Most people prefer to self-drive or self-ride to Ladakh by their own car or own bike and some also prefer to self-drive or self-ride to Ladakh by hiring a bike or car. In any case, hired car/bike or personal car/bike, idea is to live the passion of driving or riding through one of the toughest and adventurous terrains accessible in India. You can take your own or rented, car or bike to Ladakh but one must be careful while driving or riding through slushy roads, snow and water crossing or nallas. Also, it is always handy to learn little maintenance tasks of your vehicle prior to the start of this arduous journey in which you will be desolated majority of the time. For cars, although an SUV/MUV is good to have and a 4WD SUV will definitely help but I have seen hatchbacks (including Altos and Nano) and sedans doing good enough job on Manali - Leh Highway. However, with sedans / hatchbacks, one must drive with extra care and caution.
Also, be ready for few scratches or sacrifice some parts on your sedans/hatchbacks underbelly due to the lack of enough ground clearance which may be required in some water crossings or landslides on Manali - Leh Highway. If you are trying to attempt in a hatchback or sedan, I will suggest planning the journey late in the season (August - September) when the roads are in good shape than early season. Whenever in doubt, always step out of your car, walk down the path, inspect with your foot and plan the path of exit before crossing a dangerous landslide or water crossing on your vehicle. You can also park aside and see how others are crossing the risky section to plan your route of escape.
In deep water, crossings try to maintain the momentum without any half clutch measures and complete the entire stretch in one go only. Similarly, in slush stretches do not force the issue rather keep the smooth momentum with required speed to pass you through, without half clutch measures. Do keep an eye on the direction of the vehicle too. If you get stuck in slush then try to back and forth your vehicles to get out of the stuck position. It is always handy to ask your fellow co-travelers to get out of the car and push the vehicle from behind in case the car is struggling to pass through the slush or water crossing stretch.
Basic toolkit, screwdriver set, small hammer, puncture repair kit, iron rod, two or three "2 LTR" empty bottles of Pepsi / coke / limca etc to carry extra petrol or diesel (jerry cans will leak, cold drink bottles do not leak), funnel, towing rope, spare tube (must for bikes), elfy or fevi quick (2-3 sachets), jump start cables/wires, M-seal to prevent leakage etc. were among the few things which I carried along on my trip to Ladakh. Also, do not forget to get your vehicle (car/bike) serviced about 2-3 weeks before the start of the Ladakh journey. This will ensure that you have proper time in advance to test your serviced vehicle and get fixed any hitches that may have been introduced in that service.
Hiring a Private Taxi
All taxis (except Ladakh registration number) having taxi number or tourist permits number plates are only allowed for a drop in Leh - Ladakh. They are not allowed to be driven in Leh - Ladakh and as per the taxi union rules, only taxis with Ladakh number are allowed to roam in the Ladakh region for sightseeing. If you want to travel within Leh - Ladakh in your private taxi hired from a place other than Ladakh then in that case you need to hire a taxi with private number plate only. However, in the latter case be ready for some queries by the local taxi drivers in Ladakh or police constables on your route. You need to ensure everyone interrogating with you that the vehicles are not hired.
Whenever, you need to hire a taxi always try to hire it from Manali, as the drivers of Manali will always be more skilled and more accustomed to the route or current conditions of Manali - Leh Highway. Secondly, the locals always have a majority with an advantage of local support in any hurdle you might face on the way towards Leh.
To hire a taxi, go directly to Manali taxi stand and bargain hard with the local drivers only, for a drop to Leh. Do not involve any tour operator or hotel staff at any stage. The local taxi drivers will charge about Rs 1000 extra for a planned night halt on the way to Leh. The charges are close to Rs 12000 to Rs 17000 for a drop to Leh from Manali, depending on your bargaining power, tourist rush and time when you are visiting the place. June being the highest paid and September - August being the least paid.