Disclaimer: The following is for informative purposes only and not intended for use. Under no conditions will the author, ls1tech.com or other host be held liable for use or misuse of this information. Always maintain safe practices, use jack stands and follow tool manufacture's prescribed instructions. Do Not Attempt.
Tools needed:
Torque wrench
Punch set
Good Snap ring pliers
-inner and outer, Sears carries a decent selection
Jaw Pullers, at least 6" & 8"
T40 torx bit
Assembly lube/grease
2.5" PVC pipe
Marker
4qts ATF + some to soak the blocker rings, either save some that came out or another qt.
To lighten things up, drain the transmission, use a 3/8" square ratchet.
The T56 holds 4qts of fluid. ATF Dextron/Mercon III, IV is a revision and is compatible.
"Until the mid-2006 model year, all six-speeds will be produced filled with DEXRON III fluid, although the transmission has been validated for used with new DEXRONŽ VI. In mid-2006, the six-speeds will come filled with DEXRONŽ VI, which was developed to behave more consistently during temperature and other environmental variations, as well as to provide even lubrication of the moving surfaces of the transmission."
-SIX-SPEED MANUAL TREMEC T56 (MM6/MZ6//M10/M12) CAR TRANSMISSION 2006 Model Year Summary-
Disassembly:
Remove shifter:
Remove the 4 hex perimeter bolts and remove the entire shifter as a single unit
Punch out Roll pin in shifter saddle and set aside.
Remove:
vent tube bracket and vent tube
(11) 5/8" bolts from the adapter plate- behind slave
-leave 1-2 bolts part way in and pry the plate loose using the designated prying notches
Stand transmission up with the input shaft facing down,
-put the input shaft through a hole in a table, the bellhousing and a couple blocks also works
Remove:
(8) 5/8" bolts from the tail-housing and lift tail-housing off
Start tearing down the beast:
Remove:
Rubber seal
Snap ring
Vehicle speed rotor, use gear puller
Snap ring
-a bit down the shaft
snap ring
spacer
bearing, roller type
spacer
snap ring
(74) thrust washer
(73) gear, reverse
(72) bearing, reverse needle
(71) wave washer
(70) brass blocker ring, for reverse gear
(69) Snap ring
(68) thrust washer
(67-62) Synchro Assembly
5/6 gear removed
Remove
Snap ring, above the reverse fork, pull up on the synchro sleave and fork and take off as a single unit, set aside.
(61) 5/6th gear
Snap ring on 5/6th fork
Countershaft extension and 5/6th fork as a single unit, (Note the orientation of the thrust washer under the countershaft extension)- set aside
Remove:
(2) T40 torx, shifting guide bolts from the side of the transmission
(4) bolts and take off the shift guide plate
(shift guide bolts)
after the guide plate is off, punch out the rolling pin holding the front offset lever (below)
Now we are ready to take off the main case.
The underside of the front offset lever contains a spring loaded ball that rides in the shift detent assembly. When pulling the main case off, hold the end of the offset lever down as the shift rail comes out. It's easier and also helps the ball not go flying off somewhere.
Slip the main case off.
Take a moment and look how the shift selecting pin and interlocking plate work together.
Note the vertical slot on the 5/6th shift rail lever (left,#144 slot not shown) and the horizontal slot on the interlocking plate (right,#156). We'll have to line these up when the shift guide bolts go back in.
Remove:
5/6th shift lever and rail as one unit.
-You can just go at it from here, but everything comes out nicely if you'll slide the sychro sleeves towards the up position. The countershaft then can easily be slid out.
Mainshaft, shift rail and forks, take out as one unit. Note how it looks, this will go back in as one unit.
From here the mainshaft must be take apart from both ends, a divider can be seen after removal of the 3rd gear.
Flip the mainshaft upside down on the stubby end, (right side of pic below)
-leave the bearing on unless you're replacing it.
(Starting left- large tapered bearing, 1st gear, 1/2 synchro, 2nd gear, 3rd gear, 3/4th synchro. Divider pointed out)
Remove:
Snap ring
3/4 synchro
-Pull 3/4 synchro sleeve off, either tap it off or use a puller
-Pull the synchro hub with a gear puller
Blocker ring
3rd Gear and caged needle bearing, (keep up with the bearings and where they go)
Spacer
Now we're done with the stubby end, flip the mainshafter over.
Remove:
Rubber o-ring, use a very thing tool and carefully remove it, use care not to tear it.
Bearing, (large tapered bi-directional load, input shaft)
1st Gear and caged needle bearing
Snap ring
Thrust washer
Inner cone
Friction cone
Blocker ring
(1/2) Synchro, again remove sleeve then use a gear puller for the splined hub
-Kent-Moore offers a long gear puller for some $$$, but if you're a budget racer like myself, if you're rebuilding your own transmission you probably are, then you can improvise.
