What symtoms did you have prior to rebuild?
Pops out of gear, hard to get in gear, gets stuck in gear, grinding in low rpms, grinding in high rpms, notchy shifting (when it shifts)

Wheres a good place to get a rebuild kit for the T-56.
D&D Performance
Rockland Standard Gear
The Gear Box

My owners manual for 99 says dexron III, I see others referring to "GM synchromesh" or other synthetics or hybrids. Dealer parts guy never heard of it. Can you clear this up???
Here is the deal. Further research has determined that GM Synchromesh is safe for ALL T-56 transmissions. However, if you are seeing the strip, high rpm shifting in cooler climates may not be as smooth due to the viscosity mentioned below. HERE IS TEH PROOF! Others who work in the field will back me on this.
Pre '01 transmissions use paperlined blocker rings. Non-silicone based synthetic fluids will greatly shorten the life of your blocker rings by eating away at the paper fibers and you WILL have to have them replaced sooner. Post '01 trannys have carbon fiber lined blocker rings and it doesn't damage those. Your concern will be rust.
It also depends on how the car is driven. If it is a track machine stick with stock fluid, if it is a Sunday driver that hardly sees anything above 3,500 rpm then synthetic will be ok. Best bet is to just use what came in the tranny and leave it at that. M6's don't generate much heat or anything so basic fluid does fine regarding friction.

"GM synchromesh is not really a good fluid choice for any T56. It has a higher viscosity that can be detrimental to high speed shifting and would produce unacceptable shifts at lower temps( below 40 F)" -30THBIRD

GM Synchromesh is a Synthetic fluid. Synchromesh trans fluid p/n 12345349 $7.xx/qt. You will need 4 quarts if your tranny is bone dry. $30 dollars if you really want it.

Transmission shifting is notchy? What possibly causes this?
Partial notchiness is normal due to the design of the shifting patten design in side the tranny. It uses a spring and small ball bearing that moves between pits in a molded piece of steel. Notchiness can be one thing or a combination of things. Usually worn parts is the culprit. Most likely culprits are usually: throw out bearing, pressure plate, shift fork, gear blocker rings and rarely the shift links. Note if you are running synthetic and are on a pre 2001 trannmission or do not have carbon fiber blocker rings it is very possible that your paper lined blocker rings are deteriorating and are "sticking" to the gears.

Popping out of gear? What possibly causes this?
A bent shift fork causes this. If you still have a warranty take it to the dealer. There was a recall for this defective part (check the TSB). The original shift fork was aluminum and the replacement is steel.
No warranty? You can get prices from local shops and get the steel replacement for about $49 from D&D from the link above.

TSB bent fork info:
Transmission Jumps Out of 3rd Gear (Replace 3-4 Shift Fork, 3-4 Synchronizer Assembly, 3rd Gear Blocker Ring and 3rd Speed Gear) #01-07-29-003A
Transmission Jumps Out of 3rd Gear (Replace 3-4 Shift Fork, 3-4 Synchronizer Assembly, 3rd Gear Blocker Ring and 3rd Speed Gear)
1999-2000 Chevrolet Camaro/1999-2000 Pontiac Firebird
with Manual Transmission (RPO MM6)

This bulletin is being revised due to a change in part numbers. Please discard Corporate Bulletin Number 01-07-29-003 (Section 07 - Transmission/Transaxle).

Condition
Some owners may comment that the transmission jumps out of 3rd gear.

Cause
Condition may be caused by inadequate travel of the 3-4 synchronizer assembly due to the 3-4 shift fork being out of specification or bent.

Correction
Notice
Please review the appropriate section of the Transmission Unit Repair Manual for correct disassembly and assembly instructions. When performing this bulletin, ALL parts listed need to be replaced. The condition originally occurs because of the 3-4 shift fork being out of specification or bent. This eventually results in damage to the synchronizer assembly, the blocker ring and the speed gear.

Replace the 3-4 synchronizer assembly, the 3rd gear blocker ring, the 3rd speed gear and the 3-4 shift fork.

Parts Information
Part Number Description Qty
12523207 3-4 Shift Fork 1
12523078 3/4 Synchronizer Assembly 1
12523186 3rd Gear Blocker Ring 1
12523077 3rd Speed Gear 1

Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation Description Labor Time
K2752 Gear -- R and R or Replace - 3rd Speed Gear Use Published Labor Time

Stuck in 4th or any gear for that matter?
You just pushed the housing to far and the slider keys are now partially out and probably at an angle preventing the housing to slide back. Try to just jiggle the shifter and work it back over. You may try with the car on or off. "Rocking" is also an option. You don't want to force it because you will just do more damage or break your slider keys or both.

Hard to get in 1st or any gear for that matter? Most problems with getting it into gear is hydraulics. The master or slave are not functioning properly and not releasing or engaging. If your hydraulics are pre '01 then you need to upgrade. Why? The line was installed with a restrictor in it. The restrictor allows less fluid to move thru the line resulting in a slower reaction by the master and slave. Do TEH drill mod if you don't have the money to upgrade.

REGARDING REVERSE: Check this first. Open the lower fuse box (the one closer to the headlight). Look on the cover for the ENG SEN fuse. It should be blown. Replace it with a 20amp fuse. All done. Go start the car and try putting it in reverse. Worked perfectly for me. ~Jaspirr

Did you check the color of the plug? The reverse is a black solenoid plug/black harness plug. Th e skip shift uses white for bothe the solenoid and the harness (matched for easy ID). If these are reversed (mis-connected) you will get the prob you describe. It is also easy to damage the solenoid plug so be sure it is not broken. -30thbird

What's that Grinding noise?
That noise is your snychronizer slider keys grinding against the sleeve of the synchro housing followed by the gear blocker rings grinding next. This is caused by two things, either hydraulics are not functioning correctly and not allowing the clutch to fully engage or disengage. The other reason is that your slider keys are either very worn or one or more of them are already broken causing your sleeve to align incorrectly.

