Neat map, why haven't I heard of this before?
CK5
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1990 GMC 1500 Jimmy
- Thread starter scpaul
- Start date
Neat map, why haven't I heard of this before?
scpaul
1/2 ton status
Drag racing is out of the question. If I were going to do something like that I'd start out with a completely different vehicle. I had a 64 Ply Valiant 2 dr. hard top, with a fully built 273+(bored) and a New Process 4 speed. It was called a "Daytona Hyper Pack" (look it up) and I didn't know it, so I really screwed up a car that would be worth bunchs. The factory only made about 700 that year I think. I did get it to turn low 13"s on a NHRA 1/4 mi. track and 109+ mph on soft street tires.
I have an LG flip phone. I can't get the back off to see which model.
The rear end that breaks, can I tell which one I've got without opening it up, or did they put different guts in the same housing?
It's going to be driven on the street, pull stuff (like Fords-just kidding) like my atv trailer, and misc.
Campfire, I'm going to pm you shortly.
Thanks again everybody, Paul
I have an LG flip phone. I can't get the back off to see which model.
The rear end that breaks, can I tell which one I've got without opening it up, or did they put different guts in the same housing?
It's going to be driven on the street, pull stuff (like Fords-just kidding) like my atv trailer, and misc.
Campfire, I'm going to pm you shortly.
Thanks again everybody, Paul
Sounds like you really don't need to mess with anything except the oversized tires, it's already perfect for street cruising. I'll echo Dean's comment above, an unmolested stock unit is a rare treat.
Check the RPO sheet for the G80 code to see if you have the Gov-lock. I'm betting you find it if the window sheet was advertising a locking differential. It will probably be listed next to the GT3 code for the 3.42:1 gearing.
Good question!? You seem to see all the other posts!
Only if they're in the Lounge or Garage. That's where all the action is...
Lol! Did you say you keep forgetting to click new posts.
To keep the thread on track... I owned i very stock 85 Chev K10 short box with the same options (minus the injection) 342 gears gov lock 700 4 speed auto 350 engine 33" tires Quad shocks up front very simalar. I thought it was fine to drive... and my dad drove it for years like that before i got it.
scpaul
1/2 ton status
I got a pic of the sticker. It shows a GU6 followed by the G80. What's the difference between the GT and the GU trans. designations? The tires aren't but 1 size larger than stock, according to the window sheet it came with 31x10.50R15 I put 33x12.50R15's on it. That is one size in hight and one size in width isn't it.
Actually two sizes bigger...you can get a 32x10.50 as well. The GU6 is 3.42 gears the G80 is the gov lock/ limited slip.
GU6 = 3.42 axle ratio (not trans). The axle codes are sometimes redundant, not sure why.
33" tires can be fine on there, what's not good is the shifting back and forth. By increasing the tire size you have now fooled the truck into thinking it's going slower than it actually is. When your speedo reads 65MPH you're actually going 69MPH (33"/31" * 65 = 69.2). Not a huge difference, but it will make the truck more gutless, leading to more downshifting. Again, it's the downshifting that is the problem, not the tire size or the loss of gearing.
scpaul
1/2 ton status
What do you think, which is the worst, the extra higth or the weight or both?
It's got 155,704 miles, I had to look.
It's not going to be just a pavement pounder. I hunt in the lower part of the state the most. If you want to see how you do in black gumbo sticky mud, come on down.
What all can you tell me about the different GT/GU ends. Do they have clutchs or if not, maybe I can use teflon in them to help. I'm a strong believer in it. You have to put it in properly, most people don't, so it doesn't do anything.
It's got 155,704 miles, I had to look.
It's not going to be just a pavement pounder. I hunt in the lower part of the state the most. If you want to see how you do in black gumbo sticky mud, come on down.
What all can you tell me about the different GT/GU ends. Do they have clutchs or if not, maybe I can use teflon in them to help. I'm a strong believer in it. You have to put it in properly, most people don't, so it doesn't do anything.
Width does not affect drive ratio, only height (circumference, if you want to get technical). The GU/GT code refers to axle gear ratio only, nothing else. Those codes get used with a variety of axles ranging from Cameros to dump trucks and everything in between. The Gov-lock isn't a clutch-based posi system, it is a mechanical locker that engages when the wheel speeds differ by a certain amount (controlled by a governor). The problem isn't so much the mechanism as that the carrier tends to crack and then grenade when it gets to the end of its life (often breaking other stuff in the process). FWIW, my gently-driven street truck saw its G80 carrier crack at ~130,000 miles. So the truck doesn't hafta be old and worn out to see a failure.
Here is what one flavor of gov-lock failure can look like. Sometimes the failure can destroy the ring and pinion teeth, too.
