Transmission Problems with my "new" Magnum!

[imperigal]

Normally, I don't buy cars from dealerships because I have the belief that they'll cobble things together just well enough to fool the un-knowing buyer, only to have the problem reappear once the "as-is" sale is complete. I'm not saying 100% that that's what happened to me, but I sure as heck was dissappointed with how much the dealer (Texas Direct Auto in TX) misrepresented the fact that there was OBVIOUS paint work done to the car. I had already purchased the car and still wanted it cause it was at a good price, so there was not too much I could do about it. The car ran and drove well and I've heard nothing bad about the engine/tranny combo in the Magnums/300s, etc.

I left TX last Friday and made it back to Michigan by Sunday afternoon. No problems. However, I noticed a slight "fluttering" in the trans when shifting from reverse into drive on Tuesday. Then on Wednesday I noticed a few more funny shifts.... nothing too bad, but my ears perked up. On Thursday... that's a different story. I was driving up Gratiot to work and when shifting from 2nd into 3rd it made a bad noise (heard and felt it). I could NOT get it to produce the sound again! So now, I am watching/feeling it like a hawk and notice that it shifts into 2nd much fast than it should (which it wasn't doing before). I thought perhaps "limp-in" mode, but that wouldn't make sense.

Any ideas???? Besides fluid, what else can I check? No leaks anywhere, level looks good. Any help would be appreciated greatly!!

Christine
2008 Magnum R/T (silver with all the options and Road & Track pkg)
1970 Plymouth Sport Fury
(yes, I actually work on cars, actively pursue old Mopars and have a respectable tool collection)

[NC-SXT]

When you say the level is good, how did you check it? These dont have transmission sticks. How many miles since a trans flush?

[imperigal]

Ok - more accurately - dealer said level was checked and good. So, I should probably not assume that it's true! I don't know if it's ever had a trans flush. Could it be something as simple as that? How would I check thie fluid level? Would it be something similar to checking the fluid in a transfer case?

[Popeye's Hemi]

Ok - more accurately - dealer said level was checked and good. So, I should probably not assume that it's true! I don't know if it's ever had a trans flush. Could it be something as simple as that? How would I check thie fluid level? Would it be something similar to checking the fluid in a transfer case?

If you query this forum you will find the fluid level charts and the dipstick is a Miller tool 9336 at about $70 or make your own using one from a Ram truck that is around 46" in length. Only about 39" is really needed. Mark the end at 10mm increments up to 70mm.
Then use the fill level chart to get the right level. The chart is based on temp of the trans fluid. If you have about 55mm to 65mm of fluid and the engine is at operating temp you should be good or at least close, but if you have more or less than I would get it corrected.

Here is most of the service TSB but the images will not copy over. Remember the chart has been posted here somewhere just need to look for it.

