Stuck in fourth? HELP!?!?
Stuck in fourth? HELP!?!? Yesterday I was at the drag strip. I just made my pass and am coming up the return road. I tried to down shift, but I couldn't get it out of fourth. I finally forced it out and got it into third. After that it shifted into first through third fine. I went back to the pits. While holding the clutch in, I put the shifter into first through fourth. When I got it into fourth it would not come out for anything. I pushed the shifter forward as hard as I could, hitting it even, and it would not move out of fourth. Infact I'm still stuck in fourth. I had to drive a hour and a half home with only fourth!
Now what could have caused this? What is wrong with this crappy transmission? I just had third gear and the syncro replaced a couple months ago. Any help is greatly appreciated!
Now what could have caused this? What is wrong with this crappy transmission? I just had third gear and the syncro replaced a couple months ago. Any help is greatly appreciated!
Re: Stuck in fourth? HELP!?!? Well, odds are good that the little keys in the 3-4 slider gear have become dislodged from the slider, and are blocking you pulling the gear back in to neutral. I've seen a couple of trannies with these keys broken.
Here are some pictures.
http://www.akmcables.com/T56-1.jpg
This is the 4th gear assembly. Input shaft, a synchro, the 3-4 slider assembly, and a shift fork.
This is it assembled:
http://www.akmcables.com/T56-2.jpg
The slider gear moves back and forth to select 3rd or 4th. In the position above, it's in neutral.
Here is 4th gear engaged.
http://www.akmcables.com/T56-3.jpg
Note the black plastic pads on the shift fork. It's pretty common to see those broken. You can bend this aluminum fork when attempting to disengage the gear when it's stuck.
Now, here's the culprit. These little POS slider keys. They help keep the synchro in place, but they do like to pop out. Note this one - is popped out (I made it do that).
http://www.akmcables.com/T56-4.jpg
And finally, here are the little evil bastards, along with their springs that hold them in the slider gears.
http://www.akmcables.com/T56-5.jpg
Hope that helps.
Andrew
Here are some pictures.
http://www.akmcables.com/T56-1.jpg
This is the 4th gear assembly. Input shaft, a synchro, the 3-4 slider assembly, and a shift fork.
This is it assembled:
http://www.akmcables.com/T56-2.jpg
The slider gear moves back and forth to select 3rd or 4th. In the position above, it's in neutral.
Here is 4th gear engaged.
http://www.akmcables.com/T56-3.jpg
Note the black plastic pads on the shift fork. It's pretty common to see those broken. You can bend this aluminum fork when attempting to disengage the gear when it's stuck.
Now, here's the culprit. These little POS slider keys. They help keep the synchro in place, but they do like to pop out. Note this one - is popped out (I made it do that).
http://www.akmcables.com/T56-4.jpg
And finally, here are the little evil bastards, along with their springs that hold them in the slider gears.
http://www.akmcables.com/T56-5.jpg
Hope that helps.
Andrew
I can shift faster than you.
iTrader: (21)
Joined: Nov 2001
Posts: 5,133
Likes: 0
From: Baton Rouge, LA
Re: Stuck in fourth? HELP!?!? I would also add a severely damaged syncro can cause those problems as well. I actually had a defective syncro from Tremec in my last T56 rebuild right out of the box. The syncro would slide on the the driven gear, but would not come off without some prying. 
(you could shift into 2nd, but could not pull the shifter out of this gear) I swapped the syncro out and all was well.
Jason
(you could shift into 2nd, but could not pull the shifter out of this gear) I swapped the syncro out and all was well. Jason
Re: Stuck in fourth? HELP!?!? Very informative! Thanks a lot Camaroholic and Jason99T/A. I went ahead and took all of the nitrous out last night. I dropped it off at the dealership this morning to get it fixed under warranty. Hopefully it won't take them too long to get back to me. I'll post when I find out exactly what went wrong. Thanks again! 
TECH Addict
iTrader: (9)
Joined: Apr 2002
Posts: 2,085
Likes: 0
From: Texas, it's like your state, but better.
