Similar sitauation
I have a 98 stang gt with the t-45 and had a similar situation. It sounds like the throwout bearing, thats what happened to mine. The trans would squeal really loud in 1st, 2nd and 3rd. It sounds like it's ripping apart, then would quiet down in 4th. As far as the reving goes, that could be the idle air control on the throttle body. In the summer they seem to rev up when coming to a stop and in the winter it revs really low (almost cut off) when coming to a stop. I'm not a mechanic by no means but i hope this will help out.
I have a 98 stang gt with the t-45 and had a similar situation. It sounds like the throwout bearing, thats what happened to mine. The trans would squeal really loud in 1st, 2nd and 3rd. It sounds like it's ripping apart, then would quiet down in 4th. As far as the reving goes, that could be the idle air control on the throttle body. In the summer they seem to rev up when coming to a stop and in the winter it revs really low (almost cut off) when coming to a stop. I'm not a mechanic by no means but i hope this will help out.
As far as the IAC goes, put a new one on. As far as the throwout bearing and/or clutch goes, whew thats lot of work, if it's the tb. I would start with whoever installed it but chances are it's been 6 months and they usually guarantee their work for about 30 days. Man that sucks but try to find any reciepts,etc. I suspect this is the problem but i hate to tell you wrong. No it should last years if it's new. But i will say that the noise will probably go away, however, it will not be a good smooth shift. Man you need someone to look at that trans. If the shop used the correct pilot shaft tool to line up the clutch,etc. Then the trans should be right against the engine, no gaps whatsoever. A proper lined trans will slide right into place, also there's 2 pegs on each side of the trans to hold in place, all this has to be lined up properly. Hope this helps
Because if it wasn't, it couldn't be installed.