Anybody having trouble with T56 shifting?

[RebekahsZ]

I've posted questions in several other forums and found tons of posts like mine on the LS forums, but I have yet to find somebody who can recommend a good, permanent or even semi-permanent fix. I'm getting clutch dust into my clutch hydraulics. My problem is perfectly described in these two videos at these websites:

 

 

 

Somehow, the throwout bearing is collecting dust. I am not leaking any fluid. I completely flushed my clutch hydraulics and the car shifted great until 2 hours into a road trip. It only seems to mess up clutch disengagement during high rpm shifting under full load (drag race style driving). Car shifts fine when babied around in regular traffic.

 

I'm trying to find a fix for this. Folks have tried replacing every component of the hydraulic system without solving the problem, including the throwout bearing. Guys seem to initially think they have solved the problem, then a few posts later the problem returns. Looks to me like this flushing technique works, but who the heck wants to have to bleed the hydraulics every couple of hours of driving or after every 3 runs at the strip???

 

I'll listen to any suggestions. I'm thinking about some sort of big hole in the bell housing (there is just a tiny hole in the bottom) to let dust vent out easier?? Maybe even a big fan to blow it though?? Possibly an external slave cylinder with a clutch fork modification??

Edited August 21, 2012 by RebekahsZ

[ColtGT4g63]

How do you know that dust is getting into the fluid? What kind of clutch set up do you have? did you buy it new or used? I had a problem back in the day with my Datsun where I heated up my disk really good. There was this gel material that surrounded the springs in the clutch disk, which ended up melting off after I cooked it really good. It fell in between the lining material and the PP / Flywheel and caused some disengagement problems. ended up replacing the disk with a new one and didn't have any more problems after that. I never touched any of the hydraulics in the system. Only exception was bleeding the clutch whenever the fluid would turn black, which was pretty often.

[SUNNY Z]

Have you checked the adjustment of your master cylinder? I'm about to change mine a little. It refused a 1-2 no lift at 7K - which should have been gravy.

 

Generally, the pushrod will need to be lengthened in this event. ^^^^ In order to facilitate more separation

Edited August 22, 2012 by SUNNY Z

[RebekahsZ]

GT45, it is definitely clutch dust. I just heated up some of my new fluid on my stove and it stays brown, albeit darker brown when heated. The fluid turning black is clutch dust. If I park the car for a few days, the fluid clears up and the dust settles to the bottom of the master reservoir. Mine is turning black after only a short trip daily driving. If I bleed it out, my clutch operates normally. Give it a few blasts down the road to get some dust mixed in and the clutch goes crazy. I'm starting to consider a LT1 T56 swap to get the throwout bearing outside of the bell housing away from the dust. I'm glad you didn't have trouble with it, but I was hoping you had a solution. Sounds like you were a frequent bleeder - thats how I'm gonna handle it in the short term. So far, everybody I've talked to with a LS/T56 has trouble with black brake hydraulic fluid. I have a 100% stock 18K-mile GTO clutch system with a 1" Tilton master cylinder with a Speedway AN line and remote bleeder. Not slipping a bit, so long as I have clutch adjusted properly.

 

SUNNY, I'm building a firewall to inner fender clutch master brace. You may be getting the first taste of what I am dealing with. I've been adjusting the heck out of my linkage. To get it to disengage when it starts hanging up I have to increase my clutch travel all the way up, which makes it really hard to control. Carrying a cut-off 7mm wrech everywhere I go. For that 3-4 gear shift, the pedal is back down low, so it is up, down, up half way, down. Impossible to be consistent-that's why I'm all shook up.

Edited August 22, 2012 by RebekahsZ

[NewZed]

I wonder if you could have the metal sealing surface plated and/or polished so that the seal would work better. The dust must be sitting in some porosity or machining marks that the seal doesn't wipe clean, and getting picked up by the fluid once it gets past the seal.

 

If the seals on a gas-filled shock absorber shaft can stay clean and maintain a gas charge while wiping dust, grime and water away, it seems like a good seal should be possible there. GM might have cut a corner and produced a product for the average user, not the abuser.

[RebekahsZ]

I think that is EXACTLY what is happening. Been burning google up looking for somebody with a fix, but I'm still looking. I got to find an association of Ls stick drag racers. Or switch to an auto trans, but where's the fun in that? Starting to research alternative manual trans options for the Ls motor but Im starting from a zero knowledge base. Any experiences welcome.

[SUNNY Z]

You just need to fix what you have. Don't even think about switching trannies. haha

 

Go post up on LS1tech in the manual trans section, or at least search over there. 4th gen F-bodies are extremely problematic with stock hydraulics - they have the exact symptoms that your car does. Pedal sticking, missing gears, hard to get into gear. Generally the fix is a new upgraded master cylinder. They usually go to a tilton unit, which has a billet mount built by tick performance. Those guys know 6 speeds, and are great to talk to. I wouldn't hesitate to call them for anything - super knowledgeable.

