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My rear end is trashed in my 88 K5

N

Nutro

1/2 ton status
Joined
Jul 16, 2020
Posts
128
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Location
Austin, TX
I'm still pretty new to all of this. I had noticed a little bit of a noise but thought it was the exhaust vibrating the frame so I ignored it. Well, I backed into my steep driveway (Nose down) and the next day saw a puddle of gear oil coming out of the pinion seal area. This morning I took it over to a shop and they put it on the lift. As soon as he removed the pinion flange the mechanic was like "Dude, your gear oil shouldn't be silverish looking, this isn't gonna be good" We put the new seal in anyway torqued the pinion nut down. When he rotated the wheel, it was making an awful noise. We pulled the diff cover and the fluid came out with tons of metallic flake in it. The other mechanic looked at it and saw some putting on the ring gear and mentioned the pinion bearing being toast.

I can't afford to do a full rebuild so he suggested I find a junkyard rear diff with the same 308 gear and check the fluid in it. Drain the fluid, put new wheel bearings in it, new axle seals and a pinion seal and drive it until I can rebuild my diff completely or I swap to a different diff all together.

Will a Suburban rear end fit from a 2wd? I wasn't sure if the rear diff was different between 4wd or 2wd. It's just the stock 8.5" 10 bolt rear diff in the Blazer.
 
Well crap, I just realized the rear diff from a 2wd is 5 lug and I have 6 lug.
 
Thats what I'm sitting here wondering myself. I wonder if all of the mounts are in the same place.
 
If the noise just started, it's possible you didn't completely trash it, but you are correct that swapping the whole axle may be less work. I don't know how the market is now, but 3.08 10-bolts used to be about free. You just don't know how long the new(er) one has to live. What size tires do you run? Might be a good time to find a set of axles and get away from lousy 3.08s.

I believe spring pad spacing was the same for all 1/2-tons, so up to 87 on pickups, 91 on Blazer/Sub. If you're willing to move mounts, there are newer 10-bolts to choose from. Some even have disc brakes.

Do you have G80 locker? Do you want a locker or LSD?

But think about any future mods like disc brakes, lift, tires, gears before proceeding.
 
housing the same . swap shafts and brakes . gear ratio check for same as front .

only other thing might be the shock mounts are swapped on 2wd to 4wd if i recall correctly .
 
Blue85 said:
If the noise just started, it's possible you didn't completely trash it, but you are correct that swapping the whole axle may be less work. I don't know how the market is now, but 3.08 10-bolts used to be about free. You just don't know how long the new(er) one has to live. What size tires do you run? Might be a good time to find a set of axles and get away from lousy 3.08s.

I believe spring pad spacing was the same for all 1/2-tons, so up to 87 on pickups, 91 on Blazer/Sub. If you're willing to move mounts, there are newer 10-bolts to choose from. Some even have disc brakes.

Do you have G80 locker? Do you want a locker or LSD?

But think about any future mods like disc brakes, lift, tires, gears before proceeding.
Click to expand...

Not entirely sure on the G80. I don't mind about it being open or posi at the moment, I just need something to drive on the street. Ideally, and eventually, I'd love to find a 14FF for the rear and whatever in the front but that is down the road.

If I could weld, I'd roll a 99-06 2WD rear end under and weld pads on that but that isn't a short term plan
 
Spring pads are cheap and there's likely someone around who could do the welding. The GMT800 axles are quite plentiful right now, but it seems like most are 3.42 and 3.73, so you'd have to check on that. You're also into a different lug stud, which might not be a big deal and likely would benefit from a different master cylinder. Not sure on banjo bolt size, but there should be some parts store hoses/bolts that would fit together.
 
Can you stay in 2WD until you're ready to regear the front?
 
Blue85 said:
Can you stay in 2WD until you're ready to regear the front?
Click to expand...

Absolutely. I bought this 1.5 years ago and haven't even used 4wd yet. My long term goal was LS swap, 14BFF/D60 etc and 35's for a cruiser/light offroad rig.
 
if swapping in another axle such as the 14ff in that pic you need 42.5" center to center on the leaf spring pads / or pull the axle from a 3/4 ton only .
 
Both those are 14bff good rear ends for our needs, bigger brakes too.
I would go this route. For future 35,s look for 4.10 r&p.
advise on shock mount and drive shaft compatibility.
You can convert your front axle to 8 lug, or wait for the d60.
Recommend a master cylinder for jb6 rpo code. For the 14bff and 3/4 ton discs
 
I believe that the 1/2 ton 10B axles have a spline count change at 1989 to 30 spline from 28. Keep that in mind if you find a 2wd version and want to swap axles.

I know that I tried a stock 15" rally wheel on a 2000 4wd rear axle with disc brakes, and the wheel wouldn't clear the caliper, so it wouldn't turn.

I personally wouldn't spend the money on D60 front for a cruiser that hasn't been in 4wd in the last year. There are more affordable options to get better brakes up front and a better 6 lug axle with possibly better brakes for the rear.

But I completely understand if that's the direction that you want to go!
 
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