Shown below, a couple of 8" and a 6" pullers combined
Tape them so they'll stay together.
note, the 6" puller is oriented wrong in the first pics
Continue removing:
Blocker ring
Friction cone
Thrust washer, (looks like a sprocket)
2nd Gear and caged needle bearing
Mainshaft Disassembly complete:
Back to the Countershaft Extension:
Remove:
Thrust washer, (should have already been removed when extension came out, black thing at right end of pic)
6th Gear and needle bearing
Blocker ring
Spacer
Snap ring
Synchro Assembly- (again tap off sleeve and pull the hub, separated sleeve and hub shown below)
Continue removing:
Blocker ring
5th Gear and needle bearing
Countershaft disassembly complete:
Synchros:
Lay the snychro hub down flat and put the keys into place.
-Notice there's there's humps on the back of the keys, now look at the sleeve; there's indents on the sleeve where the keys must go.
Put a spring into the slot of a key and go either direction.
-The springs are all different, but go according to size of the synchros. A large, medium, and two smaller sets.
-If you're using billet keys, there won't be a slot in the key, go just past the key for spring placement.
-The springs go 2/3 the way around, therefore both sides must go the same direction for whichever direction you chose.
Flip the synchro over, start a spring and go the same direction.
-There's slots on the blocker rings that must line up with the keys upon assembly, it's self explanatory when you look how it goes together.
-You'll notice in the pics that I've marked all the blocker rings and synchro sleeves, so there's no guessing involved.
The reverse gear synchronizer key retainer:
The reverse gear only engages only on one side, and can be flipped over during install for the fresh face of the sleeve which provides better engagement. Thus, there is a key retainer in place of the blocker ring on one side. See: Service Manual: page 29, part #67
Clean the splined parts and grease them up prior to assembly. This way you won't need a press, some will go on by hand or with minimal effort from a hammer and the PVC pipe.
Soak the blocker rings in ATF fluid for 20 minutes or more prior to installation.
Countershaft:
Now begin putting parts back together:
5th Gear and grey needle bearing
Blocker ring
Synchro Assembly
-Remember to line up the keys with the slots on the blocker rings.
Snap ring
Spacer
Blocker ring
6th Gear and brown needle bearing
Thrust washer- has a lip,
-Orientation- lip goes flush against 6th
below - correct orientation of the needle bearings, (grey left, brown right)
Countershaft Assembly Complete:
Mainshaft Assembly:
Starting with the longer end:
2nd Gear and caged needle bearing
Thrust washer, (sprocket type)
Friction cone
Blocker ring
(1/2) Synchro
-Slide it on if you can, otherwise get out the 2.5" PVC pipe and tap it on with a hammer.
Blocker ring
Friction cone
Inner cone
Thrust washer
Snap ring
1st Gear and caged needle bearing
Bearing-(the large tapered race)
Rubber o-ring
You should now have something that resembles this.
Turn over to stubby end and start putting on
Spacer
3rd Gear and caged needle bearing
(3/4) Synchro Assembly
-line up 3rd gear side's blocker ring with the synchro
-4the gear's side will be line up when the mainshaft goes back on the input shaft, when setting up the adapter plate (2 pics down)
Snap ring
The mainshaft at this stage.
edit: The grooves on the sliders should face down. Below, the grooves on the (3/4) slider are facing the wrong direction; I had to take it off and flip it.
-thanks to nine-eight for the correction
Set the input shaft and adapter plate up like so,
Go ahead and put the (5/6) shift rail assembly back in and 4th gear with the appropriate blocker ring.
-scrape off the old silicone
Put the countershaft into it's socket
Set up the mainshaft with the shift rail assembly and forks, such that you can put it in as on piece.
Slide the forks up and slide the mainshaft back in, then slide the forks back to the neutral position.
-If the sleeves over extend, simply tap them back into place. With a little persuasion/force they will slide back over the keys, taking it apart and reconfiguring is not necessary.
Turn the mainshaft so the notches on the 3/4 synchro and 4th gear blocker ring will line up and find their positions.
-It will fall into place; you can visually check it, if you marked everything.
The 5/6 shift levers interlock, line them up with the shift select pin.
You're ready to slip the main case on.
-run a bead of silicone
-use sparingly, the tolerances are tight
Apply lube to the ball to make things stick.
Slip main case on and position the front offset lever to sit on the ball while sliding the shift rail through.
(Note the ball sticking to the detent with grease)
-front offset lever not shown.
Here we are
Put the shift guide bolts back in, use a flashlight to look for the slots they fit in.
