Blkchevy's Truck Has Seen Better Days.

dietz4ibanez · February 11, 2008

Well guys my rear end is going bad. I'm kinda bumming about it but at the same time I am conniving some replacement plans.

First things first: My "Replacement Parts" card in my glove box says I have GT4 rear end. Thats a 3.73 right? I want to get my gearing right!

So here is what I am thinking about doing. My friend had an old 70's model 14 bolt rear end and he is checking on the gearing for me. I am wondering if he is really meaning that its a 12 bolt cause I have been looking through some parts catalogs and I am not finding any replacement parts for a 14 bolt rear end. If I get the 14 bolt I am going to get the 3/4 ton leaf springs too.!

Another thing is my rear end being that it is a 10 bolt is it 7.5 or 8.5?

Let me know what you guys think or if you have nay ideas.

Zembonez · February 11, 2008

When you say it is "going out" do you mean it's getting noisy?

If so, the easiest / cheapest route mught be just replacing the bearings in the current rear end. Used units that are 10 years old are likely not much better than it is now. Obviously, if you do end up replacing it, you want to get the same ratio as the front axle in order to avoid having to replace that too.

RaysZ71 · February 12, 2008

There were 14 bolt and 12 bolt rears. the 14 was a 3/4 ton 8 lug and the 12 was a 1/2 ton. I really doubt that a 12 bolt that was available in the '70s trucks will bolt into a '98. There were a few years that there was a heavyduty 9.5" rear that fit the 88-98 trucks. It was also used in the light duty 3/4 ton that used 6 lug wheels. I want to say the 1/2 ton option was F41 HD suspension. I think all 94 and up 1/2 ton diesels used these as well.

dietz4ibanez · February 12, 2008

Yeah my rear end is whinning like crazy and is clicking/grinding really bad when decelerating and the universal joint is fine.

I am not worried about a direct bolt up installation. Just got done putting a ford 9" in a 3rd gen firebird/trans am/camaro and equipped it with an LS1 out of a newer body style camaro.

The 14 bolt rear end is free if I want it and I think that I can install it cheaper than buying the ring and pinion set. I can also get a G80 3.73 locker. But I am just looking at my options!

The only other thing about the 14 bolt is I dont know if I can switch out the drums for a 6 lug....?? Its kinda weird cause my drum brakes need replacing at the moment!

dietz4ibanez · February 12, 2008

GT4 Rear end is 3.73 right?

2000DV4.8 · February 12, 2008

GT4 Rear end is 3.73 right?

Yup.

http://www.gm-trucks.com/home/index.php/RPO-Code-Lookup.html

dietz4ibanez · February 12, 2008

is it possible to equip the g80 in this member?

RaysZ71 · February 12, 2008

Yeah my rear end is whinning like crazy and is clicking/grinding really bad when decelerating and the universal joint is fine.

I am not worried about a direct bolt up installation. Just got done putting a ford 9" in a 3rd gen firebird/trans am/camaro and equipped it with an LS1 out of a newer body style camaro.

The 14 bolt rear end is free if I want it and I think that I can install it cheaper than buying the ring and pinion set. I can also get a G80 3.73 locker. But I am just looking at my options!

The only other thing about the 14 bolt is I dont know if I can switch out the drums for a 6 lug....?? Its kinda weird cause my drum brakes need replacing at the moment!

The axle shafts are either 6 or 8 bolt. So if the 14 bolt is a 8 lug, you will need to replace axle shafts with the 6 bolt version.

Also your ujoint may be a different size.

454ss · February 12, 2008

10.5 inch 14 bolts are full floaters and are 8 lug only, they will have a bigger yoke on the pinion for 1350 series u-joints. 9.5 inch 14 bolt was lt duty 3/4 tons and heavy 1/2 tons and is semi floater with 6 or 8 lug available. as long as your not running a big block and you keep your small tires on there the factory g80 will live but any more power and tires over 33inch and its time to upgrade to a detroit locker.

dietz4ibanez · February 12, 2008

I know now that this rear end that I am looking at is a 14 bolt 6 lug just trying to figure out the gearing without unbolting the diff. cover and counting the splines.

GMSea97 · February 13, 2008

I have the 14 bolt 9.5" in my 97 GMC. It has kicked the bucket to say the least. They are almost impossible to find. The G80 is basicly just a locker option, and the HD code for the 88-98 truck was f44. I am looking into putting an 8 lug 14 bolt 10.5 into my GMC. That maybe a route you want to look at. You have to convert the front over to match 8 lugs, but if you do a web search it is a pretty popular and easy switch. If you find any good info on the 9.5" rear throw it my way. I have been trying to source a exact rear for almost 4 months, seems there are not any on the eastern shore.

GMSea97 · February 13, 2008

Here is a link on switching a 6 lug front to an 8 lug setup: http://coloradok5.com/8lugconversion.shtml

dietz4ibanez · February 13, 2008

Here is a link on switching a 6 lug front to an 8 lug setup: http://coloradok5.com/8lugconversion.shtml

Is there any way to change that rear end that you are looking at from a 8 lug to 6. Or is it not a floater like the rear end that I am looking at?

GMSea97 · February 14, 2008

I don't think you can take a full floater rear and make it 6 lug. I maybe wrong though.

dietz4ibanez · February 14, 2008

I was told that on the floater 14 bolt rear ends that you can replace the 8 lug axle shaft with a siz lug. Cause the 14 bolt that I am looking at is a 6 lug.

I just got these tires and rims so I am kinda partial to keeping them!

Does the 8 lug conversion for the front end strengthen/weaken the perf. & truck suspension longevity?