1993 RWD Astro rear end starting to go

IF YOU HAVE QUESTIONS ON THE REAR DRIVE SHAFT OR AXLE, IT GOES HERE.
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BayAreaAstro
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1993 RWD Astro rear end starting to go

Post by BayAreaAstro »

Hi there,

The rear end on my '93 is starting to go. Sounds like the brakes are grinding but they're new. The guys at the oil changing shop also tell me that my diff oil is dirty and needs replacing. The brakes are new so I'm sure the rear end is on its way out. Wheel bearings most likely.

I don't have a garage or spot to work on it but I can lean on a friend to make room for a day or two. Local wrecking yards have a 2000 and a 1998. An independent seller is parting a '96. Can any of those rear ends (drum to drum) swap in without major issues? I don't mind making a few mods to get it to fit. Just thought I'd ask instead of going blind.

Also, what should I look for when making a decision? Besides, low mileage. What's the easiest way to figure out gearing?

Thanks in advance!

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WoodButcher
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Re: 1993 RWD Astro rear end starting to go

Post by WoodButcher »

RPO codes on the sticker on the passenger door jam or glove box door will tell you what it came with.
GU2 2.73 ratio
GU4 3.08 ratio
GU5 3.23 ratio
GU6 3.42 ratio
GT4 3.73 ratio
GT5 4.10 ratio
GQ1 Open Differential Rear Axle
G80 GOV-LOC Rear Axle

The '93 is a gen I with composite springs. The years you listed are gen II steel springs. '96-'02, (in '03 they went to 6 lug 16" wheel w/ disc, whole nuther beastie) Most guys convert to the steel but you'll need the front hangers for the steel springs. The way the spring is captured in the front of gen I is different as well as the composite being a 1/2 wider.
You'll have a few simple mods to make but as long as you have the front spring perches you'll have no big issues. Worst part is removing the 2 bolts from the drivers side spring perch. They were installed before the tank was. in order to remove them w/o dropping the tank you need to cut the heads off and pull them to the outside. They are hardened steel so a sawzall will take some time, no room for a grinder but I'm told a plasma works well. I flipped the bolts in my '93 when I did the fuel pump and had the tank out but if I had to I'd do like Astrowill did and use my plasma cutter. (loosen the bolts so you can cut off the head then make a heat shield from sheet metal to keep the sparks and slag from the gas tank)
'93 Safari shorty, 350 swap
'05 Astro AWD, lifted, 6 liter, cammed, ported and programmed for fast.
'69 G10, straight 6, 3 onatree, jumped at me when I had a pocketful of cash looking for a spare astro. :)

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Re: 1993 RWD Astro rear end starting to go

Post by Captn. Crunch »

Before you go thu all the trouble of swapping out rear ends, I would inspect your axle bearings. They are not that tuff to do. If it is just bearings make sure to flush out the entire rear end. Pumpkin, axle housings the works. If it's a failed bearing the debris will be everywhere. Good luck
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

Topic author
BayAreaAstro
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I am merely driving my van
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Joined: Mon Feb 23, 2015 2:59 pm

Re: 1993 RWD Astro rear end starting to go

Post by BayAreaAstro »

Thank you very much for the replies. Good to know about those bolts over the tank. Going to look into rebuilding the rear-end. I can tackle the job if not too tricky and if it doesn't require specialty tools. I mean, why swap in a rear end that's just as old if it might go out soon too? Any good resources on rebuilding?

Is case I run into a low mileage Gen I....Is is safe to assume any Gen I ('85-'94) rear end will swap in?

Thanks again!

R.

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Re: 1993 RWD Astro rear end starting to go

Post by Captn. Crunch »

[quote="BayAreaAstro Going to look into rebuilding the rear-end. I can tackle the job if not too tricky and if it doesn't require specialty tools.
R.[/quote]

Re-building the rear end is tricky. It's actually arguably the trickiest possible thing you can do to a vehicle. Some refer to the ability to set up a rear end as a black art. Sorcery can be involved and I've heard tell of extreme cases involving sacrifices. Here is a link with some step by step so you get a feel for what you're looking at;

http://www.s10forum.com/forum#/topics/19061?page=1

Specialty tools will be required which ones depend on how deep into it you go.
Outer axle bearings, races and seals will require you to pull the axles but doesn't involve disturbing the ring and pinion gears. Carrier bearings will require that you pull the center chuck and now you're "into it". EVERYTHING MUST GO BACK EXACTLY AS IT WAS. If your lucky it will fall back in spec. If not, your resetting pinion depth and backlash as you re-shim again and again. I've done mine three times and it's still not exactly right. So read up on it. Watch utube videos. It's a patience thing. There's a bit of math involved. But if you pull it off, you will have done something most back yard mechanics can't say. " ya I re-built the rear end".
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s
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