C6 Transmission durability?
Thread Starter
Pro
Joined: Dec 2009
Posts: 688
Likes: 18
From: Seattle Wa
C6 Transmission durability?
Hey Guys,
So I have to ask... My C5 had a dying transmission at 60k miles... I was running a CAI, Catback and a 100 shot (426whp when on the juice). (only used probably 6 refills on a 10lb bottle). The power as I understand it shouldn't have been an issue for the tranny as there are people running far more power through sc or turbo and not having the same issue.
I was SHOCKED when I brought it in for it's service and they told me it was done. It had started slipping but I thought that it was just due to the fact it was due for it's tranny service.
It was an auto too as is the C6 (I drive in traffic a fair amount so I avoid sticks).
I do switch between D and 3rd fairly often as anytime I'm going to get on it I don't like to do it from D. I don't know if that hurts anything or not.
Although I got a warranty this time I'd like to avoid the same issue and I still don't understand how my tranny failed so early on the C5.
Is the C6 tranny any more durable?
So I have to ask... My C5 had a dying transmission at 60k miles... I was running a CAI, Catback and a 100 shot (426whp when on the juice). (only used probably 6 refills on a 10lb bottle). The power as I understand it shouldn't have been an issue for the tranny as there are people running far more power through sc or turbo and not having the same issue.
I was SHOCKED when I brought it in for it's service and they told me it was done. It had started slipping but I thought that it was just due to the fact it was due for it's tranny service.
It was an auto too as is the C6 (I drive in traffic a fair amount so I avoid sticks).
I do switch between D and 3rd fairly often as anytime I'm going to get on it I don't like to do it from D. I don't know if that hurts anything or not.
Although I got a warranty this time I'd like to avoid the same issue and I still don't understand how my tranny failed so early on the C5.
Is the C6 tranny any more durable?
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
First, the '05 4L65-E received several upgrades/enhancements over the 4L60-E in the C5. From the Museum website:
I haven't seen any complaints of early, unanticipated "wearing out" of the '05 A4 trans. Certainly could have missed some or forgotten but I don't think it's an issue. Like any slushbox auto trans, you do have to keep an eye on the condition of the fluid and maintain it correctly.
Durable 4L65-E delivers automatic performance:
The available automatic transmission in the C6 is the new Hydra-Matic 4L65-E four-speed. An upgraded version of the C5’s 4L60-E, the “L65” is strengthened and revised to accommodate the LS2’s 400 lb.-ft. of torque.
To beef up the internals, a five-pinion planetary gear set was added – replacing a four-pinion gear set. The extra gear reduces friction and loads carried by all the gears. The washers between the gear sets are made from Teflon, allowing optimal operation at high speed.
For protection from the high temperatures that are generated by high speed, a four-plate oil cooler has been added. When the transmission fluid reaches 127 degrees Celsius (approximately 260 F), the torque converter lock does not disengage, except briefly during shifts. This prevents fluid shear in the torque converter from adding heat to the transmission.
The 4L65-E uses a highly advanced electronic controller that has been specifically calibrated for Performance Algorithm Shifting. This technology automatically selects the optimal gear for a given driving condition, making it a willing accomplice for performance driving and hard cornering. The 4L65-E transmission shifts at higher rpm, compared to the C5’s 4L60-E, to take advantage of the LS2’s higher horsepower and rev range.
The available automatic transmission in the C6 is the new Hydra-Matic 4L65-E four-speed. An upgraded version of the C5’s 4L60-E, the “L65” is strengthened and revised to accommodate the LS2’s 400 lb.-ft. of torque.
To beef up the internals, a five-pinion planetary gear set was added – replacing a four-pinion gear set. The extra gear reduces friction and loads carried by all the gears. The washers between the gear sets are made from Teflon, allowing optimal operation at high speed.
For protection from the high temperatures that are generated by high speed, a four-plate oil cooler has been added. When the transmission fluid reaches 127 degrees Celsius (approximately 260 F), the torque converter lock does not disengage, except briefly during shifts. This prevents fluid shear in the torque converter from adding heat to the transmission.
The 4L65-E uses a highly advanced electronic controller that has been specifically calibrated for Performance Algorithm Shifting. This technology automatically selects the optimal gear for a given driving condition, making it a willing accomplice for performance driving and hard cornering. The 4L65-E transmission shifts at higher rpm, compared to the C5’s 4L60-E, to take advantage of the LS2’s higher horsepower and rev range.
I haven't seen any complaints of early, unanticipated "wearing out" of the '05 A4 trans. Certainly could have missed some or forgotten but I don't think it's an issue. Like any slushbox auto trans, you do have to keep an eye on the condition of the fluid and maintain it correctly.
Le Mans Master
Joined: Dec 2005
Posts: 7,753
Likes: 210
From: North Western Connecticut
Perhaps there is a reason GM decided there will be no auto's in the Z06 or ZR1? Yes there are plenty using A6 tranny with more then stock power but the difference is those aren't tranny's aren't warranted either.... 
Melting Slicks
Joined: Oct 2004
Posts: 2,338
Likes: 175
From: Kernersville NC
Haven't seen issues with the A4. Mine has been fine but I'm not a real aggressive driver. My only concern would be the differential in the '05' if it was used for any kind of drag racing. If I dd that I'd beef it up with some of the availale support systems on the market. Mine's been a great car since new. Love 2nd gear in the A4.
