: Transmission won't downshift, '05 V8 STS4



tedasaurus
04-28-06, 01:22 PM
Particularly at higher altitudes. At 7,000k ft. and up the accel pedal must be pushed 1/2 to 3/4 to the floor just to get any downshift out of 5th gear. Then it goes to 3rd or 2nd and you get way to much accel. This really is a problem and nothing made up by too picky an owner. The problem is still there at lower altitudes but not as noticable. Help. My '05 SRX V6 works perfectly at sea and mountain levels just like all my other cars.

What is up? I am also not the only one experiencing this problem that appears to plague STS4 owners.

Thanks,

Jim Hailey
214 415 7373

urbanski
04-28-06, 01:29 PM
moved here
doesnt belong in open letters

chiefmjk
04-28-06, 08:35 PM
You can always put it into sport mode and shift the car manualy, it's fun. I have a 2005 STS 1SG with the adaptive cruise control and the heads up display which is great because it displays your tack when your in sports mode. Try it You'll like it.

tedasaurus
04-29-06, 08:13 PM
You can always put it into sport mode and shift the car manualy, it's fun. I have a 2005 STS 1SG with the adaptive cruise control and the heads up display which is great because it displays your tack when your in sports mode. Try it You'll like it.

The problem on my V8 STS4 is that when you shift manually there is a nasty/harsh driveline clunk every time you up shift regardless of speed or pedal position. Trust me it is so bad you will not want to do it often. I hear it is not that way in the two wheel drive versions, and it is not that way in my '04 SL500 or '05 SRX V6 awd, btw. Cadillac needs to spend some time on this or this is my last cadillac. Now. Literally. I have had eleven cadillacs and I am fed up. Lexus will be my next purchase unless this shifting can be fixed.

flyboy767
04-30-06, 09:02 AM
i have an 05 sts4 and it shifts fine in manual mode--no clunk--maybe a little slow for my personal preference, but it shifts fine.

jgrade
05-03-06, 03:13 PM
I've been wanting to play witht he sports mode, but don;t know the best rpm/spped to shift. What do you guys suggest? Does this effect the suspension at all?

05STSWOW
05-03-06, 07:37 PM
I have an 05 STS4 1-SG also with 34k miles and regularly experience a similar problem. When cruising along at low speeds (25-35 mph) in 5th with light throttle, if I hit a slight uphill grade, the car will actually 'buck' from lugging the engine before it will drop down to 4th. I often use 4th around town to eliminate this problem. It seems to not be as much of a problem in 'sD' mode while leaving to shift automatically. Manu-matic is fun, but not in traffic.
I had a computer 'flash' upgrade several months ago, but it didn't cure this problem. I wonder if it has something to do with the Performance Algorithm Liftfoot (PAL) shifting.
I did a Track Day at The Year One Experience at Road Atlanta a couple of weekends ago and it was a blast. Got to do two 10 lap stints, about 50 miles total. The PAL really works in these conditions as it senses agressive driving and holds the transmission in gear at about 5000 rpm even while letting off the gas, so no time is lost downshifting when you get back on it. I tried the manu-matic for a couple of laps, but found that the PAL kept it in the right gear most of the time. The brakes were great with no fade or smell. I had the suspension in Performance mode, traction control 'ON" (duh), A/C off and just left the tranny in sD. In could only pull about 110 mph on the back stretch and thought I could do more. I should have tried it in 4th to see if would be faster. My slow times were a direct result of my 'extensive' experience (watching other people go fast). Panoz's Audi S-4 school cars with instructors driving just blew past me, probably from being able to carry more speed through the turns (gotta practice).

tedasaurus
05-04-06, 12:19 PM
I have an 05 STS4 1-SG also with 34k miles and regularly experience a similar problem. When cruising along at low speeds (25-35 mph) in 5th with light throttle, if I hit a slight uphill grade, the car will actually 'buck' from lugging the engine before it will drop down to 4th. I often use 4th around town to eliminate this problem. It seems to not be as much of a problem in 'sD' mode while leaving to shift automatically. Manu-matic is fun, but not in traffic.
I had a computer 'flash' upgrade several months ago, but it didn't cure this problem. I wonder if it has something to do with the Performance Algorithm Liftfoot (PAL) shifting.
I did a Track Day at The Year One Experience at Road Atlanta a couple of weekends ago and it was a blast. Got to do two 10 lap stints, about 50 miles total. The PAL really works in these conditions as it senses agressive driving and holds the transmission in gear at about 5000 rpm even while letting off the gas, so no time is lost downshifting when you get back on it. I tried the manu-matic for a couple of laps, but found that the PAL kept it in the right gear most of the time. The brakes were great with no fade or smell. I had the suspension in Performance mode, traction control 'ON" (duh), A/C off and just left the tranny in sD. In could only pull about 110 mph on the back stretch and thought I could do more. I should have tried it in 4th to see if would be faster. My slow times were a direct result of my 'extensive' experience (watching other people go fast). Panoz's Audi S-4 school cars with instructors driving just blew past me, probably from being able to carry more speed through the turns (gotta practice).

That is exactly my problem, you described it far better than I. Cadillac needs to address this problem. Hopefully they will.

Tracks can sure be fun, with a little more practice I am sure you could keep up with a typically driven, shorter wheelbase, S4 in the turns.

Devil_concours
05-05-06, 07:44 AM
That is exactly my problem, you described it far better than I. Cadillac needs to address this problem. Hopefully they will.

Tracks can sure be fun, with a little more practice I am sure you could keep up with a typically driven, shorter wheelbase, S4 in the turns.
same issues here. Unless you go into manual and keep it in the lower gears, it struggles to find the right gear when driving around the neighborhood around 25mph.

