Gear ratio and cpu

Asked by Mar 19, 2017 at 04:01 PM about the 1994 Chevrolet Blazer Silverado 2-Door 4WD

Question type: Maintenance & Repair

Is there a difference in ecm on 1994 chevy blazer
when it come to 3.42 ratio and 3.73 ratio? I switch
to 3.73 and now i keep going into limp mode

4 Answers


is it a 4X4? and did you change both axles? if not then you suv is fighting its self to go forward due the difference in gear ratio.

Yes its 4 wheel drive and i did switch both differentials so that they match.. i have asked alot of people and noone seems to know everyone is puzzled.. there is no slippage or anything in trans it just out of no where will go into limp mode


It should still run and drive like normal just with the speedo off by a few mph. I'm thinking you have another problem


ok so heres my next idea, try driving it maybe 1 mile or something listen to the motor and transmission and suspension, if you hear a roaring noise (like a motor in over rev) before stopping check your RPMS on your gauge and if they are above 2000 then its you motor makig the noise HOWEVER if its not lift the vehicle and rotate the wheel by hand and listen for grinding if it grinds replace the wheel bearing on that wheel. or if none of the above check your transmission fluid level, color, thickness, and smell, and don't forget to check the fuses and stuff it could save you some work. also while your at it check oil level and color. if no results just get back to me and i will help you further

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