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Clutch Selection

This is where I hit a brick wall. I had read several places that you could use a factory clutch setup for the vehicle the trans was going in with this swap. Well that was bad info for me and my parts setup which caused me a lot more work than necessary. Hopefully I can spare someone else that trouble.

The NV3500 has been around since the late 80s in the GMT400 platform (88-98 trucks). It is called by several different names over that model year run but the early ones used and external slave cylinder that pushed on a clutch fork much like the mechanical linkage setup that would have been factory on a C10. I can only guess that on that style trans you could use a clutch setup for a C10 and it would work perfectly fine. In my case with the internal hydraulic bearing it didn’t work. I had a slightly used 10.5” clutch setup that I had gotten from a friend. It came with everything clutch related that I needed including a 153 tooth flywheel that I bought a brand new starter for. Well I noticed that when I put the trans on the engine it kept springing back when I pushed it up on the dowels and I had to draw it in the last little bit with the bellhousing bolts. I thought that was odd but I also don’t know a ton about clutch setups so I thought it might just be normal because of the pressure plate. Well it wasn’t and once I got the rest of the truck together it wouldn’t move because the clutch was never engaging. It wouldn’t even engage enough to make a burning clutch disc smell. That’s when I found out I needed to use a clutch for late 90s C1500 for proper operation. I don’t think you can use a S10 clutch as they might use a smaller 11” flywheel but I’m not 100% sure on that. In order to avoid buying the wrong parts again I just used a C1500 clutch as the flywheel sizes looked to be the same between it and the one for my C10. The difference in the pressure plate heights was right at a ½” and explains why it would never engage. Once I looked at the pictures of the two pressure plates I could tell the difference and knew I had found my issue.