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14 Bolt FF Differential Swap

Monduke

Monduke

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Joined
Jun 19, 2018
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Bay Area
Hey everyone,

New member here and I just bought a 1990 Blazer. Right now it has a spool diff in the rear and since this is my daily driver I'm chirping around every turn. Luckily the guy I bought it from gave me the open diff in case I wanted to swap them out and thats exactly what I want to do. I want to do it myself but I haven't been able to find any existing threads going over the process. This is going to be a first for me so the more information you can give me the better!
 
Take the shafts out first. Then the bearing caps. Mark em with a punch first,then adjust out the side adjusters 2 rotations on each side. Then the carrier comes out.
 
Also you can search Detroit locker install. Same procedure essentially. Just using different parts. Make sure your open diff kit they gave you has all the thrust washers
 
Gotcha, and when you say side adjusters that's #1 in the picture right?

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Correct. Those are threaded. They adjust left to right.
 
Alright, I've been giving this more thought and now I'm thinking about changing my gear ratio while I'm down there. First off, is this something I can do myself? I feel I'm pretty mechanically inclined and have access to dial indicator's, but this would be my first time doing axle work. Also, I need some advise on what gear ratio to change to. I'm running a Dana 60 and a 14 bolt ff 1 ton with 37" tires. currently has a 4.11 ratio (at least that's what the craigslist ad said). I was thinking 4.88? would 4.88 work with a larger tire, maybe 40"s?

I appreciate the help!
 
Your motor and transmission specs matters in that decision. We need that to guide you a little better. It is one of the easiest axles to do but not without some learning curves. From that bible article I linked is an equally in depth gear setup article.
 
What is your intended use of the vehicle? If you plan on driving this on the street for any distance I would no go about 4.11 without overdrive. I recently changed my axle gears to 5.13s but I swapped from a SM465 to a NV4500. I can run 70 MPH @2400 RPMs with 37s and have plenty of power to tow with. It all depends on how you plan on using the truck.
 
Also I reccomend a crush sleeve eliminator kit for the pinion gear. Depending on the carrier size you may need thick cut gears.

20180328_111039.jpg
 
Hey guys, I really appreciate all the feed back on this, but I have some new info that's going to change some things. I stuck my head under the truck and found a "Jasper engines and transmission" sticker on the transmission. I called them up and it turns out that this truck had a 4L60 trans installed back in 2012. The guy told me it has 4 speeds, 4th being overdrive.
 
4l60 is an electronically controlled 700r4.

Which is what you should have
 
The 14B FF in the rear is a good one to learn gear setup on. Its a bit easier with the adjusters. The front 60 is going to be harder. Also did you have a full spool or mini spool in the 14B? In addition to dial indicator you should have a press, bearing separator plates, and an inch pound dial type torque wrench to check pinion preload. For the 60 you are supposed to use a case spreader to get the center section in right.
 
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