Rear axle choice for 1/2 ton

[TheBac]

Rear axle choice for the 1/2 ton

Since the 11.5" out of the donor was bent and not usable, I've got to find an axle.
Im hoping to get some advice on the GM 14 bolts, as I do not have much knowledge on them. I've read their Bible, but even that info hasn't helped me figure out which axle would be the best choice.

I have a 9.5" SF axle apart in the garage. Has G80, 3.73, disc brakes.
Pros: I have it. Cheap to put together. Fits the spring perches.
Cons: Not too excited about using a SF for the strip. Possible (probable?) durability issues.

I would much rather use a 10.5" FF axle, but the big question is, which one?
Would one of the older axles ('86-2000) have the same spring perch width as the 1/2 ton in order to bolt right in or do I have to find one from a NBS (99-up) 2500 truck? Trying to stay with the 3.73 gears and disc brakes.
Pros: Cheap. Detroits are dirt cheap, too. Strong. Lots of aftermarket.
Cons: Have to spend extra on Detroit and disc brakes (unless using NBS axle) but what-can-ya-do?

BTW, are the axles out of the 2500 Savana vans compatible with the pickups or are they a different width? I keep seeing 12-bolt versions of the 10.5" and wonder if that would be another possibility, too.



Any advice you can give would be very appreciated.

 

[07bluelbz]

I can tell you from personal experience that the SF 9.5" is very stout. Had one with welded spider gears in my rock crawler with 4.56 gears and 36" tires and never had issues.I don't think the spring perches are the same from 86-00 to 99 and up. Van rear ends from my experience were a tad bit wider iirc.

 

[Chevy1925]

Stay with the 9.5" SF, specially if it's 6 lug and your staying 6 lug on the front. Can't remember if you swapped to 8 lug up front or not

 

[TheBac]

Truck is 8-lug all around. Figured that out eariler this year.

You guys are sure a 9.5 can handle the torque? With slicks? I really dont want to pop the rear on the first boosted launch.

I'd probably add one of these: http://www.taperformance.com/proddetail.asp?prod=TA_1803
but what else can I do to increase the 9.5s durability?

 

[Chevy1925]

Your light which really helps. If you go 10.5, your gunna have to look at 2001nbs and up trucks to keep disc brake and direct swap under the truck. If your worried, that's what I'd look for

 

[thunder550]

Tom, I didn't like my 3.73's, it was too much gear for the light weight truck and small tires. I swapped to 3.42's, and may eventually go to 3.23's depending on how the truck feels after building the trans. I know you have different goals for the truck, just wanted to share my experience.

Will you be launching with slicks? Foot brake or trans brake?

 

[TheBac]

I figure I'm going to run a 12.0-16 or 13.0-16 slick, both of which are over 31" tall.
If I were running the 390/40/17 drag radials (29" tall), then the 3.42s would make better sense.

Foot brake to start. Will have to add line lock kit to truck.
I actually have zero experience with a trans brake.

 

[Vrabel]

If you want to go on a road trip, I got a rear from my 01 complete.

 

[thunder550]

I figure I'm going to run a 12.0-16 or 13.0-16 slick, both of which are over 31" tall.
If I were running the 390/40/17 drag radials (29" tall), then the 3.42s would make better sense.

Foot brake to start. Will have to add line lock kit to truck.
I actually have zero experience with a trans brake.

:thumb: tire size calculator says my 275/55R20's are 31.9" tall

 

[THEFERMANATOR]

I know BIGLEY runs a 6 lug 9.5" rear axle in his 88 DURAMAX swapped truck, and was dyno'ing well north of 600HP(I think it was 648 last vid I saw) through his, as well as running it at the track. If your already 8 lug, then I would look for a 10.5" rear diff myself. The 9.5" will do it, but since you don't have to go with custom hubs why not step up to the 10.5" to begin wth. I think you lose a few gear ratio options with the 10.5" VS 9.5", but yu gain ALOT in strength with the full floating hubs, and 3 bearing pinion support system. Only downside is you don't have as many diff options with the 10.5" rear axle. I wish they would make a TORSEN style for one as the factory G80 in them is pretty weak, and a detroit isn't ideal for DD use.

 

[JoshH]

Have you thought about building a 9" for it? I know it probably isn't the cheapest, but it may be the best.

 

[TheBac]

So, where would be a good place to get a deal on a 9.5" Detroit? :hehe: No....seriously. Looks like $580 is about the least expensive I've found so far.

I think I'll call Merchant and see if he'd like to trade that 261 Tcase I have for the labor to set this axle up.

 

[Chevy1925]

Lincoln lock that bitch

 

[duramaxzak]

http://m.ebay.com/itm/221480742890?nav=SEARCH

 

[1pieceatatime]

Have you thought about building a 9" for it? I know it probably isn't the cheapest, but it may be the best.

You think a 9" is that much stronger than a 9.5? Dollar for dollar built with apples to apples parts that is.

Are guys running detroits on the drag strip? I would think it would be jerky.

 

[JoshH]

You think a 9" is that much stronger than a 9.5? Dollar for dollar built with apples to apples parts that is.

Are guys running detroits on the drag strip? I would think it would be jerky.

I don't think it's any stronger in stock form, but the aftermarket is way better. From what I've seen, there isn't much aftermarket support for 9.5" 14 bolt axles. My biggest problem with the 9.5" in a serious drag racing application is the c-clip semi-float axles.

 

[1pieceatatime]

I don't think it's any stronger in stock form, but the aftermarket is way better. From what I've seen, there isn't much aftermarket support for 9.5" 14 bolt axles. My biggest problem with the 9.5" in a serious drag racing application is the c-clip semi-float axles.

Hard to compare anything to the 9" in terms of aftermarket.

I'm just thinking the 9.5 is a little oversized for the weight of rig so it should fair well and be less parasitic than a bigger full floater. AND he's already got it.

 

[Chevy1925]

Are guys running detroits on the drag strip? I would think it would be jerky.

if they were jerky, you wouldnt see rock crawler guys using them everywhere

 

[JoshH]

Hard to compare anything to the 9" in terms of aftermarket.

I'm just thinking the 9.5 is a little oversized for the weight of rig so it should fair well and be less parasitic than a bigger full floater. AND he's already got it.

That's all I was getting at. The Ford 9" has the ability to grow with the truck whereas the 9.5" 14 bolt is pretty much at it's max potential already. The fact that the 9" is probably a lot lighter is another added bonus.

 

[1pieceatatime]

if they were jerky, you wouldnt see rock crawler guys using them everywhere

Are you really telling me a Detroit isn't jerky?