Hey there Confuzzled

I doubt if your oil light issue has anything to do with your transmission problem. P0757 in an internal performance (Slipping Code) inside the transmission, during the 2-3 up-shift, and has nothing to do with the engine performance, or operations of the engine.
The computer monitors engine speed, input and output speeds at the transmission, TPS and engine coolant temp to control shifting. When the input and output speeds don't fall within a set parameter of programmed tolerances for each commanded gear, performance codes will set. Code P0757 will set for the 2-3 up-shift malfunction. The computer is commanding 3rd, but the gear ratio (input and output speeds) determined that it didn't make the shift.

If the vehicle free wheels above 30 mph, and higher rpms are needed to overcome the free wheeling. This condition may be caused by any of the following:

Chips or debris plugging the bleed orifice of the 2-3 shift solenoid. This will cause the transmission to stay in second gear when third gear is commanded and return to first gear when fourth gear is commanded. This can be confirmed by observing scanner data while driving the vehicle.

A 2-3 shift valve or 2-3 shuttle valve that is stuck, restricted and/or hung-up in its bore inside the valve body.

This condition may also be an indication of a damaged or slipping 2-4 band or 3-4 clutches. This clutch damage may also generate debris causing the 2-3 shift valve to stick in the valve body bore and set DTC P0757.

Inspect the condition of the transmission fluid for signs of overheat or a burnt odor. If either is noted, (as you said) the transmission should be disassembled for further investigation and repaired as needed.

I hope this information gives you a better understanding of the issue you are dealing with. If you have any other questions or concerns, please feel free to ask. We are all here to help, learn and understand. Please let us know what you decide to do.

Best of luck to you my Saturn Brother.

 

You are not alone in the P0700 P0757 code land.

Most of the info I posted I found by searching P0070 P0757 saturn as a single phrase. Especially the post about possible clutch and band issues., and what specifically sets the P0757 code.

I am completely confused about your oil light comment.
If you mean the oil light on the dash, it better NOT be on while driving, dim or otherwise. That light is for ENGINE oil pressure, not tranny fluid level. Nothing to do with tranny fluid level, pressure, ......

What is engine oil level?

Possible bad oil pressure sender, or failure to develop proper oil pressure which means internal engine damage is occurring.

Or the bulb is old and coated internally. Or got half knocked around and is loose in dash,

How bright is the oil light during key on bulb check without starting engine?

And that 13 quarts just in the tranny pan can't be right unless some moron found out it would sometimes shift if they over filled it some. SO they kept adding...and adding....

 

Hey Alpha -- great to see you!

Thanks for stopping by to help out with this one.

(Alpha is the pro I mentioned) -- professional transmission DUDE.

Alpha's word is based on years of professional personal experience.
I take his word as gospel.
Up to you as to how much faith you put in it.

--------

I would check out the oil light thing before you have someone rip into the tranny, since if the engine has internal damage from oil starvation, it may be more cost effective to junk this ride and begin anew.

Keep us updated

 

hello alpha...

no the engine is not junk, it was just put in... and please read this and tell me what you guys think...

https://www.yourmechanic.com/article...ressure-switch
this looks exactly like my switch i took out of old motor

and i agree derf.. i can find many post of codes but im talking about the combination of po700 and po757 together and only them that i find unique. and yes, someone didn't understand how to check that fluid, lol
also was my first sealed transmission so i did the research before i changed filter & fluid so i could make sure proper amount was in it.

 

Hey there Confuzzled

Yes, that switch looks similar to an engine oil pressure sending unit, sensor or a switch for the warning light. It actually does the exact same thing as an transmission pressure switch in some transmissions. It either turns on a warning light, or sends a signal back to the computer. Unfortunately the 4T45E has no external sensors except for the output speed sensor. My guess is that you pulled that sensor off the motor, not the transmission. I have provided a link showing what the electronic pressure control solenoid (EPC) #312 and the manifold pressure switch #13 look like. The manifold pressure switch tells the computer what range the transmission is in, like park, neutral or drive. The EPC solenoid varies pressure according to several factors like engine temp, and engine load for example, to control the quality of the shifts. Under heavy throttle it boosts line pressure for a harder shift. If either one of these sensors had a problem, you would have different codes, and different malfunctions, such as harsh engagement, and a flair on the 1-2 shift, or a really hard shift on the 1-2, before the code sets and the trans goes into limp-mode / fail-safe. Now I'm not saying you didn't replace the EPC solenoid when you had the side cover off the transmission to replace the shift solenoids...I'm saying it doesn't look like the sensor in the link you provided. That sensor has threads on the end, all the sensors on your transmission bolt in with a bracket.

