7.5 or 8.8?

[kjohn]

I read somewhere on TRS that Ranger 4.0 engines all have 8.8 ring gears. My '98 Ranger (4.0, Automatic) has an axle tag that says 3 55 88 ????.

The rear wheel bearings I bought, telling the tech it was an 8.8 ring gear, were .250 too large. I exchanged them for the 7.5 rear wheel bearings.

Apparently not all 4.0 rangers have 8.8 ring gears.

Any comments?

Thanks

 

[martin]

there are two different 8.8 axles used in the rangers, 31 spline and 28 spline. That being so there are also two different wheel bearing sizes.

 

[85_Ranger4x4]

Most Ranger 8.8's use the same axleshafts as a 7.5.

 

[Beanmachine7000]

All 4.0L have the 28 spl 8.8 (which has the same shafts as the 7.5), only the Explorer and FX4 Lv II got the 31 spl 8.8...

 

[kcm1582]

I'm not completely sure but I believe that the first set of bearings that you got were for a 31 spline 8.8 instead of the 28 spline version. IIRC the 31 spline axle has a larger diameter axle tube and shaft which would account for the wrong size. As for the 7.5 bearings fitting, it could be a common part to both as they are very similar to each other.

 

[Yellowsplash]

Correct...it is a glitch in the parts store listing.

As said before, the 7.5" and 8.8" 28 spline share the same axleshafts and bearings.
The 8.8" 31 spline uses larger axleshafts and larger bearings.

 

[kjohn]

Thanks All, the parts guys did not show a difference for the 28 or 31 spline axles. I'll be smarter next time. Boy, were the races tough to remove.

 

[ElleShooTiger]

I too got the oversized bearing the first time I went to the store, returned them and got the smaller ones and they fit perfectly. Glad I got them at Advance Auto and didnt buy them from RockAuto with the rest of the new suspension, returning them would have been a lot tougher than driving 4 miles to the store!