MoFoChance20

Hey guys I'm new on the Forum and was wondering if you could help me out. I have a 98 Firebird Formula with the LS1 and 4L60 tranny and I can't figure out if I have the 2.73 3.08 3.23 gears.

94_LT1_TransAm

There should be a decal on your Driver side door that has a bunch of three digit codes on it, depending on what gear ratio the car came with it will have its own code. GU2= 2.73, GU4= 3.08, GU5 3.23, GU6= 3.42. with it being a stock 98 formula, I'm assuming, it should have 3.23 with the G80 code which is Posi trac (limited slip) Hope this helps!

MoFoChance20

Thank you!!

RPM WS6

iTrader: (3)

3.08 was not an option for any year of 4th gen with an LS1/4L60E combo, it would have to be 2.73 or 3.23. As outlined above, you can check the SPID sticker for GU2 or GU5 codes to determine which ratio it came with stock.

McGinnis

Almost guarantee you have 2.73, the 3.23 usually only came with WS6 cars as a performance package. A quick way to tell is if your car cruises at 80 mph at about 2000 RPM then you have 2.73, if its 3.23 you will be at around 68 mph at 2000 RPM.

MoFoChance20

Cars been repainted so I don't have door sticker but at 65 it's at about 2000rpm so it'd be a 3.23 thank you!!

FirstYrLS1Z

iTrader: (4)

If it still has the original driveshaft,2.73s' got a steel driveshaft.3.23s' got an aluminum driveshaft. 2.73s' had a plastic tab at shift selector to prevent manually engaging 1st.

RPM WS6

iTrader: (3)

Plenty of base trim level A4 LS1 F-bodies came with 3.23s, though it was an extra cost option. My '99 Z28 was optioned that way when new on the dealer lot as regular inventory, not a special order.

It was, however, mandatory on WS6, WU8 (SS), or WU6 (Firehawk) when MX0 (auto trans) was selected.

This is correct.

This was not the case for LS1 cars; only older LT1s.