[h4nsm0l3m4n]

It seems like all the tick performance fix is a using an overly large master cylinder and allow you to adjust the pedal to where it engages the clutch at all speeds. Going off this idea, what master cylinder size have you been using? Have you considered bumping up a bore size or 2? This should be relatively painless to install since they just bolt right in and are pretty cheap. Once you are moving more fluid you may have more success in adjusting the clutch pedal to work at all speeds.

 

What this fix doesnt seem to address is the problem of dust getting into your clutch fluid. Instead it covers it up and makes it a less visible issue. I dont have the expertize to say whether this would an problem long term or not but I imagine frequent bleeding would probably still be advisable since your fluid will continue to be contaminated by the high rpm shifting.

Edited August 22, 2012 by h4nsm0l3m4n

[johnc]

Why not go to a Tilton hydraulic release bearing?

 

http://www.tiltonracing.com/sites/default/files/editor_uploads/files/Tilton2012%20-%20Hydraulic%20Release%20Bearings.pdf

[RebekahsZ]

Now we're getting somewhere. Suuny, I'd sure like to fix what I got- I love the gearbox. Im on my third master cylinder- it ain't the problem. Ticks uses the same mc I already have. They just put a rod end in it which won't fit the z pedals. I've tried 3/4, and one inch, going back a notch to 7/8 this weekend. After studying this and spending lots of time surfing the Ls sites I really think ranger acceleration has the correct diagnosis as a bad slave/ throw out design. I agree with the comment above about wipers on the seals and how shocks do the job adequately. all the aftermarket cutch companies sell GM throw outs or copies. Gonna look into johnc rec and see if tiltons throw out is somehow fundamentally different in design. The throw out system is the problem.

[SUNNY Z]

This whole site is a good read. However, this particular section pertains here.

 

http://www.rangeracceleration.com/Clutch_Care.html

[zdlite]

GM put a small restriction in the stock clutch line feeding the HTOB to slow the release of fluid in an effort to force people to shift more slowly. This reduces stress on the stock drivetrains improving the warranty situation. The "drill mod" is pretty common over on ls1tech to restore power shifting performance. If you truly have a "100% Stock" clutch system then you might try doing this mod.

[Leon]

GM put a small restriction in the stock clutch line feeding the HTOB to slow the release of fluid in an effort to force people to shift more slowly. This reduces stress on the stock drivetrains improving the warranty situation. The "drill mod" is pretty common over on ls1tech to restore power shifting performance. If you truly have a "100% Stock" clutch system then you might try doing this mod.

This isn't going to help as it affects clutch engagement, not disengagement.

[RebekahsZ]

Guys, thanks for the suggestions, keep them coming because I haven't found a solution yet. I've talked to a couple of the road racers in our forum/club. They all have black clutch hydraulic fluid. But, if the shift frequency is at the daily driver or even the road race tempo, the dirty fluid doesn't seem to affect performance. It seems to only affect performance when shifting at the full throttle "bam,bam,bam" frequency of drag race shifting. I've PM'd JustaFantaZ to see if he's having trouble, but haven't heard back. Waiting for feedback from Racer240z and ColtGT...both of whom I know wound up changing to auto trans.

 

SUNNY - I found that rangeracceleration website; it is one of the two videos in my opening post. Unfortunately, I don't want to flush my hydraulics after every run - I want to hot lap every night I go to the track in order to get some practice in and get better. For now, I plan to flush before every trip and just quit and go home when I start getting shift refusals. Hope I don't break anything with a missed shift...I'm looking for a legit FIX for the problem. I can black the fluid in one trip around town. I am confident that Ranger has the problem identified, but I really want a legit fix, not just a service frequency that is basically to service the hydraulics after every time I drive the car. Haven't been able to find a phone number for Ranger. BTW-what color is your hydraulic fluid?

 

zdlite - I found that one in my research, too, thanks. I didn't tell the whole truth about having a stock system: the master cylinder is a Tilton and I have a Speedwaymotors.com braided line to the slave cylinder; the slave, PP and clutch disc are stock 2006 GTO with 18k miles. I am changing to a 7/8 master tonight and flushing the system again. I will do the little test of inserting a 1/8" drill bit into the line to ensure that it complies with the "drill mod" instructions. Unfortunately, there are lots of posts on LS1tech where the drill mod didn't fix the problem. In fact, I can't find a single follow-up post where somebody claims to have solved the problem, just lots of complainers like me.

