Cadillac CTS-V Forum banner

1 - 14 of 14 Posts

·
Registered
2018 Cadillac CTS-V; 2002 BMW E39 M5
Joined
·
14 Posts
Discussion Starter · #1 ·
I'm having an issue with my V. I started developing the rumble strip noise, so I took it into the dealer to get the transmission service. While they were at it, I had them balance the tires. Now, I have a fairly pronounced vibration/rough ride in the car.

Changing from Sport to Tour mode makes little difference on the ride quality. On fairly smooth concrete roads the vibration is minimal but still pronounced, and on the freeway, it's quite obvious.

I've had the car back to the dealer three times to rebalance, and it's only been marginal improvements. The dealer then did a road force balance test on the rear tires, and got 30 and 33 lbs for left and right rears. They said that these are slightly out of spec, and suggested buying new tires. They're giving me a 50% discount under warranty since the vehicle has just over 15k miles.

What are the right specs for road force tests? Should I have them looking at something else? Should I buy the tires? Help me, wisdom of the forums!
 

·
Registered
2017 Cadillac CTS-V
Joined
·
460 Posts
They're screwing you into buying shit you don't need. You need the A8 trans flush done to solve the issue with the stock fluid's viscosity in humidity. Dealer should do it,no questions asked, and know what it is by now, since it's been happening across the ENTIRETY of the GM line using ANY A8 trans. They've probably done HUNDREDS. There is a TSB out on it. All the info you need is accessed using the search feature of this specific forum.




 

·
Registered
2018 Cadillac CTS-V; 2002 BMW E39 M5
Joined
·
14 Posts
Discussion Starter · #3 ·
I know about the trans flush, and had that done. That was the second line in the post. The issue is that, after I had them do the balance, I'm getting a rear end vibration that they now can't fix.
 

·
Registered
Joined
·
31 Posts
Torque Converter?

I'm just guessing at that from all the threads referring to the Trans Flush......

So take that for what it's worth......
 

·
Registered
2018 Cadillac CTS-V; 2002 BMW E39 M5
Joined
·
14 Posts
Discussion Starter · #5 ·
Is there any way to troubleshoot that on my own? I was thinking maybe if I pop it into neutral while I'm going down the road it would reveal something? However when I do that there's no change but I'm not sure if that's a valuable diagnostic or not.
 

·
Registered
Joined
·
113 Posts
If it’s TC you’d notice some slippage while shifting (M6 or A6) and decreased performance, at least that’s my experience. And yes vibration from the shudder in trans.
 

·
Registered
2018 Cadillac CTS-V; 2002 BMW E39 M5
Joined
·
14 Posts
Discussion Starter · #7 ·
I do notice that the shudder is worse when a lift off the accelerator. Or, for example, when I turn off cruise control and let the car decelerate.

I'll try some shifting up and down and see if I notice any slipping.

I'm assuming "decreased performance" is something substantial? With as much power as these cars have, I'm not sure I'd notice a loss of a hundred ft-lbs or hp, haha!
 

·
Registered
Joined
·
113 Posts
I do notice that the shudder is worse when a lift off the accelerator. Or, for example, when I turn off cruise control and let the car decelerate.

I'll try some shifting up and down and see if I notice any slipping.

I'm assuming "decreased performance" is something substantial? With as much power as these cars have, I'm not sure I'd notice a loss of a hundred ft-lbs or hp, haha!
To elaborate basically it’ll feel sluggish and accelerate slower than usual but yes with 556 crank horsepower it’d still scat even if sluggish down low
 

·
Registered
2017 Cadillac CTS-V
Joined
·
460 Posts
Torque Converter?

I'm just guessing at that from all the threads referring to the Trans Flush......

So take that for what it's worth......
I was thinking same. That TQ converter is toast, valve body probably done too.
 

·
Registered
2018 Cadillac CTS-V; 2002 BMW E39 M5
Joined
·
14 Posts
Discussion Starter · #10 ·
I was thinking same. That TQ converter is toast, valve body probably done too.
How can I do a better job of troubleshooting that? Or at least asking the dealer to troubleshoot?
 

·
Registered
2017 Cadillac CTS-V
Joined
·
460 Posts
Man, I'd love to be able to tell ya. Short of being able to replicate the issue, they're going to deny replacement. Early in the transmission saga, they'd replace converters and valve bodies hoping doing so would fix the issue. When those remedies didn't, they stopped offering them, and went back to flushes until they discovered the correct trans fluid.

My buddy bitched so bad about his Denali they replaced both, and GM even had their engineer come out to NJ to diagnose. But remember, this was back in '17.

Since they now have the fluid fixed, you're facing an uphill battle. You need to press the issue that they can't determine the amount of damage utilization of the wrong tranny fluid caused to the Tq converter and/or valve body and/or clutches.
 

·
Registered
2018 Cadillac CTS-V; 2002 BMW E39 M5
Joined
·
14 Posts
Discussion Starter · #12 ·
There's no problem replicating the issue. It happens every time I drive it at almost any speed. At certain speeds the vibration is more or less intense, but it's always there.
 

·
Registered
2017 Cadillac CTS-V
Joined
·
460 Posts
There's no problem replicating the issue. It happens every time I drive it at almost any speed. At certain speeds the vibration is more or less intense, but it's always there.
Does it do it even in neutral while coasting?
 

·
Registered
2018 Cadillac CTS-V; 2002 BMW E39 M5
Joined
·
14 Posts
Discussion Starter · #14 ·
Does it do it even in neutral while coasting?
Shifting to Neutral doesn't change it. When I'm coasting in neutral, I still feel the vibration.
 
1 - 14 of 14 Posts
Top