: Hard Shifting Transmision



Back Door Man
10-24-03, 11:42 AM
I have a 02 Deville with 46000 miles. When the car is cold the trans. shifts realy hard when going from park to reverse and from neutral to drive. I have had it in the shop 3 times so far with the following results. 1. They looked at the motor mounts and couldn't find a problem, but when the trans. man saw and heard what was happening the responce was "the valve body is bad". Reschedule another shop call. In shop for 2 weeks!
2. They found this time that the moter mounts needed to be replaced. They replace the mounts and when I picked up my baby it still shifted hard. In shop this time for 3 weeks!
3. Went back to shop again. I recived a call from them and said that the car has Calf. emmisions on it and that until the car warms up the trans will shift hard. I don't belive this!!!!!
It does not matter what the RPM is when the motor is cold (not up to operating temp) the trans. shifts hard.
Is this something that I will need to live with or are they feeding me a line???
If any of you could give me any information about this I would appreciate it.
Thanks Back Door Man

foo
10-24-03, 02:03 PM
I have a 02 Deville with 46000 miles. When the car is cold the trans. shifts realy hard when going from park to reverse and from neutral to drive. I have had it in the shop 3 times so far with the following results. 1. They looked at the motor mounts and couldn't find a problem, but when the trans. man saw and heard what was happening the responce was "the valve body is bad". Reschedule another shop call. In shop for 2 weeks!
2. They found this time that the moter mounts needed to be replaced. They replace the mounts and when I picked up my baby it still shifted hard. In shop this time for 3 weeks!
3. Went back to shop again. I recived a call from them and said that the car has Calf. emmisions on it and that until the car warms up the trans will shift hard. I don't belive this!!!!!
It does not matter what the RPM is when the motor is cold (not up to operating temp) the trans. shifts hard.
Is this something that I will need to live with or are they feeding me a line???
If any of you could give me any information about this I would appreciate it.
Thanks Back Door Man



Umm.. what EXACTLY do you mean by shifting hard?
Is it like, you are in park and you put it in reverse and it tries to lurch the car backwards?

Back Door Man
10-24-03, 02:47 PM
Umm.. what EXACTLY do you mean by shifting hard?
Is it like, you are in park and you put it in reverse and it tries to lurch the car backwards?
When I'm in park and the shift to reverse the trans. bangs real hard. It shakes the whole car and I suspect that is what tore out the motor mounts. I have not noticed a lurch but I always have the brake pedel depressed. The same responce happens when going from neutral to drive. The is no lurch, just a hard bang. This will happen until the temp. gauge is showing at least 3 bars.
I hope this answers your question.
Thanks
Back Door Man
02 Deville

Dubya
10-24-03, 03:26 PM
my 95 shutters and kicks about 1 in 25 times when going from park to reverse, been doing it since ive had it for 18 months, heard alot of people say this....its a aurora, but still has the same 4t80e trans

at least its under warranty for you

foo
10-24-03, 04:57 PM
if your car has a tach so you can see the RPMS of the engine.. tell me what the rpms say when you are in park and you switch it to reverse.. it should NOT lurch unless the rpms are high (above 1000) unless something is wrong with the torque converter... you will almost always feel a bump but nothing major like you are describing. Check the atf level also. I doubt it's anything to worry about though as long as the car drives ok

Back Door Man
10-24-03, 05:18 PM
foo
The RPM range varies from 675 to 1200.
But the rentals an 02, 03 & now an 04 Deville that I have had while mine is in the shop do not shift like this. Even at 1200 rpm they go from park to reverse without the bang.
Yes it is covered by the warranty but the dealer is giving me the run around about fixing it.
Thanks
Back Door Man
02 Deville

elwesso
10-24-03, 07:24 PM
Shifting hard is ALWAYS better than slipping......

Trannys are DESIGNED to shift hard when cold.....

epanightmare
10-24-03, 08:39 PM
Shifting hard is ALWAYS better than slipping......

Trannys are DESIGNED to shift hard when cold.....

Dose the speedometer work.
is there a service vehicle soon light or a check engine on.
Dose this happen even when the car is warm.
the harsh shifting condition that you are discribing could be caused by a faulty vehicle speed (VSS) sensor or a trans input shaft speed sensor (SSS). the pcm compares the output signal of these two sensor to determin if the transmission is slipping, and that it is in the same gear that PCM is commanding. If one of these sensor fails, then the PCM dissables what Cadillac calls garage shift. when garage shift is active the pcm lowers the line pressure in the transmission to give a nice soft shift from park or neutral to drive or reverse. Although now that i look at alldata i think that it is probably a faulty transmission fluid pressure (TFP) valve position switch
Also look for a techncial service bulletin number 01-07-30-009b as this deals with some of your problems

let me know what you find out

Back Door Man
11-14-03, 04:27 PM
Got the car back from the shop after 2 weeks. They replaced the PCM. But the hard (harsh) shift still happens. This happens only when the engin is cold. It will go away when the third tewmp. indicator light is on. I realize that a good tight shift with a automatic is better than slipping, but this is a very violent shift. The whole car shakes when it happens. How do you find out information that is on a TSB?
I have went to http://service.gm.com/gmtechlink/images/issues/cnt_mo/TLcme.html and found some good information about the garage shift problems. I am going to schedule another trip to the shop real soon. This will be about 5th time for the same problem. I wonder if maybe I should go up the feed chain in the cadillac family and start to bite some butt.