Trending Topics
I can shift faster than you.
iTrader: (21)
Joined: Nov 2001
Posts: 5,133
Likes: 0
From: Baton Rouge, LA
Re: Stuck in fourth? HELP!?!? LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Re: Stuck in fourth? HELP!?!? Heh, yeah, I just happened to have a parts T56 laying around out in the shop, so I grabbed the pieces and the digital camera. You know what the problem was with this parts T56 in the first place? Yep. Broken slider keys in the 3-4 gear slider. I have rebuilt a few T56's, so I had some extra slider keys laying around from those rebuilds. My own spare T56 also had broken 3-4 slider keys when I picked it up.
My personal least favorite part is the outside ring of the slider gear itself. They could've built that out of a harder metal. Those teeth get chewed up too easily, and at $125-$150 a pop to replace, they aren't cheap. And you can't buy just the ring, you have to buy the whole gear.
On my ST-10 (in the 79Z), the slider rings are $38 each, and the *entire* rebuild kit, including all bearings, races, synchros, gaskets, seals, new countershaft, etc was $150. But it was a bit tougher to rebuild. There were 88 needle bearings on the countershaft that you had to insert... one at a time... And hope they didn't fall out of the hole...
-Anderw
needle bearings
My personal least favorite part is the outside ring of the slider gear itself. They could've built that out of a harder metal. Those teeth get chewed up too easily, and at $125-$150 a pop to replace, they aren't cheap. And you can't buy just the ring, you have to buy the whole gear.
On my ST-10 (in the 79Z), the slider rings are $38 each, and the *entire* rebuild kit, including all bearings, races, synchros, gaskets, seals, new countershaft, etc was $150. But it was a bit tougher to rebuild. There were 88 needle bearings on the countershaft that you had to insert... one at a time... And hope they didn't fall out of the hole...
-Anderw
needle bearings
Teching In
Joined: Aug 2003
Posts: 8
Likes: 0
Re: Stuck in fourth? HELP!?!? Sorry to hear about your Trans. I am a pontiac tech who ends up working on all the Firebirds that roll in the door ( I just got good at taking them apart) there is a tsb for those 6 speeds for the problem you guys are having. TSB #01-07-29-003A the discription is for: Transmission Jumps Out of 3rd Gear (Replace 3-4 Shift Fork, 3-4 Synchronizer Assembly, 3rd Gear Blocker Ring and 3rd Speed Gear, but I have found it also cause the 4th gear sticking, the parts need for the car are:
12523207 3-4 Shift Fork
12523078 3/4 Synchronizer Assembly
12523186 3rd Gear Blocker Ring
12523077 3rd Speed Gear
I have done this for cars under warrenty and have never seen the cars in for the problem again, if you get your trans redone you should replace the 3-4 shift fork even if you don't have problems shifting. the new fork is new and does not lok like the pictures poted here. I don't have pics of the new fork or i would upload them. GM says the problem starts cause the fork bends. the trans them selfs are very strong but when the fork is bent 4th gear is engaded to far and 3rd gear is not enouf. thats what causes the problem. this is the only weak area I have found with these transmissions and wish you all well.
Ken
12523207 3-4 Shift Fork
12523078 3/4 Synchronizer Assembly
12523186 3rd Gear Blocker Ring
12523077 3rd Speed Gear
I have done this for cars under warrenty and have never seen the cars in for the problem again, if you get your trans redone you should replace the 3-4 shift fork even if you don't have problems shifting. the new fork is new and does not lok like the pictures poted here. I don't have pics of the new fork or i would upload them. GM says the problem starts cause the fork bends. the trans them selfs are very strong but when the fork is bent 4th gear is engaded to far and 3rd gear is not enouf. thats what causes the problem. this is the only weak area I have found with these transmissions and wish you all well.
Ken
Re: Stuck in fourth? HELP!?!? check it out first post sweet. anyway all i wanted to say was that my trans is in the shop right now for the same reason that this post was started.my trans went in the middle of my first pass at about the 1000 ft mark or just there after. went through the traps and was stuck in 4th. did the same thing you did pried on it for awile and it poped out the only thing is i fried what i thought was third and come to find out i fried all except 6th.oops. f it i'm goin with a 350 turbo.this will be the 2nd time in 13 mo it's been rebuilt.good luck man. 
Re: Stuck in fourth? HELP!?!?
blkmgc1,
when they rebuilt your trans did they replace the 3-4 shift fork?. It seams to be a weak point of the MM6 trans.
