: What's wrong with my V? Trans?

08-14-13, 02:38 PM
2006 STS-V, sometimes has this weird problem in 2nd gear only at WOT. There's a lurch in forward momentum when this happens. This run was in comp driving mode, I tried a few pulls in M2 with stability off, and no problems at all, at least today. I've seen it happen with stability off too. As you can hear, the traction wasn't all that great on this surface. A hard downshift from about 50MPH into 2nd will cause this same problem.

I'd really like to get this fixed, been avoiding WOT so I don't kill the trans if that's the problem.


08-15-13, 11:10 AM
That's the worst I have seen. I think it's slip. And with the miles the car has I could beleave it.

Cadillac Cust Svc
08-15-13, 02:11 PM

We're sorry to hear you have a concern with the transmission on your STS-V. We know it's not necessarily an option for everybody, but if you do decide to work with a dealership to get this diagnosed, please keep us posted on that. We're available to provide additional support if you feel you should need it!

All the best,
Sarah (Assisting Greg)
Cadillac Customer Care

08-15-13, 05:46 PM
Do you have a good dealership around you? If so, I'd take it in.


Well actually with as little experience as there is regarding this engine, this will probably be the first time your dealer, or just about any dealer for that matter, will have seen this. This leads me to believe that they're going to recommend replacement of the transmission as opposed to trying to pinpoint the issue. Somewhere that specializes in transmissions that will actually try to troubleshoot instead of searching for a tsb and giving up might be a better bet. Although in the end, a new tranny might be the answer. Damn I hope not. Keep us posted.

08-15-13, 08:02 PM
I'm in Minot, North Dakota. I have one option for a dealership, Ryan GMC/Buick/Cadillac. Don't know how their reputation is, but I'd bet they have never seen an STS-V. I'm sure a 6L80 doesn't come cheap.

Strange that it was holding fine in M2, but not in auto CDM. I've seen it do this "slip" in M2 before though. Makes me wonder if there's something wrong in the TCM program.

Let me throw a wrench in this whole problem with this pull, just a day before the one in the OP. This was with stability off. http://www.youtube.com/watch?v=VSydvsjXcvA

08-15-13, 08:12 PM
My mom's mercedes had the same problem and the transmission was eventually replaced :-/ hope you find out that it's some much cheaper than that...

08-15-13, 09:38 PM
Well not sure what the Trans fluid temp was in the video on the op, but the engine definitely hadnt gotten up to operating temp. The 2nd video, the engine was at operating temp. That's the difference I noticed. How consistently does this happen?

08-15-13, 09:46 PM
Well not sure what the Trans fluid temp was in the video on the op, but the engine definitely hadnt gotten up to operating temp. The 2nd video, the engine was at operating temp. That's the difference I noticed. How consistently does this happen?

Trans temp was 155 in the first video, the engine oil temp was 190. The coolant temp gauge is shut down thanks to the stupid "engine hot - ac off" message. Need to change the thermostat, haven't got around to it yet.

08-15-13, 10:14 PM
Haha gotcha. There are a few guys on here that haven't posted yet who might be able to help you out, but so far your answer from 1madstsv is slip. A couple more will chime in soon enough.

08-15-13, 10:27 PM
so far your answer from 1madstsv is slip.

I really don't like that answer at all. Been digging around, seems like the G8 guys have some 6L80 problems that were solved with a trans fluid exchange and TCM reflash. That would be pretty expensive, but not quite the price of a new trans.

08-15-13, 11:20 PM
Ouch that doesn't sound good at all. That definitely sounds like slip to me.

08-16-13, 01:02 AM
Pull both negative and positive leads off the battery overnight and see if once you reconnect it see if the issues change at all. If there is any change you may need a reflash. If not you may need to talk to a transmission shop.

08-16-13, 03:22 PM
jack the car up and take the tranny plug off the pan. IF fluid comes out its full. IF IT DOESNT the tranny is low. mine did similar and the tranny was 1quart low. filled It up and no issues since. I would start there. the car must be on when your doing this.


6l80s are known for not being friendly when the fluid is low. that is not an expensive exchange to be honest. just start with checking the fluid level and go from there. if its low fill it up and see if that fixes it OR makes it better. I was told to over fill mine about a half quart so I instructed the shop to do that. as stated, mine was acting freaking goofy as hell and just filling It up slightly over the recommended amount fixed it immediately. HUGE difference.

08-16-13, 03:38 PM
Thanks for the pointers. I'll start with fluid and resetting the TCM. Might just have the dealer do an exchange on the fluid, it's about time for that, I drive pretty hard, and have had the car on a road course a few times.

I just don't see how the clutch pack could be shot, looking at the pull in post #5. I'd bet this slipping behavior could tear it up pretty fast though. My V is pretty much stock, I'd like to think that a 6L80 is strong enough to take a stock LC3.

08-16-13, 03:45 PM
your correct. the only issues youd have is if someone changed the trans tune and did it incorrectly. also, low fluids CAN cause wear and tear. I caught mine shortly after dealer did fluid exchange (double check their work ps..) and it was back getting filled up about 90hours later. plus I let them know how highly I thought of there great service.