28 or 30 spline axles?

[HouTX87]

Planning some rear end upgrades. Car is currently mid 11s. Goal is eventually mid 10s. Rear is stock g80 34k miles with no issues.
Should i upgrade to 30 spline axles and new eaton posi or just upgrade to new 28 spline axles and add a girdle? Is it worth the expense to upgrade to 30 spline at this level?

 

[dank GN]

you would have to upgrade the differential if you want to go to 30 spline axels fyi

 

[dank GN]

I went with a Eaton true trac 30 spline moser axels and a C clip eliminator kit as well as a TA cover . I welded the axel tubes while it was out . Truthfully installing the diff sucked and prob won’t do another one . You have to shim it correctly so you have the right pattern on the ring gear ect . It just took awhile to get it in and correct

 

[HouTX87]

you would have to upgrade the differential if you want to go to 30 spline axels fyi

Yes i know. Thats my question. Is it worth the extra $500 for the eaton 30 spline posi? From my experience it would be an easy swap if shims can be reused.
I may just get the moser 28 spline axles for now. That $500 would buy a drveshaft upgrade. I dont want to do c clip eliminators. 99% street car,

 

[Nick Micale]

Yes i know. Thats my question. Is it worth the extra $500 for the eaton 30 spline posi? From my experience it would be an easy swap if shims can be reused.
I may just get the moser 28 spline axles for now. That $500 would buy a drveshaft upgrade. I dont want to do c clip eliminators. 99% street car,

My opinion is the upgrade the driveshaft/U-joints before the axles.

Unless you have great traction and lots of track time, upgrade with Moser 28 spline would also be a good choice.

With lots of track time and good traction, you will find the ring and pinion is the weak link in the rear end.

The TE-44 turbo will not give you wheel-lifting launches on the street or strip to abuse your plan.

 

[HouTX87]

Thanks

 

[HouTX87]

My opinion is the upgrade the driveshaft/U-joints before the axles.

Unless you have great traction and lots of track time, upgrade with Moser 28 spline would also be a good choice.

With lots of track time and good traction, you will find the ring and pinion is the weak link in the rear end.

The TE-44 turbo will not give you wheel-lifting launches on the street or strip to abuse your plan.

Nick, I'm going to get an estimate on having a driveshaft built locally. Would you recommend 3" or 3.5"? Sonnax slip yoke and 1350 yokes and ujoints? Anything specific? Thanks.

 

[ttypewhite]

If you are looking to put in a new rear end, buy a Eaton carrier for 28 spline. That will strengthen your rear end situation. If you want to upgrade to 30 spline down the road you don't have to buy another carrier , you just need to buy and swap out the 28 spline side gears for 30 spline on the carrier and upgrade to 30 spline axles.

 

[HouTX87]

If you are looking to put in a new rear end, buy a Eaton carrier for 28 spline. That will strengthen your rear end situation. If you want to upgrade to 30 spline down the road you don't have to buy another carrier , you just need to buy and swap out the 28 spline side gears for 30 spline on the carrier and upgrade to 30 spline axles.

So youre suggesting to upgrade just the carrier and leave stock axles?

 

[HouTX87]

My stock carrier is still in good shape. Wasnt stock made by eaton? I dont mind doing axles and carrier at the same time to switch to 30 spline. Looking for the best route on about $900. Nick suggested upgrading the axles and driveshaft. Cost is similar either way.

 

[ttypewhite]

So youre suggesting to upgrade just the carrier and leave stock axles?

Rome wasn't built in a day. Spread the money out imo. Get the carrier and a good drive shaft for the time being. I didn't change my axles until it was a 10 second car. When time and money spares, do it later and it's less of a hit on your pocket.

 

[HouTX87]

Rome wasn't built in a day. Spread the money out imo. Get the carrier and a good drive shaft for the time being. I didn't change my axles until it was a 10 second car. When time and money spares, do it later and it's less of a hit on your pocket.

Are you suggesting that the carrier is the weakest link? I was thinking axles, ring and pinion, u-joints. I appreciate everyones input.

 

[ttypewhite]

I don't think you're at that level to worry about your axles, but the fact that you want to start addressing it is great. What I'm suggesting is just a start, down the road you can save your money and finish it with axles and imo C-clip eliminators as that is not a costly expense later. But ultimately it's your decision. There is no right or wrong way to skin a cat if you're end goal is to eventually do it all at some point .

 

[Boost231]

IMOP, order a new drive shaft with 1350 yokes. Changes axles out to aftermarket 28s and out a 1350 pinion yoke on it and call it good for awhile

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[HouTX87]

IMOP, order a new drive shaft with 1350 yokes. Changes axles out to aftermarket 28s and out a 1350 pinion yoke on it and call it good for awhile

Sent from my SM-G935T using Tapatalk

This is exactly what I was thinking earlier today after Nicks input. Like I said, I appreciate everyone's input.

 

[GNVAIR]

The stock positraction carriers are VERY strong. Actually it is very rare to see a Buick break the axles or carrier. But anything is possible. If you are launching with a trans brake then axles and carrier at the same time would be wise. Do the 30 spline at that time. I do agree with Nick. The driveshaft and u joints are the weak spot in the stock drive line.

 

[Undercover87T]

I've run mid 10's off the foot brake so far with a custom 3in driveshaft, 1350 joints, rebuilt stock posi, 28 spline axles and a TA girdle cover. Have yet to use the trans brake which makes me wonder how the stock carrier/ring & pinion will hold up. Only get to the track once a year if I'm lucky.

 

[bad V6]

For what it's worth, I upgraded to the Moser 28 spline axles years ago. Didn't have any issues until the car was running mid 10's consistently on a sticky track. A spider gear came apart and took out the ring and pinion, driveshaft yoke (twisted), and the transmission output shaft (twisted) and input shaft (broke). Then I upgraded to a full billet tranny and 30 spline Eaton and Moser axles.