2017 Tahoe LT not shifting into drive

rub_dirt_on_it said:

Level and color are all perfect with no burnt smells. I haven’t had it serviced that I can think of.

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> Engine light on/DTCs?

> Does it just move forward in manual low but not engage then upshift normally when you move it to Drive?

> Do you have a bi-directional scan tool that can monitor live data streams from the transmission to see what it's doing while vehicle is in operation?

> Any changes in the transmission's behavior since yesterday?

Based on your description in the first post, it sounds like you have a 'false neutral' condition in Drive which is almost always caused by a malfunctioning TEHCM (transmission electronic hydraulic control module). The same applied elements are at work in first gear when in Drive and Low so if you had a failure at either the low sprag or 1-2-3-4 clutch, you'd have no forward movement at all in Drive, Manual (if equipped) or Low.

No engine lights, and I am not sure what DTC stands for. I have zero error messages coming up on the dash.

In both low and drive, the car acts as if it is in neutral. It won’t go forward, and when I hit the gas pedal, it just revs the engine.

I don’t have any a scanner of any sort, but if you recommend I buy one, please share a link!

No other changes since yesterday.

I am getting it towed to a shop this morning. Fingers crossed they don’t have to replace the entire transmission.

rub_dirt_on_it said:

No engine lights, and I am not sure what DTC stands for. I have zero error messages coming up on the dash.

In both low and drive, the car acts as if it is in neutral. It won’t go forward, and when I hit the gas pedal, it just revs the engine.

I don’t have any a scanner of any sort, but if you recommend I buy one, please share a link!

No other changes since yesterday.

I am getting it towed to a shop this morning. Fingers crossed they don’t have to replace the entire transmission.

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If its not moving forward in either drive or man low then its likely your low sprag that has rolled over and failed. Also possibly 1-2-3-4 clutch piston cracked/broke catastrophically which would explain why it happend with no slippage in forward prior...Trans needs to come out for overhaul.

DTC = disgnostic trouble code.

I use a snap on Solus Ultra as well as a TECH2 for my older GM vehicles...

rub_dirt_on_it said:

No engine lights, and I am not sure what DTC stands for. I have zero error messages coming up on the dash.

In both low and drive, the car acts as if it is in neutral. It won’t go forward, and when I hit the gas pedal, it just revs the engine.

I don’t have any a scanner of any sort, but if you recommend I buy one, please share a link!

No other changes since yesterday.

I am getting it towed to a shop this morning. Fingers crossed they don’t have to replace the entire transmission.

Click to expand...

Have you had any luck with this my 2017 just started doing the exact same. Drives in reverse but nothing forward. No lights or codes. Fluid is good.

Jkmk said:

Have you had any luck with this my 2017 just started doing the exact same. Drives in reverse but nothing forward. No lights or codes. Fluid is good.

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Probably #1 checkball worn/stuck in the spacer plate. Could also be 1-2-3-4 broken piston (not as likely) or rear sprag but those dont fail too often.