So we're not talking about clutch failures like a posi unit, these systems can be working fine and then suddenly fragment. Your mileage may vary.
So we're not talking about clutch failures like a posi unit, these systems can be working fine and then suddenly fragment. Your mileage may vary.
scpaul
1/2 ton status
Man, you really know how to make a guy feel secure. Ok, so I guess that there's no real warning. What's the fix; new complete axles or just the guts and how much am I looking at money wise? Around here we kill alot of jeeps. Will the Jeep axles hold up?
You can simply install a standard open carrier in the axle that you have (or some other locker of your choice). No biggie. You can also just run it until it blows, at which point you may also find yourself replacing the ring and pinion. But it's still not a lot of work, for me the problem is the uncertainty of being stuck on the side of the road at a random time. For stockish tires and non-abusive driving, the axle will hold up fine, it's just that optional carrier that is problematic. If you're in the habit of jeep killing...any axle will break if you beat on it hard enough.
And this is just the rear axle, the fronts didn't get the gov-lock option.
Cost-wise, you should be able to find an entire used 10-bolt axle for $100 or so, the carrier should be even cheaper. Earlier 10-bolt axles used 28-spline axle shafts, I think yours is new enough to be a 30-spline unit. I have an extra one sitting in a box, though I don't remember the spline count. Definitely determine the spline count before buying any parts.
scpaul
1/2 ton status
I've had a few people try to buy it. They wanted to give me 2 or 3,000 dollars for it. what would you say that it's worth to a 4wd enthusiest?
scpaul
1/2 ton status
I've never had a jeep, but I know quite a few that have. Any of the serious hunters with few exceptions have Chevy, Ford, or Dodge (Ram). On the Jeeps it seems that the axles and suspension do pretty good but the trans. engines and the misc. give alot of problems. I've got a 95 1500 chevy truck with almost 280,000 miles that the valve covers have never been off. I bet that it's got the same rear end, it's locking too. I changed the dope to synthetic about 3 years (about 50K miles) ago, I guess. I don't drive it much anymore.
Can't answer that without thorough pictures. Depends on region. I live in the rust belt. Trucks are cheap here but they are also usually rotted away from salt exposure (I can see through the sheet metal on all 3 of mine, and that's not rare). When someone brings a clean rig in from out of state, prices easily bid up over $5,000 for one of these rigs, depending on condition. But I bought all 3 of mine for $3500 total.
Selling price always depends on just who you get lined up to buy it. Some folks pay nicely for nice trucks, some folks would rather have a beater.
That truck could either have an 8.5" 10-bolt or a 9.5" 14-bolt rear axle. G80 was an option for either axle, so you have at least 4 combinations that could be back there. The 9.5" G80 doesn't have the bad rap that the 8.5" G80 does (though the designs are similar).
disenough
Registered Member
Where in SC. If I'm close I would help you some. I have brought a few of these trucks back to life.
scpaul
1/2 ton status
Mr.Enough, I would be real hard to find. I-77 passes about 5 miles exactly from my house. Including that intersection you have 3 turns and left at 1 fork. I'm right outside of Cola by about 2 streets. How familiar are you with the east side of Cola and how often are you down this way, not a special trip?
I really appreciate any help, but before I get too far, I've got to get some money ahead and I think that I would probably go ahead and get the engine done and some work on the trans. I'm thinking about having the engine brought up to a RV or a little more engine. It was getting pretty tired when I parked it. That's the main reason that I didn't keep the batt. charged and drive it once in a while. I'd also need to find a place to work on it. My wife would raise #e!! if I used the driveway. I just thought about a new set of hearing protectors I bought so my 300 Mag. won't deafen me. Besides, her lungs could probably use the exercise. If you want to, send your cell # to my email and I'll send some pictures.
Campfire, you said that I'd like to see 14 bolts on the rear end. How about the front? It has 6 or 8 lugs, I think 6.
Thank y'all very much, Paul
I really appreciate any help, but before I get too far, I've got to get some money ahead and I think that I would probably go ahead and get the engine done and some work on the trans. I'm thinking about having the engine brought up to a RV or a little more engine. It was getting pretty tired when I parked it. That's the main reason that I didn't keep the batt. charged and drive it once in a while. I'd also need to find a place to work on it. My wife would raise #e!! if I used the driveway. I just thought about a new set of hearing protectors I bought so my 300 Mag. won't deafen me. Besides, her lungs could probably use the exercise. If you want to, send your cell # to my email and I'll send some pictures.
Campfire, you said that I'd like to see 14 bolts on the rear end. How about the front? It has 6 or 8 lugs, I think 6.
Thank y'all very much, Paul
