Shifting Problems The van does not shift. Stays in low gear.

There could be a number of possible reasons why your G30 Chevy van is not shifting out of 1st gear. Some potential causes could include:

1. Faulty shift solenoids: The shift solenoids are responsible for controlling the flow of transmission fluid through the valve body, which in turn affects the shifting of gears. If the solenoids are not functioning properly, it can cause the transmission to get stuck in 1st gear.
2. Low transmission fluid pressure: If the fluid pressure in the transmission is too low, it can prevent the gears from shifting properly.
3. Faulty transmission control module: The transmission control module (TCM) is responsible for controlling the shifting of gears in an automatic transmission. If the TCM is faulty or has malfunctioned, it can cause the transmission to get stuck in 1st gear.
4. Internal transmission issues: There could be internal issues within the transmission itself that are preventing it from shifting out of 1st gear. This could include worn gears or clutches, or other mechanical issues.

It is recommended to take your van to a qualified mechanic or transmission specialist to diagnose the issue and perform any necessary repairs.

If your 2009 Mercedes-Benz MP3 model truck's gear is not working in automatic mode and only working in manual mode, there could be a few potential causes. Here are a few steps you can try to troubleshoot and solve the issue:

1. Check the transmission fluid level: Make sure that the transmission fluid level is at the correct level and is not low. Low transmission fluid level can cause gear shifting problems.
2. Check the transmission filter: The transmission filter may be clogged, preventing the gears from shifting properly. Replace the filter if necessary.
3. Check the transmission control module (TCM): The TCM is responsible for controlling the automatic gear shifting. If it's malfunctioning, it can cause gear shifting problems.
4. Check the gear selector switch: The gear selector switch may be malfunctioning and preventing the gears from shifting properly.
5. Check the solenoids: The solenoids in the transmission may be malfunctioning and preventing the gears from shifting properly.
6. Check the transmission control linkages: The transmission control linkages may be damaged or disconnected, preventing the gears from shifting properly.

If you are not comfortable with checking these things, it's best to take the vehicle to a certified Mercedes-Benz mechanic to diagnose the problem. The technician will be able to identify the problem and repair it as necessary.
It's important to note that some of these steps may require special tools and knowledge of the vehicle's transmission system, so it's best to take it to a professional mechanic to avoid causing more damage.

There could be several issues that could cause your GMC Envoy's transmission to not shift gears properly and the RPMs to rev high. Here are a few potential problems that you may want to consider:

1. Low transmission fluid: If the transmission fluid is low, it could cause problems with the shifting mechanism. You'll want to check the transmission fluid level and add more if needed.
2. Faulty shift solenoid: The shift solenoid is responsible for directing transmission fluid to the appropriate gear. If the solenoid is faulty, it could cause shifting problems.
3. Worn transmission bands or gears: If the transmission bands or gears are worn, it could cause the transmission to not shift properly and the RPMs to rev high.
4. Clogged transmission filter: A clogged transmission filter can restrict the flow of transmission fluid, causing shifting issues.
5. Faulty transmission control module (TCM): The TCM is responsible for controlling the transmission. If it's not functioning properly, it could cause shifting problems.

I would recommend having a mechanic diagnose and fix the problem for you. It's important to address transmission issues promptly, as they can lead to further damage if left unchecked.

Down shift manually should over ride any electronic controls. Two possibilities I see. Could be the valve body was tightened enough, blow by, You did have a sensor replaced in the transmission(OD). The other is the range selector switch on or in the transmission is bad. This switch/sensor tells the ECU what gear you want it to be in. Just a note. Depend on years. The throttle body and transmission have to go threw a relearn procedure when replacing parts. Takes a scanner to do this.

• A/T or M/T (auto or stick, gee)
• if A/T is this the 42RE box>? are you in DRIVE? or 1 or 2 gear.
• does rpm rise above 3000 rpm > at your attempt? if not ,its a bad engine (weak)
• is the shift linkage even shifting correctly (movement top and bottom)
• check levels yet. (and for pink ./red AFT not black-metal flake
• change the filter yet? or skip service. at 50k miles. ?????
• check all fuses yet>?
• using a basic OBD2 scan tool are there any tranny DTC errors?>
• does the FSM stall test pass? in 1st.? and reverse?
• if stall fails, slips , then tranny bad. if not its really stuck in 1st gear.

The TCM commads the gear change, there is no valve body brain.
the TCM shifts to second with good inputs to the TCM
if the TCM sees bad inputs it will tell you, SCAN IT.

try a new speedo drive sennsor on the gearbox

Time to take the truck to a transmission shop and get an estimate.

your trans is not shifting into over drive or your loclup is not working, try pulling codes from it or take it to a trans shop for a diagnostic, may get expensive good luck

checked fluid level? sounds slippy so check that.. and check that your shifter is all secure and nothings broken dude... probably low on fluids.
Derek

take it back to the shop that rebuilt it and tell them to readjust the throttle pressure cable. if its shifting early then you will damage the transmission from having to low pressure