What is TEH drill mod???
Teh drill mod is a minor modification done to the steel braided line for the master cylinder. It basically involves drilling out a small restrictor in one end of the line that GM had put in there to lessen the amount of fluid passing through. Details on how to do this can be found here: TEH drill mod

What is TEH best way to bleed my clutch?
1. The Buschman's tutorial is the best method I have read about. I used it in my installation and have had NO problems. Highly recommended. You will use DOT 3 brake fluid. It is your "clutch" fluid.

2. The jmd method It's weird, he uses spark plugs and other things. The JMD method of bleeding should get your 1st thru 6th & reverse working better again. In short - bleed the hydraulics a bit whichever way you want 'til you're running clean fluid out of the bleeder. Get a 90 degree rubber boot from a spark plug wire. Fit rubber hose in it. Run it up to reservoir. Retain it in place so its end is under fluid. With the bleeder cracked, and the boot on the bleeder, you'll pump the pedal for a while. 5 minutes works for me.

Will a LT1/Viper T-56 fit in my LS1?
Yes and No. Yes almost any tranny will fit with MAJOR modifications and the right amount of money. Realistically? NO.
Check here for yourself.

How do other T-56's differ from the onein my LS1?
Application____________Input/Output Splines___Ft/Lb__1st___2nd___3rd__4th___5th___6th____Rev
GM Aftermarket_____________26 / 27__________400___2.97__2.07__1.43__1.00__0.80__0.62__3.28
5.0 Mustang Aftermarket_____10 / 31__________400___2.97__2.07__1.43__1.00__0.80__0.62__3.28
'93 - '97 GM F-Body_________26 / 27__________450___2.66__1.78__1.30__1.00__0.74__0.50__2.90
'98 GM F-Body______________26 / 27__________450___2.66__1.78__1.30__1.00__0.74__0.50__2.90
Viper(also GM and Ford) _____26 / 30__________450___2.66__1.78__1.30__1.00__0.74__0.50__2.90
'99 GM F-Body______________26 / 27__________450___2.66__1.78__1.30__1.00__0.74__0.50__2.90
4.6L Mustang_______________10 / 31__________400___2.97__2.07__1.43__1.00__0.80__0.62__3.28
2003+ Viper*_______________26 / 30__________550___2.66__1.78__1.30__1.00__0.74__0.50__2.90
*(TUET-1806 ONLY available through Chrysler)

How do identify the internal gears of my T-56?
Drive members
1st..........39
2nd..........43
3rd..........37
4th(input gear)..........31
5th..........58
6th..........67
Rev..........14 Idler..........23
Driven members
1st..........17
2nd..........28
3rd..........33
4th..........36
Rev..........35
From front to back in the trans 4th,3rd,2nd,1st,6th,5th,rev.

How much play is allowed on the input shaft?
A little bit is normal. The front end is supported by the pilot bearing. -jmd

Max end play should be .01 inch. max. on a used box. That being said, it is difficult for the untrained to measure this correctly. So a compromise is the side to side "feel". There should be some side to side play( this is NOT how endplay is measured) -30thbird

What is "Proshifting" in regard to the T-56?
Its where they take out the synchros and reduce the number of gears where the synchro rings are and it makes it easier to powershift. I just talked to them and they said it makes a bad street trans if you dont know what your doing, very loud and hard to shift at low rpms.
-jmd

What is this going to cost me?
Well more like what is it going to save you. Average prices for getting transmissions rebuilt start from about $1000 and go up from there depending on what you are doing. Even doing one gear with the exception of reverse (because it's all in the rear casing and you don't have to tear apart the entire tranny) and maybe 5th or 6th, you will have to take the tranny apart and that is where they get you for labor. Labor=$$$$ the parts are not that expensive.

What is the M6 shifter knob thread size?
F-body: M16 x 1.5
C5 Y-body: 9/16" - 18
C6 Y-body: Not internally threaded but can be tapped to M16 x 1.5. See this article for details.

What do I need to remove the pilot bearing from the crankshaft?
Pilot bearing removal tool: SK tools 92522 works great. Easier than a slide hammer in my opinion. -jmd



How may I increase the self-centering pressure on my Pro 5.0 T56 shifter?
Please read this excellent writeup by Y2K*WS6*TA This modification may be applicable to other shifters depending on their construction.

Where do I pick up a new pilot bearing?
GM dealer (the same one fits a huge variety of applications) if you're in a rush. It's an under-20$ item. Lots of vendors of them are to the right of this page also for when you pick up a new clutch from them ------------->

These threads for the guide bolts have locking compound in them. What threadsize are they?
It's not a bad idea to chase the threads in the maincase into which the two guide bolts thread. Start from the inside. The threadsize is M10x1.5.

Which Forks are iron and which are aluminum?
This applies for 100% of 93-02 F-bodies and should apply to all Y-bodies 97-02. I have worked on F-bod boxes from 1995 through 2002:

• 1-2: aluminum
  
• 3-4: aluminum OEM, replacement forks are iron
  
• 5-6: iron OEM
  
• reverse: iron OEM