Hi all....quick question, my '86 Blazer 4x4 with a 2.8 has a 4 speed man. tranny. I do mostly highway driving at 80+ kmh and was wondering if I found a replacement 5 speedwould the gear ratio be different enough to lower my RPMs and increase my mileage? What I'm asking is, does anyone know the final ratio of a 4 speed vs. the 5 speed that would bolt-in for this year? Thanks in advance for the help.

 

It really depends on what the ratios in your current trans are and what they would be in the replacement trans. If you have the stock 4 speed should be a Borg Warner T4 with gear ratios of 1 - 4.03, 2 - 2.37, 3 - 1.50, 4 - 1.00, R - 3.76. The most popular swap would be to go to the Borg Warner T5 which just adds a 5th gear at a 0.86 ratio for an overdrive gear. I believe the cases are the exact same length and should be a direct swap.