99 Tahoe and starter/flywheel

[slam59]

Replaced my strarter on my 99 2 door 2wd Tahoe about 3 weeks ago and flywheel was decent shape but not too bad. Now last night it sounded like it had a slight grinding noise for a sec before starting. I started it up this morning and it definitely had some grinding noise going on before starting. So question is, you guys think its the flywheel making the noise and I should of replaced it? Is it a major job to do this? Also, I was told that these 99 2 door 2wd Tahoes came with 2 different transmissons. I thought they all had the same tranny. How do you know which one you have? Thanks...