2:56 vs 2:73 vs 3:08

[Eli77]

hi all. I broke the rear differential of my 86 m998 sent it to rebuild. And at the same time thinking to myself should I upgrade the ratio of both front and rear . From 2:56 to 3:08 ? Would that be a good way to go ?

 

[Coug]

Do you like being able to drive 55 mph? If so, then DON'T switch out to a slower gear ratio. The 2.56 is the fastest speed gear set made for these trucks. The other two gearsets are for 4 speed trucks that are also heavier.

The only advantage would be is if this is a dedicated off road rig that needs a little slower speeds/higher torque.

 

[Eli77]

Thx. I am. Actually able to drive 65 mph. With 6.2 3 speed so I guess I will stick to the 2:56

 

[Coug]

Thx. I am. Actually able to drive 65 mph. With 6.2 3 speed so I guess I will stick to the 2:56

This isn't so much for you, but for anyone else that comes on here and wants to argue about how fast it's okay to drive a 3 speed truck.

book top speed is 55.

the 6.2 and 6.5 GM engine have heat soak issues, so running for extended periods of time above 55mph can lead to engine failures. Specifically cracking in cylinders 7 and 8.

The 6.5 GEP has better metallurgy, so the heat soak isn't so much of a problem.

Of course, if you have tires that are larger than 37" that also changes the RPMs that the engine is running at and the amount of heat being produced by the engine.