I have a 69/70 VW pan with a 1500 CC motor. I purchased this car about 3 weeks ago. Here is my issue. At times when going up a fairly steep hill in 4th gear with two people in the car, it will kick out of gear. It also happened once while in 3rd gear. I don’t remember it happening when I was alone. Just having the extra weight it does it occasionally. Is there any adjustments can be made? By just putting just a touch of pressure on the shifter, it doesn’t pop out. Thanks for any help.