Hi my nissan skyline v35 sedan 350gt stop shifting to upper gear after 20 min of driving. I brought this car morethan a year ago and rebuild the engine. Everything is going good but when I test drive it yesterday gear stop shifting after 20 minutes. I can drive to reverse and first gear only. I suspecting the old owner put a different oil and drive it hard thats why the engine get cooked and looking online I cant find the proper transmission oil and filter. Any advice how to fix this problem pls thanks
