Tremec Missed 1-2 shifts, Notchy

[Rick@RKT56]

Hello everyone. I am a newbie here but a member sent me an email to see if I can add some technical info regarding the TR6060 trans with 2nd gear issue. First, I am a Vette tech at a GM dealership and I do specialize in powertrain/drivetrain.

I have gone through over 15 TR6060's and the reason that this trans have issues with shifting into 2nd is the sintered bronze blocking rings. The Vette owners have the exact same issue ONLY when cold. The transmission doesn't grind when it reaches operating temp.

That being said, the older T56 transmission had compressed carbon blocking rings as a friction material and they performed fine. The newer sintered bronze is very "grabby" and causes sudden engagements of the blocking rings. I have contacted my source (Tremec distributor) and they told me that starting on 2010 models (Corvettes) the 2nd gear blocking rings have been changed to compressed carbon. To retro fit the redesigned blocking ring, you must also replace the 2nd gear as well. This info is from my source and I have no idea if/when GM will offer this as a SI (service information). I have searched for bulletins regarding the 2nd gear issue for the 2010 Camaro without success. There is a SI for the Corvette but it states that this condition is normal.

I have some pictures of the TR6060 I'll post later when I get a chance.

#PIP4357: Noise During The 1-2 Shift When Cold - keywords first grate grind second - (Feb 27, 2008)

Subject:Noise During The 1-2 Shift When Cold

Models:2009 Cadillac CTS-V - Tremec Transmission

Equipped With Tremec Manual Transmission RPO Code MG9

2008-2009 Chevrolet Corvette, Corvette Z06
Equipped With Tremec Manual Transmission RPO Code MM6, MZ6 or MH3

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

Some customers may comment about a Nibble or grate type noise that may also be described as a multiple bump feel during a 1-2 upshift event while the transmission is cold.
Recommendation/Instructions:

A new transmission synchronizer design was released for the 2008 and 2009 models listed above. The new synchronizer will make a noise when shifting from 1st to 2nd gear in temperatures at or below 32 degrees F.
This noise/feel is a normal characteristic and will go away after the transmission warms up. Warm up should occur after approximately 15 miles of normal driving. This condition requires no repair by the dealer.
The service technician should test drive the vehicle to verify the concern. If the noise/feel goes away after warm up no repair is necessary and the customer should be advised accordingly.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[MiSTER]

Thanks for replying back so fast Rick.

Originally Posted by Rick@RKT56

Hello everyone. I am a newbie here but a member sent me an email to see if I can add some technical info regarding the TR6060 trans with 2nd gear issue. First, I am a Vette tech at a GM dealership and I do specialize in powertrain/drivetrain.

I have gone through over 15 TR6060's and the reason that this trans have issues with shifting into 2nd is the sintered bronze blocking rings. The Vette owners have the exact same issue ONLY when cold. The transmission doesn't grind when it reaches operating temp.

That being said, the older T56 transmission had compressed carbon blocking rings as a friction material and they performed fine. The newer sintered bronze is very "grabby" and causes sudden engagements of the blocking rings. I have contacted my source (Tremec distributor) and they told me that starting on 2010 models (Corvettes) the 2nd gear blocking rings have been changed to compressed carbon. To retro fit the redesigned blocking ring, you must also replace the 2nd gear as well. This info is from my source and I have no idea if/when GM will offer this as a SI (service information). I have searched for bulletins regarding the 2nd gear issue for the 2010 Camaro without success. There is a SI for the Corvette but it states that this condition is normal.

I have some pictures of the TR6060 I'll post later when I get a chance.

#PIP4357: Noise During The 1-2 Shift When Cold - keywords first grate grind second - (Feb 27, 2008)

Subject:Noise During The 1-2 Shift When Cold

Models:2009 Cadillac CTS-V - Tremec Transmission
Equipped With Tremec Manual Transmission RPO Code MG9
2008-2009 Chevrolet Corvette, Corvette Z06
Equipped With Tremec Manual Transmission RPO Code MM6, MZ6 or MH3

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

Some customers may comment about a Nibble or grate type noise that may also be described as a multiple bump feel during a 1-2 upshift event while the transmission is cold.
Recommendation/Instructions:

A new transmission synchronizer design was released for the 2008 and 2009 models listed above. The new synchronizer will make a noise when shifting from 1st to 2nd gear in temperatures at or below 32 degrees F.
This noise/feel is a normal characteristic and will go away after the transmission warms up. Warm up should occur after approximately 15 miles of normal driving. This condition requires no repair by the dealer.
The service technician should test drive the vehicle to verify the concern. If the noise/feel goes away after warm up no repair is necessary and the customer should be advised accordingly.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[Rick@RKT56]

No problem. Here are some pics showing the difference between T56 and TR6060. These are Corvette trans and only thing different them other than the case/placement of the trans is the main shaft.























