Transmission has trouble shifting up. Possible slipping.

It sounds like you may be experiencing transmission issues with your 1995 Chevrolet 2500. Here are a few possible causes for the symptoms you described:

1. Low transmission fluid: Check the fluid level and condition of the transmission fluid. Low or dirty fluid can cause problems with shifting and may cause the transmission to slip.
2. Transmission filter: A clogged or dirty transmission filter can also cause issues with shifting and slipping. Replace the filter and see if that improves the situation.
3. Shift solenoid: The shift solenoid controls the flow of fluid to the transmission and can wear out or become damaged over time. If the solenoid is faulty, it can cause problems with shifting.
4. Valve body: The valve body is responsible for controlling the flow of fluid to the transmission and can also become worn or damaged. This can cause issues with shifting and slipping.

It is recommended to have a certified mechanic diagnose and repair the issue as transmission problems can be complex and require specialized tools and knowledge to fix.

check fluid level and condition ---have scanned for any trouble codes -----can be anything from tcm --to 4wd problems need to have diagnosed not just guess about a part

Automatic Transmission Slipping

www.aa1car.com/library/transmission_slipping.htm

Transmission slipping may be caused by several things: ... there must be enough fluid to generate the internal pressure required to engage the various gears.

Top 10 Signs of Transmission Trouble - HowStuffWorks

auto.howstuffworks.com/under-the.../5-signs-transmission-trouble.htm

It may happen when trying to get into first gear from a stop, or at any point up and down the assorted gears. Common causes include low transmission fluid, ...

10 Most Common Transmission Problems

www.transmissionrepaircostguide.com/10-common-transmission-proble...

A clunking sounds when you shift gears almost always lies within a .... If the transmission is spontaneously slipping in an out of gear (or simply popping into ...

Transmission Slipping - Transmission Repair Guy

get it fixed, are you going to diagnose and repair and A/T?
that car is a 1/2 GM/ Daewoo car. a sad mix of parts. (sell it? i would )
the service book is here. $4
This is called an FSM.
https://suzukipitstopplus.com/Products/1068-2007-forenza-reno-service-manual.aspx

783 (p07xx means tranny issues)

quote FSM:
Trouble Code: P0783 (2.0L L4 VIN - Auto)
3 - 4 Shift Malfunction Print this code data comments in (xxxx)
Trouble Code Conditions: (preconditions before test)
Transaxle oil temperature is greater than -10 °C (14 °F). Selector lever is not N (Neutral), P (Park) position. (warm , in gear)
System voltage is greater than 9 V.(car battery not dead)
No input speed error DTCs P0715, P0716 and P0717.
Speed sensors not dead.
Output speed is greater than 256 rpm. (tail shaft rpm (speed)
Input speed is greater than 400 rpm. (engine rpm after clutch)
3 - 4 gear shift is active. (the TCM commands shifts to 4th)
Possible Causes:

• Circuit to solenoids bad.
• ECM, bad.
• TCM bad or inputs wrong.
• end quote.

Comments:
this means, in pure physics.:
the transmission slip's
what that test failure means it bar stool talk is this.
I shafted to 4th but the MPH is too slow, so the transmission
is not shifting to 4th , or it slips

any mech would drive the car first. (did he?)
and flog it up hills (in Kansas? omg)
TO SEE, if it slips in 4th or fails to shift at all.

1. fresh ATF? and filter? serviced and levels good on A/T
2. is the 4th gear command to the shift solenoid good.?(logic)
3. if trans slips? (fails FSM book stall tests) bad tranny.
4. if the trans fails stall , check line pressure per FSM.

like that, and more, lots to say on A/T
If in uSA find a real , shop, with ASE techs. and win.

I would take it to a couple of different trans shops for advice.
Not really possible to "test" a transmission by driving it.
It has an over-ride safety to shift up even if the selector is in low.
My first guess would be the clutches are slipping or there is a solenoid that is not holding.
May be trouble codes in the computer.

P0732 FORD - Incorrect Second Gear Ratio
Transmission in second gear and the ECM detected an incorrect gear ration. This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by Transmission Control Module (TCM) as follows:

Torque converter slip ratio = A x C/B

A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from Engine Control Module (ECM)
C: Gear ratio determined as gear position which TCM supposes

If the actual gear position is higher than the position (2nd) supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction.

Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Incorrect transmission shifting

Possible causes
- Low transmission fluid level
- Dirty transmission fluid
- Shift solenoids
- Transmission mechanical problems
- Transmission hydraulic control circuit

Tech notes
Start by inspecting the transmission fluid level and condition, and change fluid if necessary.


Hope helps.

P0733 indicates which gear has a gear ratio that varies from the correct gear ratio, the corresponding in-gear trouble code ranges from DTCs P0731-36.

Without taking apart the transmission and inspecting for damage, it is difficult to say what the exact problem is, but many people who get the P0733 code have fixed the problem by replacing the accumulator in the transmission.

Other possible causes include:

• ATF level low
• Deteriorated ATF
• Shift solenoid B or F malfunction
• Pressure control solenoid malfunction
• Line pressure low
• Low clutch slipping
• High clutch slipping
• Control valve malfunction
• Oil pump malfunction
• TCM malfunction

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

P0733 indicates which gear has a gear ratio that varies from the correct gear ratio, the corresponding in-gear trouble code ranges from DTCs P0731-36.

Without taking apart the transmission and inspecting for damage, it is difficult to say what the exact problem is, but many people who get the P0733 code have fixed the problem by replacing the accumulator in the transmission.

Other possible causes include:

• ATF level low
• Deteriorated ATF
• Shift solenoid B or F malfunction
• Pressure control solenoid malfunction
• Line pressure low
• Low clutch slipping
• High clutch slipping
• Control valve malfunction
• Oil pump malfunction
• TCM malfunction

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

sounds like the clutches are slipping or you have a bad seal in tranny, which wont allow it to keep pressure. have you changed the fluid and filter?

do u have any transmission trouble codes? u should if the OD light is flashing, the light flashes to alert u that a electronic malfunction is occurring in the trans controls, u may just have a bad trans connector or a shift solenoid starting fail due to a shorted field closing coil.