 

Per johnc's recommendation, I called Tilton to talk to tech about their throwout bearings. The rep imagined from my description that GM must have left a "wiper seal" off of the configuration/design of the throwout bearing to knock the dust off the sleeve that the throwout bearing rides on. He suggested looking into the Tilton 400 and 800 series thowout bearings to see if they can be used. He says his bearings do incorporate a wiper seal.

 

I went by the local GM dealer. They had no LS1 or LS2 thowout bearings assemblies in stock for me to examine in order to better understand the problem. They cost $262 and the closest one is 3 hours away. Autozone can order the bearing itself, but not the slave cylinder assembly.

 

Called SPEC clutch. The rep on the phone was not aware of a problem with blackening of the hydraulic fluid. He asked around the office while I was on hold and nobody was aware. They sell the GM throwout bearing.

 

Monster clutch uses a GM throwout bearing. They deny knowledge of the problem.

 

Called McLeod's. Their rep was aware of the problem. They have a throwout bearing that is totally different from the stock one and incorporates a wiper seal. Unfortunately, it is compatible only with their clutch setups, so I'd need to make a big investment to buy one of their whole kits. Anybody with experience with their stuff, please chip into the conversation, cause I'm tempted to sink the cash.

 

I'm gonna do the frequent flush plan for now and keep studying for a solution before I take the car completely off the road. In the meantime, I'm gonna be studying McLeods and Tilton's setups. McLeods is gonna be expensive; Tiltons is gonna require me to learn how to mock up a clutch system properly and cobble together individual parts to work (or not work) together (very intimidating for me). I'm also interested in learning if it is possible to adapt an LT1 T56 bellhousing to my GTO LS2 transmission and make it bolt up to the LS2 engine. That would move the slave outside the bellhousing and operate the throwout with a clutch fork. Anybody with LT1 to LS experience, please chip in!

 

All this while holding down a fulltime job!

Edited August 23, 2012 by RebekahsZ

[SUNNY Z]

Keith, first off, quit that notion of putting an LT1 t56 in..... its not really an option, and if it was, it would be uber expensive.

 

The slave cylinder / TOB is the same across the board. I ordered one from GM, one from Tick Performance, and one from napa. The napa and GM ones had the identical part numbers.......... , and the one from tick was a carbon copy. There are literally THOUSANDS of these on the road, with no issues. I would replace the one you have (i know the napa one carries a year warranty - I should "break" mine once a year lol)

 

You need to start talking with people that actually race t56 cars. Start with Tick Performance - best customer service and knowledge of t56s that I've ever talked to. Go to LS1tech, and look in / post in the manual trans section. Some of the worlds fastest t56 cars live there, and the people that build them.

Edited August 23, 2012 by SUNNY Z

[mark]

2002 ls1 t. 56. Road race the shIft out of the car. I have a quartermaster twin dIsc set up with there slave and Tilton master. I don't think I have ever bled the clutch after it was put tOgther 6 years ago.

 

Now I'm ashamed. I must go bleed my clutch.

[RebekahsZ]

mark-who makes the quartermaster clutch (which company?). When you go out to your car, could you please inspect the fluid in the master reservoir and tell me how it looks?

 

sunny-I been search'in like crazy and will continue. Found some interesting stuff in LS2GTO.com with more complaints, but no answers. I'll look more specifically in the sections you reference. What's your theory for the shift refusal you had the other day? I've seen you bang thru the gears-it ain't the operator!

[johnc]

who makes the quartermaster clutch (which company?

 

That be... Quarter Master. http://www.quartermasterusa.com/

 

I ran their 5.5" Pro Series and never had a problem.

[rsicard]

 

RebekahsZ:

 

 

 

A T56 for an LT1 can be used with a LSx engine. The LT1 T56 has a shorter input shaft than the one used for the LSx engine. Get the input shaft replaced with the longer one for the LSx engine. It is common place for hydraulic throw-out bearing to get clutch dust into the fluid line to the bearing. I have a LT1 T56/SBC and will purchase a Quicktime Steel bell-housing as a safety measure containing a clutch explosion. The slave cylinder is external of the bell-housing and therefore should not have the darkening of the clutch fluid do to clutch dust infiltration. I already have the pull type slave cylinder from McLeod for the standard GM LT1 T56 bell-housing. You don't need to go to a Quarter Master Clutch system.

[RebekahsZ]

Riscard,

 

Actually, what I was thinking about was to just change from an LS2 bellhousing for an LT1 bellhousing. I would want to keep my gearbox and my engine. Will the LT1 bellhousing attach to the LS1 or 2 engine block? The goal would be to keep all else the same, but step back a generation and move my clutch hydraulics to outside the bellhousing to keep them clean. What do you think?