(2) T40 torx,
countershaft extension and 5/6 fork
-It was assembled as a whole unit prior, put it back on with the fork in position as a single unit (the protruding base of the fork faces down)
-Be sure to get the correct orientation of the lipped thrust washer, the lip sits flush against the 6th gear
Snap Ring on 5/6 fork
5/6 gear
-It's splined, tap it on with the PVC pipe
Synchro Assembly
Thrust washer
Snap ring
Brass blocker ring, for reverse gear
Wave washer
Bearing, reverse needle
Gear, reverse
Thrust washer
Snap ring
Spacer
Bearing, roller type
Spacer
Snap ring
-a bit up the shaft
Snap ring
Speed rotor, tap on
Snap ring
Rubber seal
Slide the tail housing on. If you can't get it quite on, it's probably because the 5/6 shift rail isn't lining up with the tail shaft socket. Use a long thin tool to pull it towards the right, and towards you; when you get it right, it should fall right into place.
Drive the roller pin back through the shifter saddle.
Torque Specs:
Tail housing bolts, 26ft.lbs,
Bell housing, 37ft.lbs
Shifter and guide plate, 15ft.lbs
Adapter plate bolts 11ft.lbs
Drain plug 26ft.lbs
-corrections/input welcome
%%% edit %%%
A number of people have contacted me about fixing the leak between the tail housing and the main case. Here you go.
Fix Leak Between Tail housing and Main Case
Remove shifter:
Remove the 4 hex perimeter bolts and remove the entire shifter as a single unit
Punch out Roll pin in shifter saddle and set aside.
Stand transmission up with the input shaft facing down,
-put the input shaft through a hole in a table, the bellhousing and a couple of blocks will also work
Remove:
(8) 5/8" bolts from the tail-housing and lift tail-housing off
clean surface, reapply silicon
Slide the tail housing on. If you can't get it quite on, it's probably because the 5/6 shift rail isn't lining up with the tail shaft socket (look at the inside of the tail housing and you'll understand). As you're sliding the tail housing on, use a long thin tool to pull it (the 5/6 shift rail) towards the right, and towards you; when you get it right, it should fall right into place.
Drive the roller pin back through the shifter saddle.
bolt up tail housing bolts to 26ft.lbs
put the shifter back on. 4 perimeter bolts @ 15 ft. lbs
"A true hotrodder wouldn't be content until he had created a car so violent, so hairy, so totally sick that the very act of dropping the hammer would result in instant death. Anything less results in the need to go faster." - Tony DeFeo
Very nice writeup!
I've rebuilt a couple of these and there's really not much to it........HOWEVER---the 5/6 driven gear on the mainshaft will determine how smoothly your rebuild goes. You may be one of the lucky ones and the gear will come off easily using a puller without damaging any teeth, the first trans I rebuilt was like that. The last one I did was an absolute nightmare.....I broke 2 heavy duty pullers, several teeth off of 5th gear and finally ended up having to cut that f*cking 5/6 gear off (keep in mind that gear costs $200). It also took heat and a 20 ton press to install the new gear......so be aware DIY'ers, that scenario is a possibility.
The only other advice I'd give to a first time rebuilder would be to lay all of the parts out in the order you take them off so everything stays organized, and get a copy of a service manual....the exploded views will make sure you get everything back where it's supposed to be. Also, don't install the old snap rings......a new kit is only $30.
Wow, that seems rather complicated. There's a lot more crap in there than I previously thought. I have a fealing my trans is crapping out on me though. I'll keep this in mind when it comes time to rebuild it. Thanks for the write up.
IF you replace a synchro assembly..Is there a specific side ...how to tell or does it mater
It doesn't matter on the side, the reverse can actually be flipped for a fresh face. Just be sure to line up the detents on the inner part of the sleeve with the humps on the keys.
got my heads/cam car sitting dead in the water right now because the tranny is locked in third and have been thinking about doing this.
To rebuild the tranny to say, hold a 1k hp (looking to the future), where can a master rebuild kit be bought to bring the t-56 up to spec to handle that kind of power and what kind of money would i be looking at spending?
now that this is up, i think i'm not the only one with this question.
is this also saying that to rebuild a transmission, this is all that there is to it? I was always under the impression there was alot more to it.
Last edited by Elcaballoloco; 05-23-2008 at 09:03 PM..
Wow, that doesn't seem as bad as I thought. Did you replace any of the bearings? I've "heard" that it is not recommended unless they are bad or damaged.
__________________ 91 Z28 LS1/T56...still in progress
But it moves under it's own power now!! 99NBM Camaro stockish...lid, lts, etc.
It doesn't matter on the side, the reverse can actually be flipped for a fresh face. Just be sure to line up the detents on the inner part of the sleeve with the humps on the keys.
I am really glad to see this writeup since im in the process of doing this myself. honestly, I really do appreciate anything I can find. I still dont understand why someone who is proficient with the T-56 hasnt made a rebuild video and sold copies of it online yet.
