinson urethane be enough or should I be looking at solid mounts?
I guess Pfadt rear diff mounts are hard to come by since Pfadt disappearance, any other good source?
Emmanuel
Originally Posted by Bill Curlee
IMPORTANT!!! Replace the PILOT BEARING!!!!!!!!!!!! It will be compromised if not already damaged beyond service. Hopefully, your torque input shaft bearing isn't damaged. I would check that also
If it were me, I would spring for the new poly mounts and a PFADT rear differential mount.
I will probably end up putting a new complete clutch kit in with new pilot bearing.
Good call on the engine mounts, would the Hinson urethane be enough or should I be looking at solid mounts?
I guess Pfadt rear diff mounts are hard to come by since Pfadt disappearance, any other good source?
Emmanuel
Call Hinson... Im sure they will be more than enough. I picked up my PFADT mount used on the C5 Parts for sale (with the help of PATCHES)
I think Hinson has a PFADT Style mount or someone else picked up the design and is making them again although,,, they are a little more expensive than they were.
GENERALLY; If you have a 3-4 shift issue, we look for excessive bellhousing runout. In a traditional gearbox location, that bellhousing hole (called the register bore) needs to be essentially concentric with the crankshaft pilot bushing. Acceptable tolerance is .010" TIR (total indicator runout) for a street car. For a competition car, you want to see .005" TIR. However, Im not a C5 owner; so I am not coached up enough to give you advice on remedying that. All Im saying is you should check with an expert who understands bellhousing runout and see if it applies to your C5.
To dovetail with Mr Curlee above; pilot BEARINGS are not very forgiving of bellhousing misalignment, whereas the Oilite bronze bushings in our C1-C4 part of the world; can handle a slight amount of misalignment as the input pilot will just wear its own pocket in the bushing and relieve the stress.
What can happen to make the 3-4 shift difficult is that the 3/4 synchronizers sliding clutch is now doing double duty. It is not only acting as a synchronizer, but its also being forced to pull the input gear (4th gear) into enough alignment to allow the sliding clutch to engage the engagement teeth on the back of the input gear. This 'wobbling' will accelerate wear on the pilot, the sliding clutch, and the engagement teeth on the input gear. Eventually, the classic sign is that when you liberally apply your right foot to the loud pedal; the transmission kicks out of gear because the sliding clutch and the engagement teeth are all rounded over. But there is also some additional underlying concerns. T56s use tapered bearings instead of ball bearings. Tapered bearings do not like a lot of backlash and bearing damage can result if left unchecked long enough.
Not trying to be Chicken Little here, just trying to share some real world experience.
You DID say you had some impact damage; perhaps it started a hairline crack and finally let go.
I was thinking that too re: the impact damage, with the engine on "soft" bushings could have moved some. Maybe started a crack.
So here is an update on this. After taking everything apart, this is what was left of the bellhousing:
Bellhousing art!
The clutch and bearings were actually fine, it's the slave cylinder that took the rest of the hit:
Slave cylinder also took a hit
I replaced the entire clutch kit (bearings, flywheel, disk, mechanism) and slave cylinder. Note that the LuK clutch kit uses a different design for the flywheel/mechanism hookup and you cannot insert the mechanism with the bellhousing in place. The proper order is:
1. Bellhousing in place but bolts backed up as much as possible
2. Flywheel
3. Clutch disk + mechanism
4. Bellhousing bolt tightening
LuK clutch kit has a different flywheel design that prevents inserting the mechanism when the bellhousing is in place
I also replaced the motor mounts with poly ones. Hinson was out of stock so I went with the Level Zero Motorsport poly mount (95A durometer, $130 on eBay). For the rear, I went with the Pfadt/Hoosier torque limiting diff mount. It was also a good time to put a clutch remote bleeder. Had to do it twice because I didn't check that they didn't tighten any of the fittings and they were leaking... but once the torque tube is back in place, there is no room to get back there to tighten anything...
The new bellhousing and clutch were the cheapest on Amazon with 2-day free shipping with Prime!
New bellhousing in place
Everything is now back together. I was really happy with my 4-post lift + quickjack setup to do this job. I did everything as a 1 man job except to put back the rear cradle were I had 2 friends come over to help me finish the work. If you use 3 jacks under the car, 1 under the engine, 1 under the diff and 1 under the transmission, it is very easy to re-align everything and put the torque tube back through the clutch with minimal effort. The quickjack lifts the car enough from the 4-post ramps to do the job.
4-post lift + quickjack makes it possible to do this work as a 1-man job
$400 for engine mounts, thanks but no thanks.
And the car is a C5 not a C6, so you don't have diff mounts for it. The Hoosier/Pfadt torque limited diff mount which IMHO is a better design is cheaper too!
Bellhousing damage
Hopefully, your torque input shaft bearing isn't damaged. I would check that also
