What gears

[Schurkey]

Much cheaper to just get a junkyard diff with 3.73s already inside. It's a common ratio, shouldn't be difficult to track down.

I found a 91 Chevy long bed 4x4 differential with 3.73 for 350

This is the front differential, right? Is it the right style? 8.25 vs. 9.25? The 8.25 would be much more common, used on K1500s and light-duty K2500s.

"I" would consider re-sealing it, verifying that the thermal actuator works, and at minimum, fresh gear lube before installing the thing. Converting to the newer-style actuator is a popular upgrade.

 

[Keeper]

Do we know the gearing currently in the front diff? Just making sure it wasn't already a GT4 truck. That would suck to find out later.

 

[Lguzman9]

I took out the current differential and it was 3.73 so no need to be replaced but 4x4 didn’t work when I got it and it went to 40 mph but just revs after 40 mph

 

[Caman96]

took out the current differential and it was 3.73

Wait…I’m lost, so it originally had,has 3.73 gearing?

 

[Lguzman9]

The guy told me he swapped the rear differential for 3.73 and that I needed to swap the front because he didn’t know what gear it was and that the 4x4 should work once I swapped