New gear shift lever fitted, now cant get it out of low box when low gear is engaged without turning off the engine, grates loudly.

Try starting it in gear than shift with rpm dwn shift Rev rpm up by 1500 to up shif let rpm go down by 1500

thee are gear cable adjustment that ensure complete engagement of the drive dog in the leg
If it properly adjusted then you will have to pull te leg off and dissemble the gear box and fit new gears and a dog clutch
because it is a straight engagement into square segments and the engine shaft is running it hits and misses until it eventually engages
over time instead of square segments they become tapered and so will slip back out of gear under load
the operator will normally be at fault as the engagement should be at low idle with a sharp movement of the selector lever

are you saying this car is a A/T car, AUTO and not a stick?

say so, as both have 2,4 and reverse gears.

i think its a 5speed manual.

so the tip of the shifter is bad, remove it see plastic parts bad.

you could shift car , by moving the transmission levers and id bet it does work so that leaves. bad shift lever parts.

i bet the lever is real loose , so loose the H pattern is garbage
right> ?

Hi assuming you put the clutch back togethere in correct order you remove it does the clutch lever have end play in it when you releace it there should be some play in it if there is not you need to loosen it ether at the lever holder or at the set screw where the cable on the engine case lossen it then turn it until it lighly stops then back it off quarter of a turn.

In the front of it there is a gear box look and see if the oil is ok

This is a situation of low pressure,as you warm up the vehicle the transmission fluid is warmer which allow the torque convertor to produce pressure to collapse the clutch pack and transfer power for a shift gear,your solution is a torque convertor and a front pump

1. • 1 Start your Dodge truck's engine.
     
   • 2 Turn the electronic transfer case from "2WD" to "4WD Lock" to engage the high range 4WD, if the dodge truck is equipped with an electronic transfer case; otherwise, shift the transfer case lever from "2H" to "4H." The electronic transfer case is located on the instrument panel and is marked with "2WD," "4WD Lock" and 4WD Low." The lever-equipped transfer case is located to the right of your leg and is marked with "2H," "4H" and "4L."
     
   • 3 Shift the transmission into "Neutral" while the vehicle is either stopped or rolling at 2 to 3 mph to begin engaging in the low range 4WD. Turn the electronic transfer case to "4WD Low," if the Dodge truck is equipped with an electronic transfer case; otherwise, shift the transfer case lever from "2H" or "4H" to "4L."
     
   Tips & Warnings
   • Indicator lights will come on and alert you that your vehicle is in either the high or low range of 4WD.
     
   • Do not engage in the low range of 4WD drive if the transmission is in gear; you must shift to "Neutral" first.
     
   • Many Dodge trucks allow you to shift from 2-wheel drive to the high range of 4WD at up to 55 mph--consult your truck's manual to ensure that this is possible. Do not exceed 55 mph while engaged in the high range of 4WD. Do not exceed 25 mph while engaged in the low range of 4WD.
     
   • Do not engage in 4WD unless you are on slipper or rocky roads.
     

yes it could be

Check your transmission fluid level You will need to top it up if low. Low fluids mean that not only will the transmission be slow to respond but when it engages gear it does so with a bit of thump. If the fluid stays low this thumping of the gear changes will eventually shear off the input shaft. Also check the linkage located from beneath the gear shift to the transmission casing and adjust it if necessary. My guess is that topping up the transmission fluid to its proper levels will solve the problem without need for any adjustment

The bike has a bent shift for or two. The engine will need to come out of the bike and get a complete teardown. A shift fork moves a "slider gear" left and right on a shaft. Both sides of the slider gear have "dogs" that engage into the side of an adjacent gear. This is how the different gears are engaged. A bent fork will not slide properly or engage properly. It is a costly repair. Note that if the inspection reveals a broken gear tooth, the smooth shaft that the shift fork slides on could be bent, and/or the gear shafts could be bent as well.
Can I get a “very helpful” rating on this answer?