Thanks
Back Door Man
02 Deville

elwesso
11-14-03, 04:38 PM
Something is obviously amiss....... If you have another caddy dealer nearby, id take it to them and see if they can come up with something different!

Allante North *
11-14-03, 06:32 PM
Good advice Wes. I agree that you should consult another Cadilac Dealer. Your dealer may just be tired of fooling with a customer that has "Issues" and not really looking for a solution to your problem. Couldn't hurt to get a second opinion and just maybe a mechanic that has experience with this type of problem.

Good Luck and keep us informed.

SLS97
11-14-03, 08:39 PM
If the engine is cold it will have a higher rpm till it is warmed up. It sounds like there is play in the system and because the rpms are higher you are hearing the "play' being taken up and the system coming to a still. I remember when a universal joint would be bad you'd get this type of noise from the drive shaft.

myfleadeal
03-27-06, 06:58 AM
I have a 02 Deville with 46000 miles. When the car is cold the trans. shifts realy hard when going from park to reverse and from neutral to drive. I have had it in the shop 3 times so far with the following results. 1. They looked at the motor mounts and couldn't find a problem, but when the trans. man saw and heard what was happening the responce was "the valve body is bad". Reschedule another shop call. In shop for 2 weeks!
2. They found this time that the moter mounts needed to be replaced. They replace the mounts and when I picked up my baby it still shifted hard. In shop this time for 3 weeks!
3. Went back to shop again. I recived a call from them and said that the car has Calf. emmisions on it and that until the car warms up the trans will shift hard. I don't belive this!!!!!
It does not matter what the RPM is when the motor is cold (not up to operating temp) the trans. shifts hard.
Is this something that I will need to live with or are they feeding me a line???
If any of you could give me any information about this I would appreciate it.
Thanks Back Door Man I HAVE THE EXACT SAME PROBLE ON MY 2000 BUICK.

myfleadeal
03-27-06, 07:01 AM
They told me it was the "valve body". Two different trans. shops said it wasn't and there was nothing wrong with the transmission. I've already replaced a bad trans. mount. The jerking is what caused it to go bad. It only happens when the engine is cold. The RPM's are running to high (1500) and this is only the case when the engine is cold. No problems after the engine has warmed up. I've dumped about $600 thus far into the car with diagnostics, replacing parts etc........I am at my witts end. Anything would be helpful at this point.

eurumbaev
03-27-06, 11:29 AM
Do you get a Service Engine soon light when the car is cold? Have you checked your codes. If you have a PC0717 Code for an input speed sensor, this will cause your transmission to jerk the way you discribe. If you do, do a search for input speed sensor and you'll get plenty of info.

parts68
03-27-06, 07:58 PM
Im thinking its the PCS and or PCM controls of that solenoid.
Have them check the amp values in conjunction with a good pressure gauge.
4t80E specs are 300psi .02 amp draw,100psi .90 amp in reverse.
In drive,park,neutral 200psi..035 amps,50psi,1.00 amps.
This can be scanned while driving.
Also PCS value at the PCM will be 4.6 ohm.
I just fixed one of my auroras that did same thing.
Olds dealer and 3 tranny guys said it needed a new trans.
My diagnosis was the PCM,replaced that and all is well.
Also ask them to compare commanded amps verses the actual amps.

SL1CK
03-27-06, 08:07 PM
The question here is, have you checked for codes?

GreenMachine
03-28-06, 05:51 AM
are you on an incline at all?

Even if your not the next time park you car over night try setting the parking brake. Make sure you do before you take your foot off the brake pedal so the car doesn't "roll" or rest on the transmission. (bascially with your foot on the brake, put it in park, with your foot still on the brake, set the parking brake).

When you go to shift it out of park into reverse or drive, wiat a second for the parking break to release (should do it automatically when you shift).

Hope this helps.

myfleadeal
03-30-06, 06:10 AM
Do you get a Service Engine soon light when the car is cold? Have you checked your codes. If you have a PC0717 Code for an input speed sensor, this will cause your transmission to jerk the way you discribe. If you do, do a search for input speed sensor and you'll get plenty of info.

Unfortunately, there isn't any codes. Never had the service engine light come on either.

myfleadeal
03-30-06, 06:12 AM
Do you get a Service Engine soon light when the car is cold? Have you checked your codes. If you have a PC0717 Code for an input speed sensor, this will cause your transmission to jerk the way you discribe. If you do, do a search for input speed sensor and you'll get plenty of info.

Unfortunately, no codes. The service engine light has never come on either.

myfleadeal
03-30-06, 06:17 AM
I was told that the pressure control selenoid testing fine. I am curious though about the PCM. I am suppose to take the vehicle to a mechanic early next week. I do not believe now that it is a transmission problem but more of an engine problem. Something is driving the RPM's so high, question is.....what? I will ask them about the PCM. How do you know it is bad?

parts68
03-30-06, 07:52 PM
I was lucky and have 2 identical cars to swap PCMs on.
The one had a hard shift problem,even replaced motor mounts
to cure but still shifted harsh.
I put my snap on scanner on it and found the desired pressure and actual
pressure were different so swapped PCm and trans shifts fine.
PCm that was swapped caused the other car to shift harsh,which was fine before.
For high RPMs you may have to do a TPS/ISC relearn.