FLUID AND FILTER
DESCRIPTION
The oil level control is located on the electrohydraulic
unit (4) and consists of the float (5) which is integrated
into the electrohydraulic unit. The float is positioned to
plug the opening (6) between the oil gallery (2) and
gearset chamber (1) so that the rotating gearsets do
not splash about in oil as the oil level rises. The oil
level control reduces power loss and prevents oil from
being thrown out of the transmission housing at high
oil temperatures.
OPERATION
With low oil levels, the lubricating oil which flows constantly
out of the gearset, flows back to oil gallery (2)
though the opening (6). If the oil level rises, the oil
presses the float (5) against the housing opening (6).
The float (5) therefore separates the oil gallery (2)
from the gearset chamber (1). The lubricating oil which
continues to flow out of the gearsets is thrown against
the housing wall, incorporated by the rotating parts
and flows back into the oil gallery (2) through the
upper opening (arrow).
LX AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 379
DIAGNOSIS AND TESTING
EFFECTS OF INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air along with the fluid. Air in the fluid will cause fluid pressures to be
low and develop slower than normal. If the transmission is overfilled, the gears churn the fluid into foam. This aerates
the fluid and causing the same conditions occurring with a low level. In either case, air bubbles cause fluid
overheating, oxidation, and varnish buildup which interferes with valve and clutch operation. Foaming also causes
fluid expansion which can result in fluid overflow from the transmission vent or fill tube. Fluid overflow can easily be
mistaken for a leak if inspection is not careful.
CAUSES OF BURNT FLUID
Burnt, discolored fluid is a result of overheating which has three primary causes.
1. Internal clutch slippage, usually caused by low line pressure, inadequate clutch apply pressure, or clutch seal
failure.
2. A result of restricted fluid flow through the main and/or auxiliary cooler. This condition is usually the result of
a faulty or improperly installed drainback valve, a damaged oil cooler, or severe restrictions in the coolers and
lines caused by debris or kinked lines.
3. Heavy duty operation with a vehicle not properly equipped for this type of operation. Trailer towing or similar
high load operation will overheat the transmission fluid if the vehicle is improperly equipped. Such vehicles should
have an auxiliary transmission fluid cooler, a heavy duty cooling system, and the engine/axle ratio combination
needed to handle heavy loads.
FLUID CONTAMINATION
Transmission fluid contamination is generally a result of:
• adding incorrect fluid
• failure to clean dipstick and fill tube when checking level
• engine coolant entering the fluid
• internal failure that generates debris
• overheat that generates sludge (fluid breakdown)
• failure to replace contaminated converter after repair
The use of non-recommended fluids can result in transmission failure. The usual results are erratic shifts, slippage,
abnormal wear and eventual failure due to fluid breakdown and sludge formation. Avoid this condition by using recommended
fluids only.
The dipstick cap and fill tube should be wiped clean before checking fluid level. Dirt, grease and other foreign material
on the cap and tube could fall into the tube if not removed beforehand. Take the time to wipe the cap and tube
clean before withdrawing the dipstick.
Engine coolant in the transmission fluid is generally caused by a cooler malfunction. The only remedy is to replace
the radiator as the cooler in the radiator is not a serviceable part. If coolant has circulated through the transmission,
an overhaul is necessary.
The torque converter should be replaced whenever a failure generates sludge and debris. This is necessary
because normal converter flushing procedures will not remove all contaminants.
STANDARD PROCEDURE
CHECK OIL LEVEL
1. Verify that the vehicle is parked on a level surface.
2. Remove the dipstick tube cap.
WARNING: Risk of accident from vehicle starting off by itself when engine running. Risk of injury from contusions
and burns if you insert your hands into the engine when it is started or when it is running. Secure
vehicle to prevent it from moving off by itself. Wear properly fastened and close-fitting work clothes. Do not
touch hot or rotating parts.
3. Actuate the service brake. Start engine and let it run at idle speed in selector lever position P.
21 - 380 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION LX
4. Shift through the transmission modes several times with the vehicle stationary and the engine idling
5. Warm up the transmission, wait at least 2 minutes and check the oil level with the engine running. Push the Oil
Dipstick 9336 into transmission fill tube until the dipstick tip contacts the oil pan and pull out again, read off oil
level, repeat if necessary.
NOTE: The dipstick will protrude from the fill tube when installed.
6. Check transmission oil temperature using the appropriate scan tool.
NOTE: The true transmission oil temperature can only be read by a scan tool in REVERSE or any forward
gear position. (Refer to 21 - AUTOMATIC TRANSMISSION- NAG1/TRANSMISSION TEMPERATURE SENSOR/
PARK-NEUTRAL SWITCH - OPERATION)
7. The transmission Oil Dipstick 9336 has indicator marks every 10mm. Determine the height of the oil level on the
dipstick and using the height, the transmission temperature, and the Transmission Fluid Graph, determine if the
transmission oil level is correct.
8. Add or remove oil as necessary and recheck the oil level.
9. Once the oil level is correct, install the dipstick tube cap.
TRANSMISSION FILL
To avoid overfilling transmission after a fluid change or overhaul, perform the following procedure:
1. Verify that the vehicle is parked on a level surface.
2. Remove the dipstick tube cap.
3. Add following initial quantity of Mopar ATF +4, Automatic Transmission Fluid, to the transmission:
a. If only fluid and filter were changed, add 7.0 L (7.4 qts.) of transmission fluid to transmission.
NAG1 Transmission Fill Graph
LX AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 381
b. If the transmission was completely overhauled or the torque converter was replaced or drained, add 8.1 L
(17.1 pts.) of transmission fluid to transmission.
4. Check the transmission fluid (Refer to 21 - TRANSMISSION/AUTOMATIC - NAG1/FLUID AND FILTER - STANDARD
PROCEDURE - CHECK OIL LEVEL) and adjust as required.
FLUID/FILTER SERVICE
1. Run the engine until the transmission oil reaches
operating temperature.
2. Raise and support vehicle.
3. Remove the bolts (5) and retainers (4) holding the
oil pan to the transmission.
4. Remove the transmission oil pan (3) and gasket (2)
from the transmission.
5. Remove the transmission oil filter (1) and o-ring
from the electrohydraulic control unit.
6. Clean the inside of the oil pan (3) of any debris.
Inspect the oil pan gasket (2) and replace if necessary.
7. Install a new oil filter (1) and o-ring into the electrohydraulic
control unit.
8. Install the oil pan (3) and gasket (2) onto the transmission.
9. Install the oil pan bolts (5) and retainers (4). Torque
the bolts to 8 N·m (70 in.lbs.).
10. Lower the vehicle and add (4.0 qts.) of
transmission fluid to the transmission.
11. Check the oil level (Refer to 21 - TRANSMISSION/
AUTOMATIC - NAG1/FLUID AND FILTER - STANDARD PROCEDURE - CHECK OIL LEVEL).
Fluid/Filter Service Points
1 - OIL FILTER
2 - OIL PAN GASKET
3 - OIL PAN
4 - RETAINER
5 - BOLT
21 - 382 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION LX

[Shelby]

A 2008 should not have issues- it is relatively new and should be low miles. It should be under warranty.
2005 vehicles had the leaking seal on the dipstick tube- that led to water from the A/C in the transmission. This should not be an issue on a 2008.

It does not sound right.