Rear Axle Compatibility

[nobby]

So i picked up on some website possible differences in the FF Rear Axle in that a company listed install kits for 1988-1997 and then 1998-2017. I was assuming that this more an internal thing. However i am looking at axle swapping the donor is a 1999 Suburban Full Float, will this be a direct bolt into my 1997 that currently has the 14 bolt semi?

Cheers
Nobby

 

[dbrannon79]

I believe it should be a direct swap. just check the spring and shock perch placements on both to verify. the yolk might use a different size u-joint, but the conversions should be readily available too.

 

[MrMarty51]

Might have to change backing plates and emergency brake cables for the emergency brakes.
The park brake cables could be different in lengths and styles.

 

[DieselAmateur]

If it was a 2500 suburban, it may have the 3.5" rear shoes which is a nice little upgrade as the 2500 pickups only had the 2.5" shoes. As Doug suggested verify that the spring perches are the same width which I think they should be. I swapped the rear end from a 1999 2500 onto my '95 2500 with no issue so you are probably good to go in terms of frame geometry.

 

[nobby]

If it was a 2500 suburban, it may have the 3.5" rear shoes which is a nice little upgrade as the 2500 pickups only had the 2.5" shoes. As Doug suggested verify that the spring perches are the same width which I think they should be. I swapped the rear end from a 1999 2500 onto my '95 2500 with no issue so you are probably good to go in terms of frame geometry.

I see you went from 4.10 to 3.73, how are you liking that i am moving up because i occasionally Tow and the 3.42 just is not enough. I am torn between 3.73 with my current 245 tires or 4.10 with 265 but i am thinking for the amount of times I tow heavy ill hate going to 4.10.

 

[DieselAmateur]

I really like the 3.73 gears, it is a sweet spot in my opinion. I've never run 3.42 but the 4.10/ 4.11s were terrible for highway driving. Winding out the engine to 3k rpm just to go 70 wasn't fun. I do have a manual transmission though and that helps with towing and fine control over rpm gearing and whatnot especially when towing.

I have always run 265/75/16 tires regardless of ratio. I'd also think that going from 3.42 to 4.10 would kill your fuel mileage which sounds like it's not worth the tradeoff given how infrequently you tow heavy.

 

[Will L.]

Haha- you ought to try 5.13 and 12.5” wide tires with a vertical windshield! Now that kills the mileage towing!