Trans Whine
 

Hey all, I have a 1995 GMC half ton 4x4, with the NV3500 5 speed manual trans, now aside from the clutch issue, and the syncros going in second, it has an incredible whine whilst driving with slight pressure on the throttle. I have absolutely no idea what this could be as this is my first truck, and first manual trans, but the trans should have that syncromesh gear oil in it, but the genius that owned it before me put 80 90 gear oil in it, No idea if that's the problem, but any info would be awesome, I just hope the tranny isn't going out of it...

Change to the correct oil.

Noisy U-joints?

I'm a firm believer in 100,000 ml fluid flushes and filter changes. Could very well be your Trans Case also

I agree with In2Trux.

My 98 GMC 4L80e had a terrible clunk and whine when I bought it. wheneve rit shifted to overdrive. I had the fluid flushed and within 1000 miles it was shifting beautifully. It had 135k on it when I bought it and considering how the brakes were still original, I would imagine that the fluid was as well.

My 02 Honda Accord 5spd started grinding when going into 5th at high revs about 5k after I bought it. I took it into the shop and had it replaced with Honda MTF... within 1k it was perfectly fine again.

According to my grandfather (GM retiree in carbeuration), automotive parts are built and tested and tested and tested again with a certain weight and type of oil in mind. At least in the 80s, they would build for a certain brand and type of oil, and then test them up to 50,000 miles in really rough or not ideal conditions. The idea was to build a 50,000 mile car... As we know now, many of these cars are still on the road.