GM's 4T45E Transmissions: The Good, Bad And The Ugly

There have been issues with the manifold pressure switch, but I have not seen one that just sets a code at 45 mph. At 45 mph, the computer should be commanding 4th gear. I would recommend taking this to a transmission shop, where they can drive the vehicle while observing the scanner data to watch command gears and ratios. Shift points under normal acceleration; 1-2 shift at 10 to 15 mph, 2-3 shift at 25 to 30 mph, 3-4 shift at 40 to 45 mph.

Most transmission shops like Cottman or Aamco will do a free road test and evaluation. Call around to make sure, and you will most likely need to leave the vehicle. If you wait, you may not get an accurate diagnosis because they are hurrying to get you an answer, instead of taking their time and researching the problem. I will tell you though, most shops won't try to patch a problem transmission with 100,000 miles, everything else is worn out inside it. Anything over 100K has reached it's life expectancy anyway, as far as American built transmissions go (Ford, GM, and Chrysler). That's why no one warranties transmissions for over 50K, way too many parts that wear out.

Now, about that oil light? When does it come on? I would guess at idle, sitting at a stop, after the engine warms up a little. This could be caused by a host of problems from a faulty sensor, too low of an idle at a stop, internal engine issues like a worn or damaged oil pump or sludge build up in the oil return passages. You were on the right path with replacing "all" the sensors off your old engine. Although it's the same engine size, you are using it in a different application, with different perimeters inside the computers. I would replace all the sensors, including the idle control solenoid and TPS if it has one. The MAP and or MAF, any EGR and EVAP sensors too that are attached to the old engine.

After that I would clear the KAM, (keep alive memory) using a scanner, and re-learn the idle control solenoid. At the very least, replacing the oil pressure sending unit would be a good place to start. There may be more that one. Some send a signal to the computer, some to a warning light. Do you have any other codes besides the p0700, which by the way, is just a code the TCM sends to the ECM to turn on the warning light, and to let you know there is a code stored in the TCM...code p0757. P0757 being a 2-3 shift performance code, could be mechanical or hydraulic, ie (clutches, bands and/or valve body) If it was electrical, it would set other codes.

Let me know when that oil pressure light comes on. And exactly what the trans does at 45mph, does it down shift, or free wheel like it's in neutral?

 

the light is just barely on like its being lit up by surrounding lights, its white light not red so might not mean anything... the only two codes im getting is po700 and po757. the suv runs great and shifts nice from first to second.then just high rpms at 45 and engine light comes on. if changing that pressure switch doesn't help im going to look at rebuilding or buying a re-manufactured one. just eliminating everything possible first. did u look at that link... and yes i did take it out of block... its located right above starter, but what i was thinking with electric trannys is it can take info from all sorts of places, like the oil switch on engine... been trying to find someone that knows if that particular tranny does???? and i was thinking the valve in valve body might be stuck.... when i drained fluid and dropped pan it was pretty damn clean... just brown fluid, not burnt, no metal... i changed solenoids in side cover, it all looked clean, just a few peices in fluid that looked like it was gelled but it was cold also.

 

critical for comparison to behavior of light with car running.

 

its red when u just turn key on, but after starting its faint white like its being lit by surrounding light

 

what im trying to find out is if that tranny gets info for shift from that oil switch or if it detects low pressure if it will put tranny in limp mode... any suggestions where to look???

 

Does the oil light intensity flicker with changing rpms? In Park?
Does the "vehicle running" appearance match the "car not running no key in it" appearance?
Does the intensity of the oil light change when the headlights are turned on and the dash is lit up?

I'm not trying to nitpick you to death, I'm trying to help you determine if the thing is really lit.

Typically the telltale/idiot lights are isolated from the dash light bulbs and also spaced from each other and masked between them so that light from other sources cannot enter the area that the actual bulb occupies.

I am pretty sure these lights are either on or off as they are triggered by a limiting lower pressure value stored in the PCM /BCM which, when reached, closes the ground on a 12V circuit which lights the bulb

But I am not POSITIVE.

I would have the oil pressure tested by a shop where they put a known good pressure sender in and measure it directly (not through the computer).
Even if you were to pull the dash to get to the instrument cluster, a faint glow still doesn't tell you if the pressure sender is good or not