Automotive Forums  Where Car Enthusiasts Go to Discuss Cars Online

Ok. I have a 98 Oldsmobile Intrigue. The auto transmission has been rebuilt totally in 2004, its been about 30,000 miles since having a trans fluid flush. The car has been shifting/functioning perfectly ever since then until a couple weeks ago.  

The trans shifts in all gears fine, but the issue im having is while driving in 4th gear (cruising is just fine) but when accelerating a little (either passing or going up a hill) but not so much it down shifts into 3rd, the car jerks forward and backward vigorously at around 2000-2500rpms until you either take the foot off the gas, or push it until it down shifts. This seems to only happen in 4th gear.

The trans fluid is at normal level, but a little dirty. I've heard it most likely needs trans fluid change (which would be the cheapest fix). I've also heard that it could be some sort of converter used in 4th gear is not functioning correctly (sorry i don't know a ton about transmissions). I've heard it could be an injection problem, being that its not providing enough fuel needed to accelerate properly in 4th gear (but then wouldn't it happen in all gears?)

any info would be great.
thanks!  

these 4t65e transmissions are notorious for desplining the 4th clutch hub. try a free diagnostic at a local small business. then you will know thge best starting point.  
ASE/ATRA MASTERS REC/EXP, OEM, ATC AUTO DEGREE

oh man mine does the same thing just started doing it after I replaced my engine  

After replacing the engine.  My car started shifting a little early on all gears.  Then it developed a problem with the third gear being intermittent where it would try to catch but it would shake the car until I lifted my foot off the accelerator.   Just a few days ago it started skipping the third gear completely.   Mechanic replaced the filter kit and cleaned up some pipe but it did not solve the problem.  

Section: 07 - Transmission/Transaxle
Bulletin No.: 0O-07-30-002B
Date: July, 2002

Subject:
Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic
Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace
Pressure Control Solenoid Valve Assembly)

Models:
1997-1999 Buick Riviera
1997-2002 Buick Park Avenue
1998-2002 Buick LeSabre
1999-2002 Buick Regal
2000-2002 Buick Century
2002 Buick Rendezvous
1997-2001 Chevrolet Lumina
1997-2002 Chevrolet Monte Carlo
1999-2002 Chevrolet Venture
2000-2002 Chevrolet Impala
1997-1999 Oldsmobile Eighty Eight
1997-2002 Oldsmobile Silhouette
1998-2002 Oldsmobile Intrigue
2001-2002 Oldsmobile Aurora (3.5L)
1997-2002 Pontiac Bonneville, Grand Prix
1999-2002 Pontiac Transport/Montana
2001-2002 Pontiac Aztek
with Hydra-Matic 4T65-E (RPOs MN3, MN7, M15, M76)

Condition:
Some owners of the above vehicles with a HydraMatic 4T65-E transaxle
may comment on harsh upshifts or harsh garage shifts, soft shifts,
shudders on hard acceleration, or shifts erratic. These conditions may
appear intermittently or set a DTC P1811 or P0748. During diagnosis, a
low or high line pressure (actual versus desired) may be observed.

Cause:
The above condition may be due to any one of the following which may
affect line pressure output:

Sediment inside the pressure control (PC) solenoid valve, causing the
PC solenoid valve to mechanically bind.
Sediment in the valve body, causing the torque signal regulator valve
to stick.
Incorrect transaxle oil level  

i too have a 98 intrigue and have all the symptoms listed in that TSB. Trans feels fine when cold but after about 30 minutes of driving it starts to shudder/slip on takeoff, shudder between gears, shifting all-around feels weak unless I go easy on it (which is what I have been doing) but eventually it throws the p1811 code and goes into full line pressure/max adapt, getting rid of all my shuddering & slipping but has a very hard shift (obviously the PCS has been disabled when the p1811 code is set and shifts will be harsh until the code is cleared when the vehicle is turned off)  I find it odd that my transmission will slip in any high gears when warmed up (D,3,2) but will not slip AT ALL if i manually start off in 1st gear ...anyone have any idea how big of a job it is to do a pressure control solenoid in a 98 intrigue/4T65E trans? I heard it is a hard job to do in the montanna/venture due to the subframe removal (same trans., different vehicle)