This is likely an issue with either the clutch master cylinder (CMC) or the clutch slave cylinder (CSC) on the transmission. I need you to try something. When it happens, turn the engine off and see if you can easily shift into first or reverse. If you can, we need to do some inspecting.
First, the CMC receives fluid from the brake master cylinder reservoir. See pic 1 below. So, make sure the brake fluid is full.
If it is full, then we need to check for leaks. The CMC is mounted on the firewall below and to the right of the brake master cylinder. If you follow the hose I circled on pic 1, it will lead you to the CMC.
Once you locate the CMC, check for leaks or any indication of damage. Also, under the dash in the vehicle, you will see a pushrod between the clutch pedal and the CMC. Check where it goes through the firewall and make sure nothing is wet.
If that checks good, then we need to check the clutch slave cylinder (CSC). The CSC is what receives pressure when you depress the clutch which in turn presses on a release bearing in the clutch housing. What I think is happening is either you will find a leak at the CSC or the CMC is starting to fail. However, that is based on being able to shift easily when the engine is turned off.
If you look at pic 2 below, it shows the CSC mounted on the transmission bell housing. I circled it. There will be a steel hydraulic hose going to it from the CMC.
Let me know what you find or if you have other questions. Also, sorry about all the CMC, CSC and so on. LOL
Also, keep in mind that if there is a problem with the transmission, the warranty is for 10 years or 100K miles. So, you should be covered.
See pics below.
Images (Click to enlarge)
Sunday, June 6th, 2021 AT 8:21 PM