S4 will still beat us. It's a lot more car than the sts on the track (ligher and more powerful)

commander112
05-05-06, 11:48 AM
Sounds like you guys are having the same issue that a poster by the name of Nasser is having. He has had no luck in getting it resolved. If you guys come up with a solution I'm sure he would appreciate a post on what was done.

Mark

tedasaurus
05-05-06, 04:51 PM
Sounds like you guys are having the same issue that a poster by the name of Nasser is having. He has had no luck in getting it resolved. If you guys come up with a solution I'm sure he would appreciate a post on what was done.

Mark

I have been in touch with Nasser in previous threads. Cadillac appears ignorant of our troubles. What is it going to take to get them to recognize the all wheel drive cars have a REAL issue.

tedasaurus
05-09-06, 11:46 PM
Drove the car today and cannot express my disappointment. The car HAS to be shifted manually at all times now in order to prevent hesitation and surging due to its inability to downshift. Don't know how much longer I can tolerate a $60k car acting like this with no attempt by dealer or cadillac to fix.

Devil_concours
05-09-06, 11:53 PM
I have been in touch with Nasser in previous threads. Cadillac appears ignorant of our troubles. What is it going to take to get them to recognize the all wheel drive cars have a REAL issue.
you think that's bad? check out all the threads in cts and cts-v forum regarding rear end issues

tedasaurus
05-20-06, 03:49 PM
To be more clear my STS4 will not accelerate at all in fourth or fifth gear if the rpms are below 2500 rpm. The car will stutter, hesitate, the tach will jump up and down, and then as you press the accel pedal nearly to the floor the car will then kick down to third or even second and you blast off. There is no in between and hills just make the problem more apparent. Cadillac dealers say there is no fix, and cadillac corporate won't reply. I am not the only one. I now drive my car in the city using the manual process to avoid the stumbling. If I wanted a stick shift car I would have bought one you know. Does cadillac really want my repeat business?

05STSWOW
06-20-06, 03:37 PM
I left my car and a copy of this thread at my dealer while on vacation. They took my complaint seriously and replaced the transmission torque converter. The warranty invoice said they found 'torque converter shudder' and it was a warranty repair. My service advisor said I should be very happy this was a warranty repair, as it was expensive, both in terms of labor and parts.
The difference is profound. Very smooth upshifts and my car pulls smoothly from low speed in 5th with barely discernable downshifts.
The work order had the following codes:
"36097 Torque Converter Slip/Shudder K7020 5.5 (hours, think) Replace Converter as per PIP3456B Flush Cooler - EB87E26".
I also was in for the 2005 SRX,STS Rear Suspension Campaign (inspect tow (sic?) link assembly. Mine was okay.
They also performed the SRX STS XLR Canister Purge Software Upgrade (Y0075 System Software Upgrade 06516). I have no clue what this is about.
Hopefully this information will help others with similar problems.

Devil_concours
06-20-06, 04:36 PM
I left my car and a copy of this thread at my dealer while on vacation. They took my complaint seriously and replaced the transmission torque converter. The warranty invoice said they found 'torque converter shudder' and it was a warranty repair. My service advisor said I should be very happy this was a warranty repair, as it was expensive, both in terms of labor and parts.
The difference is profound. Very smooth upshifts and my car pulls smoothly from low speed in 5th with barely discernable downshifts.
The work order had the following codes:
"36097 Torque Converter Slip/Shudder K7020 5.5 (hours, think) Replace Converter as per PIP3456B Flush Cooler - EB87E26".
I also was in for the 2005 SRX,STS Rear Suspension Campaign (inspect tow (sic?) link assembly. Mine was okay.
They also performed the SRX STS XLR Canister Purge Software Upgrade (Y0075 System Software Upgrade 06516). I have no clue what this is about.
Hopefully this information will help others with similar problems.
That's good to hear. Did the low speed studder get fixed too?

robhersch
06-21-06, 05:06 PM
I left my car and a copy of this thread at my dealer while on vacation. They took my complaint seriously and replaced the transmission torque converter. The warranty invoice said they found 'torque converter shudder' and it was a warranty repair. My service advisor said I should be very happy this was a warranty repair, as it was expensive, both in terms of labor and parts.
The difference is profound. Very smooth upshifts and my car pulls smoothly from low speed in 5th with barely discernable downshifts.
The work order had the following codes:
"36097 Torque Converter Slip/Shudder K7020 5.5 (hours, think) Replace Converter as per PIP3456B Flush Cooler - EB87E26".
I also was in for the 2005 SRX,STS Rear Suspension Campaign (inspect tow (sic?) link assembly. Mine was okay.
They also performed the SRX STS XLR Canister Purge Software Upgrade (Y0075 System Software Upgrade 06516). I have no clue what this is about.
Hopefully this information will help others with similar problems.

>>**Ref # 06516 "upgrade" - does anyone have any FACTS on WHY this reprogram ?? Lots of chatter on the SRX forum - specifically related to observed lower performance and perhaps due to clunking/ noises in the N*V8 AWD gear boxes and stress of same on WOT (not for me) starts, as well as a recent "safety recall". [Gear stress relief ??, smog/ emissions issue ??, safety ??, warranty ??]
I declined to let my service advisor "reflash" my 2005 SRX N*V8 RWD ( it was in the GM dealer's system for my VIN, but I have not been specifically notified by GM to have it done) at least until I hear some FACTS [none yet]. A slower throttle back-off in heavy/ freeway traffic makes me cautious, especially since the "original flash" is NOT RETRIEVABLE.
Otherwise, I love this car !!