SMK

Just to make certain that its in the transmission, and not the cable. I'd unhook the cable, and make sure its operating freely. Then try to manually operate the mechanism. Yeah, its probably internal. But sometimes you do get lucky.

If it goes easily into gear with the motor off. Then its likely something more than a simple fix. Sounds like something internal.
A bad clutch is certainly possible. But if it were the clutch, wouldn't it be difficult to get into any gear? If it were a car, I'd say that it sounded like a faulty synchronizer. Since you've said that it will go into gear while its not running. That would require opening the transmission. Also any internal transmission parts would likely be difficult to find. But certainly not impossible. 
You'll have to take out the transmission to replace the clutch. So I'd bet the problem will be easier to find then. There's not much to a manual transmission, it's certainly not as complicated as an automatic. I'd try to find a shop service manual, that pictures the assembly. I'd be willing to bet that if the transmission is removed, it would be much easier to find someone to take a look at it.

Sounds like a cable malfunction. Or possibly there's an obstruction. Maybe a small stick is wedged in there. It happens a lot with any off road vehicle. Usually its just wedged harmlessly though. But sometimes it'll bind up something important.
So you need to get underneath while someone tries to shift. Do NOT force it. Just gently back, and forth while you watch the linkage try to operate. See what moves, and follow the cables, or linkage. Check from the shifter, all the way to the transmission. It sounds like there's a couple of cables involved, since hardly anyone uses mechanical linkage anymore. Make sure you're following the proper cable. Its usually not hard to find the problem. Cables typically fail on the inside though. So keep that in mind. Cables cannot be repaired. They're cheap enough, so they just get replaced.
If its certain that there's no obstruction. And the cables are in good working order. The next step would likely be the transmission itself.

Thank you for the info. Idk if there’s anything stuck because when I’m in the car and it’s not on I can shift into all gears just fine.


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I’m not a mechanic so I don’t really know where to look for the problem and I can’t find a local shop or person to help diagnose the problem. I’m located in Southern California. So my Viper won’t shift into 3rd or 4th but 1st 2nd and reverse work fine. Can anyone point me in the right direction? Thanks

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