However, on a side note, and strictly coming from a guy who is gathering whatever he can from various write-ups online, Ive found an article where Joe from sixspeedsinc.com is photographed while rebuilding a T-56, and he makes a point in one photo to tell you that the small grooves that run around the circumference of the sliders should always point towards the front of the transmission, I.E. towards third gear on the mainshaft. Take it for what it's worth, I personally couldnt tell you jack about these transmissions based on experience, and I mean no disrespect by coming in and adding any doubt to your answer above.
if you have any interest in that rebuild article, search for "Joe Amber t-56 rebuild" under google and you should find the article by GM High Tech Performance as the first thing that pops up. Maybe I misunderstood the meaning of the caption on the photo, even though it is cleanly written and seems straight cut.
However, on a side note, and strictly coming from a guy who is gathering whatever he can from various write-ups online, Ive found an article where Joe from sixspeedsinc.com is photographed while rebuilding a T-56, and he makes a point in one photo to tell you that the small grooves that run around the circumference of the sliders should always point towards the front of the transmission, I.E. towards third gear on the mainshaft. .
Yeah, you are supposed to do that, I'll put that back in. I wrote it up a couple of months after the rebuild, so my memory was a bit off.
thanks
edit: As I recall the grooves lie only on the (1/2) or (3/4) slider ring. It maybe both but definitely not the reverse.
Quote:
Originally Posted by fast377
Did you replace any of the bearings? I've "heard" that it is not recommended unless they are bad or damaged.
I didn't replace the bearings, IMO it's not typical in a rebuild to do so. The stockers are Timken's and they'll probably last longer than anything else in there. Only the higher end kits have Timkens, considering the general trusts them and they're American parts, I would feel more comfortable leaving the them in, rather than replacing them with a cheaper foreign brand.
To rebuild the tranny to say, hold a 1k hp (looking to the future), where can a master rebuild kit be bought to bring the t-56 up to spec to handle that kind of power and what kind of money would i be looking at spending?
Rebuild kits (without bearings) should include the following:
Synthetic lined blocker rings
Synchro springs
Seals
Stock keys
Plastic fork pads
Shifter saddle bushing, (the socket the shifter rides in)
-And expect to pay about $200 shipped
If you want to build it above stock specs, 30 spline Viper output shafts run at about $250 as opposed to our 27 splined mainshafts. GM updated the MM6 shaft in Z06's to a 32 spline unit as well as a one piece countershaft; that's probably a better bet than viper spec.
$50 Billet keys, replaces stamped parts (optional)
$30 Bronze fork pads, replaces the plastic pads, common problem (recommended)
$50 3/4 Steel fork, replaces aluminum fork, common problem (recommended)
$110+ each synchronizer assembly (1/2) (3/4) (5/6), reverse can be flipped
Synchros are optional; the need to replace is denoted by grinding gears, although as per the service manual it may also be due to; bell housing misalignment, shift forks, clutch disengagement issues, pilot bushing, or damaged gears. Thus it could be suggested to inspect the synchros before replacement. The teeth should be close to sharp as possible, any rounding will make for harder shifts but it is usable according to the manual. Otherwise if they're chipped, they definitely need to be replaced.
Bearings are optional, expect to shell out $250+ over the cost of a basic rebuild kit for Timkens, cheaper brands can be had for less.
There's a kit and parts supplier that's well known here on the board, but they're not a supporter of tech so they'll remain unmentioned. T56 rebuilds is another supplier, a sponsor and known for having great customer service.
There's a debate over the use of certain synthetic fluids, it seems to tear down the stock paper based lined blocker rings but the carbon/kevlar lined rings don't seem to have a problem. As of 02' all T56's got the updated rings.
"Last year the 6-speed received carbon blocker rings on its synchronizers, increasing the durability of the transmission." -That was printed in the 03" model year summary
Quote:
Originally Posted by Elcaballoloco
is this also saying that to rebuild a transmission, this is all that there is to it? I was always under the impression there was alot more to it.
Once you tackle it there's not much to it, organization is key.
thanks for the right up. very nice piece. definitely sticky worthy.
__________________ Project BLU BIRD
1999 Trans Am
6speed,Arrival Blue
408 w/all the goodies...... o yeah and a new arrival blue paint w/pearl in it. Finally prowling the streets of Orlando.
man, this is just what the doctor ordered...I just picked up a TA on Tuesday that pops out of reverse...I hadn't rebuilt a tranny since school 20 years ago, so I was a little intimidated by the T56. Looking at this write-up, it doesn't look that bad. good deal! Thanks for taking the time to do it!
__________________ 98 Ford Explorer AKA Hoops 97 Trans Am M6 AKA Jessica Sold 98 Trans Am 383 M6 AKA Chuck Norris Sold & Missed
T56 Rebuild "how to" write up 
(shift guide bolts)
