Posted by Joe Lorenzino on Tuesday, May 18, 2004 at 1:25AM :
In Reply to: ratio question posted by arthur p bloom on Tuesday, May 18, 2004 at 0:49AM :
Definately 2 different ratios based on 2 different pinion tooth counts. I haven't seen the actual gears used in these sets, but my guess is that the 4.88's are a 8/39 set, while the 4.89's are a 9/44 combination. The first number being the tooth count on the pinion, the second, on the ring gear. It was a common practice in the past to put a slightly "faster" ratio in the front axle sothat it would "pull" slightly when engaged. This is where most of the warnings about driving in 4x4 on a hard surface originated from. In mud or "soft" conditions, the front axle pulled or lead the rear slightly, but the surface itself absorbed the difference. On a hard surface, especially heavily loaded, the driveline would "bind up" quite quickly until something released the presure. I had an old 3/4 ton that had 4.09's in the front, and 4.10's in the back, which was quite common. I also remember that this ratio difference was one of the reasons that the shackles were at the front end of the springs on the front of some trucks.("pull from the front, push from the back" seemed to be the logic)J.V.L.