I can speak for two cars here, as we did the trip together in July 2007 - my Scorpio and friend's Tavera. At start, the Scorpio had about 8000 on the clock and the Tavera about 18000 kms. 4 persons + baggage in the Scorpio and three + baggage in the Tavera.
Did Del-Pahalgam-Srinagar-Kargil-Leh-Pangong Tso-Khardungla-Sarchu-Manali-Del.
Neither car required ANY attention/repair whatsoever during the trip or after the trip.
Just lucky? Or can there be other conclusions?
We're planning a more elaborate repeat in Sept this year, to include Zanskar and Suru!
Rather surprised to read about the converted Gypsy above. Years ago, in 1997, I had done Kinnaur and Spiti in my Gypsy 1000. 3 adults, 2 kids and baggage. This was quite apart from numerous other trips in Himachal and Kumaon. Roads were worse in almost all sectors compared to what they are today.
Again - zero problems. Upon return from Spiti, there was a squealing sound audible at times. Got this attended to in Delhi - 2 'crosses' (universal joints) had a damaged bearing each (dust ingress past the seal) and were replaced. Cost was about Rs. 500/-).