Ken
when they rebuilt your trans did they replace the 3-4 shift fork?. It seams to be a weak point of the MM6 trans.
Ken
.always was a fan of automatics anyway more consistant and no where near the hassle. 
Re: Stuck in fourth? HELP!?!? from what iv'e heard they are however i think i'm a little harder on them then most.however you are correct they can be upgraded to titanium gears and other junk as well(a tranny gut i'm not) but even then guys back home here still break stuff in them.little easier to fix though cause ya just brake 1 part not the whole thing.
Teching In
Joined: Aug 2003
Posts: 8
Likes: 0
Re: Stuck in fourth? HELP!?!? GM does not build the trans, its made by TTC and as they state "Currently, the TREMEC T-56 is being used on the Dodge Viper, Chevy Corvette Z06, Ford SVT Mustang Cobra, Aston Martin DB7 Vantage and V12 Vanquish, and Holden Commodore and Monaro."
but don't take my word for it here's a link to there web sight, and for those intrested they include and pdf for rebuilding the trans
it is the same thing you get when you buy it on ebay. and its free web page
good luck
but don't take my word for it here's a link to there web sight, and for those intrested they include and pdf for rebuilding the trans
it is the same thing you get when you buy it on ebay. and its free web page
good luck
Re: Stuck in fourth? HELP!?!? hey man i don't doubt it matter of fact your right i was talking to friend and the viper does have it.only one difference the internals are bulletproof.or better than the camaros.he had said that the insides were titanium.don't know a whole lot about tranys but i know titanium is stonger than what we have for that torque monster viper.
Teching In
Joined: Aug 2003
Posts: 8
Likes: 0
Re: Stuck in fourth? HELP!?!? if you look at the web page you can see the y make differnt trans with different torqe ranges witch I'm sure are for differnt applications. so i'm sure the Viper, Z-06 and SVT have titanium gears.
I don't have a problem with that or the torqe differance but the problem are not from the gears blowing up. it's from shifter/ syncro problem, thease part are alu. and brass. so titanium is not need it a stock or slightly beefed up F body.
I've got guys with stock cars still under warrenty beating the crap out of these syncros and bending shift forks. but not braking, chipping or cracking gears.
Ken
I don't have a problem with that or the torqe differance but the problem are not from the gears blowing up. it's from shifter/ syncro problem, thease part are alu. and brass. so titanium is not need it a stock or slightly beefed up F body.
I've got guys with stock cars still under warrenty beating the crap out of these syncros and bending shift forks. but not braking, chipping or cracking gears.
Ken
Re: Stuck in fourth? HELP!?!? I don't know where you guys are getting your information, but my BS-o-meter is on "PEGGED" for titanium internals on a Viper T56.
You can change the 'torque rating' of a transmission simply by changing the cut of the gear and the gear ratio itself. No need to change the metal. The 1993 F-body T56 had a lower torque rating than the 1994+, because of the different gearing. Not because of component strength.
AFAIK the only major differences are the steel 3-4 shift fork, and the carbon fiber synchro pad material. The input shaft and main shaft are likely different materials (and a different cut), but nothing is titanium from anything I've ever seen, heard, or read.
And titanium isn't necessarily stronger than a good steel. It's just lighter. It's used in valvetrain components to reduce weight. Not for strength. In fact, titanium valves are a bit softer than their stainless steel counterparts.
So again, sounds like a bunch of hear-say "I know a guy who told me" type info being passed around here. Post up facts, not "I think".
-Andrew
You can change the 'torque rating' of a transmission simply by changing the cut of the gear and the gear ratio itself. No need to change the metal. The 1993 F-body T56 had a lower torque rating than the 1994+, because of the different gearing. Not because of component strength.
AFAIK the only major differences are the steel 3-4 shift fork, and the carbon fiber synchro pad material. The input shaft and main shaft are likely different materials (and a different cut), but nothing is titanium from anything I've ever seen, heard, or read.
And titanium isn't necessarily stronger than a good steel. It's just lighter. It's used in valvetrain components to reduce weight. Not for strength. In fact, titanium valves are a bit softer than their stainless steel counterparts.
So again, sounds like a bunch of hear-say "I know a guy who told me" type info being passed around here. Post up facts, not "I think".
-Andrew