axle questions, how does 8.25 compare with dana 35, 44 and 60 axles [Archive] - NAXJA Forums -::- North American XJ Association

Eagle

June 2nd, 2004, 18:05

The early (through 1996) 8.25 has 27-spline axles that are the same size and spline count as a Dana 35. The housing and ring gear are larger and beefier than the Dana 35, but the shafts themselves are a toss-up.

The '97 and newer 8.25 has larger 29-spline shafts that are nearly as strong as the 30-spline Dana 44 shafts. The pinion on the 8.25 is lower than the Dana 44, though, which makes it more prone to drive shaft-induced vibrations. Otherwise, it's approximately equal in strength to a Dana 44.

Which means it isn't close to being equal to a Dana 60.

June 2nd, 2004, 18:43

While the 29 spline may be equal in strength to a 44 the downfall would be C-clips to retain the axles.

The axle tubes are also way beefier than a D35 or D44.

OregonXJ

June 2nd, 2004, 20:36

ya the housing itself is pretty strong.and with the 29spline axles it is a pretty tough unit but the c-clips are a problem.

very interesting sjx40250 i have not heard that before.i think i need one of those rainbows over my head that says the more you know.lol

Imjosh

June 2nd, 2004, 21:02

I have a welded 8.25 with 33's and i pretty much give it 5 kinds hell and it doen'st complain much (tires sure do though)

Kejtar

June 2nd, 2004, 21:31

I know of a jeep mechanic of 17 years who claims the spider gears are the week link... worse than the d35C

I remember reading something about someone mentioning that and it seemed to be somewhat unsubstantiated. IIRC for one the mechanic dealt with street driven rigs primarily. ALso if the spiders are a weak link..... that gives you an even better excuse to lock it up :) I was happy with my 29 8.25 and LS then later NoSlip and the only beef I had with it was that big fat lip on the bottom and maybe the fact that it's c-clipped with 4.56 gearing max.

sjx40250

June 2nd, 2004, 23:47

Well, I was surprised to hear it from him after all the statements made on this forum! I can not argue with his experience, however. He did work on, primarily, street rigs. Today he does have a clientele that includes off-roaders.

So should I add fuel to the fire? He also stated that he has repaired more 231's than 242's! My suspicion is that most of the 231’s were behind 5 speeds. There are more 231's on the road and trail than 242's.

I am simply relaying his statements and believe he has integrity, IMHO. I have no reason to discount any of the experiences on this forum either, so it comes down to specifications and which have the most value for the application. In the end, we each get to make our own choices with the the information available and the value we put on each one. That statment is not restricted to just to our rigs. It is what makes this country great and unique!

OregonXJ

June 3rd, 2004, 00:43

I totaly agree with you.Also i just niticed you are from oregon so i hope to see you on the trail some time.

Boris T

June 3rd, 2004, 04:46

Well after owning a 94 Dakota Reg Cab short bed sporting a 5.2 Mag, 46RH auto and 8.25" with 3.55 and limited slip for 8 years I am impressed with it's durablility. Maybe trails are different but there were many times I misbehaved with one foot on the brake and one on the gas. After I added the MP headers, MP computer, M1 2 bbl intake that truck would move out. Heck, it was fun to light them up with a car on a trailer behind it. :dunno:

may guys running 300+ HP and 325fl/lbs of torque thru the 8.25 in the Dakota world without probs. More than 350HP then things get ugly :repair:

tjl1388

June 3rd, 2004, 04:53

anybody have any pics of a welded 8.25, what does that strengthen, and is there any way to convert to the 29 splines?

Kejtar

June 3rd, 2004, 06:23

Well the 231 repair I can understand because probably he had whole bunch of people drive in 4wd in a 231 equiped on a street. So you really have to look at the whole picture before you make a decision about what some piece of information means.
Btw, what does having a 231 behind a 5 speed have to do with breakage?

Well, I was surprised to hear it from him after all the statements made on this forum! I can not argue with his experience, however. He did work on, primarily, street rigs. Today he does have a clientele that includes off-roaders.
So should I add fuel to the fire? He also stated that he has repaired more 231's than 242's! My suspicion is that most of the 231’s were behind 5 speeds. There are more 231's on the road and trail than 242's.
I am simply relaying his statements and believe he has integrity, IMHO. I have no reason to discount any of the experiences on this forum either, so it comes down to specifications and which have the most value for the application. In the end, we each get to make our own choices with the the information available and the value we put on each one. That statment is not restricted to just to our rigs. It is what makes this country great and unique!

CRASH

June 3rd, 2004, 06:49

While the 29 spline may be equal in strength to a 44 the downfall would be C-clips to retain the axles.

The axle tubes are also way beefier than a D35 or D44.

Can you explain to me how method of axle retention has anything to do with axle shaft strength?

CRASH

Tom R.

June 3rd, 2004, 08:09

Who says the 29-spline shafts are as or nearly as strong as the D44 shafts? It's tiring to "hear" people repeat what they heard, not what they know. Look for yourself at the shaft diameter of the D35, 27 and 29-spline 8.25, and the D44. The size of the 29-spline is closer in size to the D35 than it is to the D44. Perhaps then we should be saying it's "as strong as the D35" instead of the D44. :confused:

Tom

Drewlee77

June 3rd, 2004, 10:41

8.25" Ring Gear = 8.25"
D44 Ring Gear = 8.5" (+3%)
D35 Ring Gear = 7.5" (-9%)

8.25" Axle Shaft Dia. = 1.21"
D44 Axle Shaft Dia. = 1.31" (+8%)
D35 Axle Shaft Dia. = 1.16" (-4%)

8.25 Axle Spline Count = 29
D44 Axle Spline Count = 30 (+3%)
D35 Axle Spline Count = 27 (-6%)

8.25 Axle Tube Dia. = 3"
D44 Axle Tube Dia. = 2.76-2.72" (-8-9%)
D35 Axle Tube Dia. = 2.64-2.48" (-12-17%)

EDIT: Percentages are rounded off. No figures yet for Axle Tube Thickness, nor any numbers concerning pinion strength.

