2004 Park Avenue Ultra shifting hard after transmission fluid change

[killeraxemannic]

My PA was leaking transmission fluid from the pan seal so the fluid was changed with a drain and fill as well as a filter change. The fluid used was Valvoline MULTI-VEHICLE (ATF) Full Synthetic. The car started shifting hard when driven for longer distances like 20-30 miles. I put some Lubegard 60902 ATF Protectant in it and it seems like it shifts faster and smoother however it still ends up developing the hard shift if the car is driven for long enough. I'm wondering if the fluid used isn't the best option and if I should switch it out for something else. Even though the Multi Vehicle fluid says it's recommended for Dextron vi, iii, and ii I noticed there are some more Dextron specific fluids available.

 

[MelsRegal]

Did you check fluid level when hot?

 

[HotZ28]

How long & how many miles have you driven it after the fluid & filter change? Don't expect a miracle to happen during the first 1k.

 

[killeraxemannic]

Did you check fluid level when hot?

Yes it seems to be right up to the 2nd dot

How long & how many miles have you driven it after the fluid & filter change? Don't expect a miracle to happen during the first 1k.

It's been about 500 miles since the fluid change. Should just keep driving it as normal?

 

[HotZ28]

After the pan was dropped & the filter changed, how many quarts of fluid did you install?? It should hold about 7-Qts after that service.

 

[nunyabiz]

Transmissions are too complex and varied for one fluid to cover all. Change it to genuine Dextron.

 

[killeraxemannic]

After the pan was dropped & the filter changed, how many quarts of fluid did you install?? It should hold about 7-Qts after that service.

It took a little over 7 qts, it was drained overnight.

 

[imidazol97]

Is the fluid level check being done with the trans hot from driving 10 or more minutes and with the
engine idling and trans in park?

My first take on the hard shifting is that it's the code 4811 IIRC due to the modulator valve leaking
fluid past it from wear in the bore, so that it's not able to control the shift time on the activators that
do the shifting.

If it's that 4811 problem, my 03 would be fine if I shut it off and let it sit for at least a minute and then
restarted it. Evenutally the leaking would mean the fluid pressure wasn't right to control the shift times
and the trans control would go into default mode which gives a high pressure/rough shift. I could stop and turn off the
engine and then drive 70 miles home on the interstate and it wouldn't default until after driving through several
stops after getting off the interstate to reach home.

 

[HotZ28]

Triple Edge Performance

tripleedgeperformance.com

 

[02LTD]

Sounds like a classic P1811 code. A TransGo shift improvement kit may be in your immediate future. Get it scanned with a high level scanner to be sure.

 

[killeraxemannic]

Is the fluid level check being done with the trans hot from driving 10 or more minutes and with the
engine idling and trans in park?

My first take on the hard shifting is that it's the code 4811 IIRC due to the modulator valve leaking
fluid past it from wear in the bore, so that it's not able to control the shift time on the activators that
do the shifting.

If it's that 4811 problem, my 03 would be fine if I shut it off and let it sit for at least a minute and then
restarted it. Evenutally the leaking would mean the fluid pressure wasn't right to control the shift times
and the trans control would go into default mode which gives a high pressure/rough shift. I could stop and turn off the
engine and then drive 70 miles home on the interstate and it wouldn't default until after driving through several
stops after getting off the interstate to reach home.

This is exactly what It's doing right now. It runs great on the highway but as soon as you hit some stop and go traffic it starts to do the hard shift. It goes away if you turn off the car for a minute or two.

 

[HotZ28]

This is exactly what It's doing right now. It runs great on the highway but as soon as you hit some stop and go traffic it starts to do the hard shift. It goes away if you turn off the car for a minute or two.

Did you read the link in post #9??

 

[killeraxemannic]

Did you read the link in post #9??

Just saw it. Been reading similar info to what's in that post as well various places online. I'm kinda hoping that it might get better after this fluid wears in a bit. The car wasn't doing anything weird before the fluid was changed so I'm leaning more towards it just being a friction issue instead of a bad solenoid or other bad parts. I just got back from a 600 mile road trip going over a few mountain passes in Colorado. The transmission preforms perfectly except for the 1st to 2nd shift. It upshifts and downshifts fine on the highway and even going up a mountain pass. The only time on the whole trip that the car went into the hard shift mode was when I caught some stop and go traffic.

 

[HotZ28]

Just saw it. Been reading similar info to what's in that post as well various places online. I'm kinda hoping that it might get better after this fluid wears in a bit. The car wasn't doing anything weird before the fluid was changed so I'm leaning more towards it just being a friction issue instead of a bad solenoid or other bad parts. I just got back from a 600 mile road trip going over a few mountain passes in Colorado. The transmission preforms perfectly except for the 1st to 2nd shift. It upshifts and downshifts fine on the highway and even going up a mountain pass. The only time on the whole trip that the car went into the hard shift mode was when I caught some stop and go traffic.

Considering where you are driving, you may also want to install a trans cooler, if not not originally equipped with one. Get a trans code scan, to see what the problem is.

 

[HotZ28]

I should also mention, there is no such thing as "4811" trans code! New fluid has more detergents & can cause temporary harsh shifts, until after the clutches soften somewhat. You will be safe to keep driving it while the new fluid does it job!

 

[Pirate Pete]

Considering where you are driving, you may also want to install a trans cooler, if not not originally equipped with one. Get a trans code scan, to see what the problem is.

How do we know if our PA has a trans cooler pre-installed? In in the Mojave desert and it gets hot as a mofo here in summer 🔥🔥🔥

 

[HotZ28]

How do we know if our PA has a trans cooler pre-installed? In in the Mojave desert and it gets hot as a mofo here in summer 🔥🔥🔥

The PA Ultra, came equipped with a trans cooler in front of the A/C condenser, but did not have a fan in front of the cooler to help cool the fluid in extreme temps when not driving above 30-mph. You apparently have a base PA & it would not have that cooler unless you install that yourself. I have a winter home in Lake Havasu, south of LV & can get even hotter there. I installed a trans cooler with a fan blowing through the cooler & never had a problem.

 

[Pirate Pete]

The PA Ultra, came equipped with a trans cooler in front of the A/C condenser, but did not have a fan in front of the cooler to help cool the fluid in extreme temps when not driving above 30-mph. You apparently have a base PA & it would not have that cooler unless you install that yourself. I have a winter home in Lake Havasu, south of LV & can get even hotter there. I installed a trans cooler with a fan blowing through the cooler & never had a problem.

Ive had to ad trans fluid once or twice in the summer and don't have any leaks . Wonder if it's from getting too hot ? 🤔

 

[HotZ28]

Have you checked the fluid temps using an IFR sensor on the lines, both supply & return?

 

[G-430316]

This is exactly what It's doing right now. It runs great on the highway but as soon as you hit some stop and go traffic it starts to do the hard shift. It goes away if you turn off the car for a minute or two.

Mine was doing the same thing fine at cool temperature but after being on the highway and up to temperature then hitting stop and go traffic it would slam into each gear violently like the worst shift kit ever. I took it to a highly recommended and qualified transmission shop they said no fluid in the world would make it better. That there's a rod in the valve body that's not moving causing the pressure to become too high. The car had 140,000 miles on it and the fluid had always been changed at oil changes like just what was in the pan just to keep it fresh. And the fluid was always nice and red with no signs of degradation. The transmission was rebuilt and 5,000 miles later still shifting like new...it's funny how car's seem to do the same thing's...I wouldn't beat myself up over the fluid change manufacturer it was probably just coincidence cos I used the recommended fluid religiously...