Front diff size?

[Christian ojeda]

I have a 93 silverado k2500 light duty with the 14b sf rear and 3:73 gears. So here comes the question, what type of front diff is stock with that setup and what front gears should I run if I'm looking at swapping 4.56's in the rear

 

[df2x4]

Should be an 8.25". I don't think the light duty 2500s got the 9.25" front differential, although I could be wrong.

what front gears should I run if I'm looking at swapping 4.56's in the rear

Also 4.56s. You want them to be the same ratio front and rear. Or were you asking for a specific brand recommendation?

 

[Christian ojeda]

Thank you, I thought it was 8.25. And I was asking because I cant find a complete front and rear kit and the closest I can is two separate brands, I was hoping Yukon. If you could just point me in the right direction with a link or what to look for that would be great. I want to do a 6 inch lift and 35s eventually after my 285's are toast

 

[df2x4]

I just did a quick search on Yukon Gear's website, they make 4.56s for both the 9.5" 14 bolt SF rear and the 8.25" IFS front. Make sure you have the 8.25" as opposed to the 9.25" IFS front though. I'm 99% sure you have the 8.25" but I've never really seen a 9.25" setup so I'm not much help on telling them apart.

4.56 for 8.25" IFS front, Yukon part number YG GM8.25-456R:
https://www.amazon.com/Yukon-GM8-25-456R-Performance-Gear-Differential/dp/B0078U8BGK

4.56 for 9.25" 14 bolt semi floater rear, Yukon part number YG GM9.5-456:
https://www.amazon.com/Yukon-Gear-YG-GM9-5-456-Pinion/dp/B0078U8LAQ

Personally Yukon wouldn't be my first choice, I checked and Richmond Gear makes the ratio you want for both diffs as well. That's who I would go with if it were my decision. Keep in mind that you'll need install kits with marking compound for both sets of gears. You can search for all of this stuff on the manufacturer's websites, they usually have pretty accurate parts databases.

Yukon Gear:
https://www.yukongear.com/

Richmond Gear:
https://www.richmondgear.com/

 

[Christian ojeda]

Much appreciated with the advice and I'll make sure to do the research for when I'm ready to start the project

 

[evilunclegrimace]

The easiest way to identify to front diff is very simple. If you have six lug nuts per wheel you have an 8.25" front differential, if you have eight lug nuts per wheel you have a 9.25" front differential.

 

[DerekTheGreat]

Are the axle flanges between the 8.25 & 9.25 the same?
I've heard of people swapping out their 8.25 for the 9.25, just never verified if everything else has to go with it. I'm looking into buying a 4x4 2500 8 lug Suburban parts car..

 

[evilunclegrimace]

Are the axle flanges between the 8.25 & 9.25 the same?
I've heard of people swapping out their 8.25 for the 9.25, just never verified if everything else has to go with it. I'm looking into buying a 4x4 2500 8 lug Suburban parts car..

No

 

[The_Full_Monte]

Hi, gents. I have a '99 K2500 Suburban LS.

Question: is the front diff regular or reverse rotation?

Reason I'm asking is because I'm thinking about lowering my factory 4.10s to 3.42s. I do zero towing and about 80% of driving is highway and interstate. With 4.10s and 4L80E transmission (0.75 overdrive), anything over 55 mph (~2,000 engine rpm) feels like I'm pushing the 7.4 Vortec's guts out. 70 mph feels like absolute maximum cruising speed (~2,500 engine rpm @ 70 mph). I'm usually cruising anywhere from 65 mph to 80 mph. This isn't a fuel efficiency thing. If I wanted 20 mpg, I'd have 1500 Silverado with a 5.3 Ecotech, Active Fuel Management, and a 6L80E or 8L80E transmission.

 

[The_Full_Monte]

Hi, gents. I have a '99 K2500 Suburban LS.

Question: is the front diff regular or reverse rotation?

Reason I'm asking is because I'm thinking about lowering my factory 4.10s to 3.42s. I do zero towing and about 80% of driving is highway and interstate. With 4.10s and 4L80E transmission (0.75 overdrive), anything over 55 mph (~2,000 engine rpm) feels like I'm pushing the 7.4 Vortec's guts out. 70 mph feels like absolute maximum cruising speed (~2,500 engine rpm @ 70 mph). I'm usually cruising anywhere from 65 mph to 80 mph. This isn't a fuel efficiency thing. If I wanted 20 mpg, I'd have 1500 Silverado with a 5.3 Ecotech, Active Fuel Management, and a 6L80E or 8L80E transmission.

After deep diving on the interwebs, it appears the front diff is reverse rotation.