The engagement tooth are much smaller than the older T56. The T56 will take some missed shifts and just leave a mark on the tooth where as the TR6060 when missed will round the engagement tooth on the gear along with the tooth on the synchro ring.





Sintered bronze blocking rings. They are not as smooth as compressed carbon blockers from T56 IMHO.




This is from a 2010 Camaro with 1,200 miles. Guess what happened? Owner was racing and missed 2nd.

[MiSTER]

Rick... thanks for further explanation of what's going on with the TR6060. Welcome to the board BTW. Nice to have someone with your knowledge on the board. I know you've been a big help with your services/info on corvetteforum.com.

[Rick@RKT56]

Glad to be of help to fellow GM guys. I'll post if I see anything from GM.

[LT1Jeep]

Rick, can you tell from the list of parts i posted if the parts that were replaced were the same or upgrades like you mentioned? thanks.

[Rick@RKT56]

Originally Posted by LT1Jeep

Rick, can you tell from the list of parts i posted if the parts that were replaced were the same or upgrades like you mentioned? thanks.

I can't see some of the pictures at work so I can't see your invoice. The 2nd gear and ring part #'s are: 19256243 and 19256242 respectively. These part #'s are the same for 2010 and 2011 so there wasn't any changes made.

The carbon 2nd gear ring is available from my Tremec source but I very much doubt if GM will implement that in one of their bulletins.

If a board member lives near Baltimore MD, I would like them to come in the dealership and see what I can do with their TR6060.

[Milk 1027]

My 1-2 is fine. It's the 2-3 that I have trouble with . Cold or warm, it grinds all the time. I have to play with it and shift very slowly to get it to go in without a grind.

[Rick@RKT56]

Originally Posted by Milk 1027

My 1-2 is fine. It's the 2-3 that I have trouble with . Cold or warm, it grinds all the time. I have to play with it and shift very slowly to get it to go in without a grind.

As I have mentioned before since the enagement teeth are so small on the TR6060, once you miss few shifts, the teeth will get rounded off and will grind even in part throttle shifts. Only way to fix it would be to replace the gear/synchro and possibly the blocking rings.

[Rick@RKT56]

Originally Posted by LT1Jeep

Rick, can you tell from the list of parts i posted if the parts that were replaced were the same or upgrades like you mentioned? thanks.

I saw your list. One thing I noticed that was missing is/are the shims. The main shaft has to be shimmed so there isn't any end play (GM recommends 0.002" preload). I keep 2 of every shims size for my self just in case.

[Alain]

i'm gonna subscribe to this thread cause i'm having the same issues but mine is going from 2nd to 3rd gear. and sometimes it wont let me down shift into 2nd !!!

is it safe to say that it's being caused by the same reason, even though i have the problem mainly when shifting into 3rd gear??

[Rick@RKT56]

Originally Posted by Alain

i'm gonna subscribe to this thread cause i'm having the same issues but mine is going from 2nd to 3rd gear. and sometimes it wont let me down shift into 2nd !!!

is it safe to say that it's being caused by the same reason, even though i have the problem mainly when shifting into 3rd gear??

Only way to tell would be to open it up and see the insides.

[OUTATIME]

Originally Posted by Rick@RKT56

As I have mentioned before since the enagement teeth are so small on the TR6060, once you miss few shifts, the teeth will get rounded off and will grind even in part throttle shifts. Only way to fix it would be to replace the gear/synchro and possibly the blocking rings.

When you say you "miss" a few shifts, you mean that you let the clutch in/go too late or early and grinded? Or do you mean you mis-shifted?

[c_LoW29]

what dealer does Rick work at?