I recently purchased a 88' Iroc-Z L98 w/a 2.77 rear as a second because my 95' Trans Am's rear decided it didn't like the 383 I recently built for it and I needed something to drive until I get it fixed. I love this car but am having a few tranny problems.
First, if you hop on it from about 30 MPH, the car downshifts but it slips like crazy and then it at WOT it doesn't want to shift until almost 6g, so I have to left off of it. I also found a TV or Clutch correction kit in the glovebox and no idea what to do with it. Second, I checked the tranny fluid and is in desperate need of changing but I was told if I change it the tranny would start acting up even more because it has grown accostumed to the fluid. I was wondering if there is any truth to that. Third, my car has the BW Posi but when I roast sometimes I get a peg leg with no sign of the left tire spinning. Sorry, if this post is too long or if I sound like I rambling on. Any help is apprciated in advance.

Thanks,
Brian

 

The trans may or may not have problems if you change the fluid, its an iffy thing. You could try siphoning out about 2 qts of old fluid and add 2 of fresh fluid, then drive it for 6 months or so and take out 3 qts and replace with new, do this a few times every 4-6 months then change the fluid and filter, might be less of a shock to the trans that way.

Change the differential fluid and put in the limited slip additive, hardly anyone ever changes diff fluid.

The shifting at 6k might just be that the tach is off up in that range, it happens with age. When my car was new it would shift at 5500 RPM when floored, so 6k could just be tach error.