Well, it all depends on which tranny is behind your 302,and what the factory axle ratio(s) are.A 302/5-speed/3.55 gearing combination was given a 4,000 lb. rating.A 302/AOD/3.55 combination was given a 7,700 lb. rating.The 302/AOD/4.10 was given a 8,000 lb. rating. The manual rating was lower due to warranty concerns(owner's needing the clutch replaced from a lot of wear), that dealerships just didn't want to deal with(no pun intended....)often.You can find out what ratio your '89
Bronco came with from the factory by looking at the data sticker inside the driver's side door jam.Most likely you'll have an "H9" under axle code.This is a 3.55:1 with a rear limited-slip.An open 3.55:1 would be "19".The optional 4.10:1 will be an "H5"(rear limited-slip).The only way your
Bronco could get the steeper 4.10:1 gears is with the 302/AOD.Some 302 Broncos received the C-6,three-speed automatic,but that was a running change from mid-1990 models to a R.P.O. for 1991,so if your 302 has an automatic behind it,it's the AOD.Tranny codes for 1989 Broncos are :
K=C-6
T=AOD
M=5-speed
Z=HD 5-speed
F= 4-speed
Hope this helps.
