: Cadillac STS-V Shift Flare



Guy.Seminerio
05-31-13, 10:05 PM
When I go from 3-4 on moderate acceleration at around 25-30 mph, car takes longer to shift. During the shift RPMs jump a bit and then come back down as if its finally "catching." This noticeably and annoyingly disrupts forward movement. A fellow member identified this as "shift flare" and recommended I disconnect the battery for a few hours and see if that solved the problem. I disconnected the battery overnight, reconnected it this morning, and the problem still exists. Any other ideas before I take it to the stealer? By the way the problem is either intermittent, or I'm not doing the exact thing that causes it every time (amount of throttle, exact speed before shifting gears, etc.)

carter's_sts
05-31-13, 10:37 PM
Normally I would say check the Trans fluid, but we know that story.

Guy.Seminerio
05-31-13, 10:59 PM
Haha yes those who aren't following, just had the Trans fluid flushed by the stealer. And this is an issue I've been having since I purchased the car, so before and after the Trans fluid flush.

Dave G
06-01-13, 08:48 AM
I get it on the 2-3 shift only when it's cold. Once the car gets warmed up, it shifts as it should. It seems more like a stock trans tune issue.

TimmyC
06-01-13, 11:12 AM
I get it on the 2-3 shift only when it's cold. Once the car gets warmed up, it shifts as it should. It seems more like a stock trans tune issue.

That is an issue with a seal inside the transmission. Once it warms up it works properly but before that it leaks. The only real fix is the updated seal and shaft.

A tune should help the 3-4 flare. I do not know the root cause of that.

Cadillac Cust Svc
06-01-13, 11:31 AM
When I go from 3-4 on moderate acceleration at around 25-30 mph, car takes longer to shift. During the shift RPMs jump a bit and then come back down as if its finally "catching." This noticeably and annoyingly disrupts forward movement. A fellow member identified this as "shift flare" and recommended I disconnect the battery for a few hours and see if that solved the problem. I disconnected the battery overnight, reconnected it this morning, and the problem still exists. Any other ideas before I take it to the stealer? By the way the problem is either intermittent, or I'm not doing the exact thing that causes it every time (amount of throttle, exact speed before shifting gears, etc.)

Hello Guy.Seminerio,

I apologize that you are experiencing this “shift flare” in your STS-V. Although you are reaching out to the community for opinions, I would like to extend my assistance in working with the dealership since you stated you might take it in. If this is something that you would like, please send me a private message with your name, contact info, VIN, mileage, address, and dealership you are working with. Thank you very much for your time and I look forward to assisting you with this concern.

Gregory W.
Cadillac Customer Care

Guy.Seminerio
12-11-13, 09:36 AM
3-4 flare solved with a simple reflash if the TCM.

theotherguyssn
12-12-13, 11:55 AM
mine does it on occasion usually cold also just performed a transmission flush yesterday on the car and feels way better make sure fluid is at proper level if you have a lift and can check it lol gotta love gm not putting a dipstick on these cars lol

CMNTMXR57
12-12-13, 12:22 PM
I was gonna say, this has nothing to do with the transmission itself. It is a tune issue, and in particular, calculated load values (how it determines torque), based on inputs from the MAF. Get the most up to date flash from GM and/or get a quality tune. I'd also clean the MAF, especially if you're using an oil based filter such as what comes with the Spectre or a K&N. The thermistors in the MAF, over time, get coated with "soot" from this oil and can cause errant readings. IF worse comes to worse, do an idle re-learn procedure.

When I get one of those RPM spikes during shifts, I know it's time to clean the MAF.

Ludacrisvp
12-12-13, 12:24 PM
gotta love gm not putting a dipstick on these cars lol
GM doesn't do it on many if any cars these days ... introduced too many "backyard mechanics" that would introduce dirt and other contaminants (magic transmission fix in a bottle type crap too) and likely people overfilling the transmission due to improper checking of the level.

CMNTMXR57
12-12-13, 12:28 PM
I was gonna say, this has nothing to do with the transmission itself. It is a tune issue, and in particular, calculated load values (how it determines torque), based on inputs from the MAF. Get the most up to date flash from GM and/or get a quality tune. I'd also clean the MAF, especially if you're using an oil based filter such as what comes with the Spectre or a K&N. The thermistors in the MAF, over time, get coated with "soot" from this oil and can cause errant readings. IF worse comes to worse, do an idle re-learn procedure.

When I get one of those RPM spikes during shifts, I know it's time to clean the MAF and it works every time. Our MAF's are very sensitive to airflow over them it seems (hence why it is a drop in cartridge style vs. the typical GM barrel design), in regards to directional air flow with a Supercharger and potential sudden changes in airflow when boost is suddenly stopped.

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GM doesn't do it on many if any cars these days ... introduced too many "backyard mechanics" that would introduce dirt and other contaminants (magic transmission fix in a bottle type crap too) and likely people overfilling the transmission due to improper checking of the level.

Also, a transmission is a sealed unit. It doesn't burn oil/fluid, so the only option is leaking. If it ain't leaking, it's got sufficient fluid.

However, you can pseudo check it. It requires you getting it up on a lift, leaving it running so that the pump on the trans is running, pulling the drain, and you should get a light stream or drip immediately. If you get this, it has adequate fluid. If you do this without it running, you will take a shower until you get the bolt/plug back in.

Guy.Seminerio
12-12-13, 08:51 PM
Cmnt my understanding is that the method you describe above of how to check the fluid in the tranny is the actual way you're supposed to check it.

Now I had my Trans fluid drained (not flush, drain) at Cadillac a couple of months back and I have no leaks. Well when I took it in to get the tcm reflash I also had them check the Trans fluid. The bill shows that they added 1/2 quart. So that's the other thing they did.

Also, cmnt, remember the po171 and po174 that you gave me a lengthly description on how to combat? Well these codes have been very intermittent. On for a drive or 2, off for about 10-15, repeat.

What I'm going to try is to clean the maf and see if that does anything, so funny you mentioned that.

Also, I may have spoke too soon. Today I got it once on the 3-4.

My commute is work, home for lunch, back to work, back home. 4 miles each way. About 16 miles a day. Let's say 20 for incidentals. I would normally see the flare about 4 times per day. That's a majority of my accelerations from 0. Since I've had the reflash and top off of fluid, it's happened 1 time in total. Hopefully that maf cleaning will put the nail in the coffin on both issues.

beyerch
12-24-13, 05:47 AM
In regards to not having a dipstick, that's great it is a sealed unit and all, but I have no way of knowing what previous owners / services may have done. If someone dropped the pan and replaced a filter or if it was leaking in the past, how would I know. I prefer to check my fluid...

Just saying.... Interesting on the TCM reflash though, I'll take a look at that.

YoungBlood_STSV
12-24-13, 12:39 PM
I'd also clean the MAF, especially if you're using an oil based filter such as what comes with the Spectre or a K&N. The thermistors in the MAF, over time, get coated with "soot" from this oil and can cause errant readings.

CMNTMXR57: How do you go about cleaning it? Soft cloth? A drop of alcohol or something more mild?

Guy.Seminerio
12-24-13, 12:51 PM
What I did is buy maf sensor cleaner from autozone. Brand is CRC. When you pull the sensor you'll see some vertical metal rods in it. These sense the airflow I guess and even if they're clean looking, they might still need cleaning. You just follow the instructions on the bottle. You basically spray at them from all angles for I think it was 15-30 seconds. Then let it dry which is pretty fast. Then put it back.

On another note this didn't solve my problem and I also understand sometimes cleaning isn't gonna do it and you just need a new one. So that's next for me.