Nay

June 3rd, 2004, 10:45

Let's try some actual stats:

The 29 spline 8.25 axles are 1.21" diameter. 30 spline D44 axles are 1.30 diameter. You can find axle shaft strength ratings on Moser's site (at least last time I checked). An alloy 8.25 axle would be close in strength to a stock 44. Alloys make excellent sense for an 8.25. Keep your stock shafts as spares.

The 3" diameter 8.25 housing appears not to suffer the housing flex that plagues D35's, and hence we don't hear much about busting 8.25 shafts, especially not the 29 spline.

The 8.25 pinion is 1.675" with 27 splines, compared to something like 1.35" for the D44 (and 23 spline???)...much beefier. The 8.25 R&P should be comparable in strength to the D44.

The 44 is a better axle than the 8.25 in every way, IMO, but there is no reason to get rid of an 8.25 for 33" tires unless you have constant gear noise problems like I did. The axle shafts are identical side to side, which is nice for spare parts, and disc brakes take away some of the c-clip retention concerns.

Just get a full carrier replacement diff, and you'll have removed what I have also heard is the major weak link in the 8.25 (carrier/spider gears).

Nay

ChuckD

June 3rd, 2004, 10:47

You have to take in account the housing. That is the D35's weakest point, not the shafts. My locked D35 held up pretty well with my 33's. So therefore even though the 29 spline shafts are smaller, it's the tubes and the housing that push it closer to the D44 level of strength.

FWIW, 8.25's like D35's are worthless unless you get them rather cheap. ;)

xjhm

June 3rd, 2004, 11:12

anybody have any pics of a welded 8.25, what does that strengthen, and is there any way to convert to the 29 splines?
they weld the spider gears together to lock the rear axles together...
the best conversion to 29 spline is to buy a no-slip for a 29 spline and buy two 29 spline axles...or three and have a spare ....

RichP

June 3rd, 2004, 11:18

they weld the spider gears together to lock the rear axles together...
the best conversion to 29 spline is to buy a no-slip for a 29 spline and buy two 29 spline axles...or three and have a spare ....

Yea, thats the best way, when I had the auburn put in they don't reuse the carrier, just the ring gear and axles.

Kejtar

June 3rd, 2004, 11:27

they weld the spider gears together to lock the rear axles together...
the best conversion to 29 spline is to buy a no-slip for a 29 spline and buy two 29 spline axles...or three and have a spare ....

You also would need a carrier for that conversion... and in that case, why not get a detroit?

DaffyXJ

June 3rd, 2004, 12:32

I just took a few measurements from both a Corp 8.25 and D-44 axle shaft. There is a difference.

The axle diameter at the bearing is:
Corp - 1.6 "
D-44 - 1.55"

The shafts taper down for a couple inches to
Corp - 1.5"
D-44 - 1.44"

The main length of the shaft is
Corp - 1.3
D-44 - 1.28

The axles taper again at the spline end:
Corp - 1.15 for a length of 6 inches and has 29 splines
D-44 - 1.24 for a length of 2.8 inches an has 30 splines

The weakest link is the length of the taper at the spline end of the Corp 8.25 shafts. Not saying they are way inferior, but when you couple the C clip with the thinner axle shaft, I think one has to agree the D-44 axle shafts are a lower risk.

I ran the Corp with 33's for a while and had no problems. When I graduated to more difficult obstacles and heavier wheels, I opted for a 44.

Derik

CRASH

June 3rd, 2004, 12:47

but when you couple the C clip with the thinner axle shaft

The only time a C-clip comes into play is once you've already broken a shaft. At that point you can drive a little bit further on a regular Set 10 bearing before having to change a shaft. Other than that, don't let C-clips scare you.

CRASH

ZachMan

June 3rd, 2004, 15:28

HP 9" is the way.

CRASH

June 3rd, 2004, 15:29

HP 9" is the way.

If you run smaller than 35's.....

CRASH

Jes

June 3rd, 2004, 15:32

Even if you run 35s...
http://fototime.com/{F9B4F2D8-00CD-11D7-9867-00C0F05AE12E}/picture.JPG
...31 spline shafts can break.

CRASH

June 3rd, 2004, 15:34

Is that SeanP......dare I say it.....4 wheeling?

CRASH

Jes

June 3rd, 2004, 15:36

100 yards into Jackhammer, or was it 100 feet?
That might be the last time he wheeled.

ZachMan

June 3rd, 2004, 15:49

If you run smaller than 35's.....

CRASH

Not really, with 35 spline shafts it would be really strong, atleast in my area. (Tellico, GrayRock, etc.) Don't go by Currie who says 35" tire max with 500hp. LOL, yeah I got 190 at the crank, figure most on here have around that also. SO 37s should be just fine. (Yeah I know anything can be broken)

Jes,

got any more pics of SeanP's XJ on the trail, since he built it up (more).

CRASH

June 3rd, 2004, 15:54

You don't need 35 spline shafts with a hipinion 9", as it has been shown that the gearset is likely the weak link with 31 spline shafts.

You are asking a reverse rotation 8.8 gearset to do rear axle duties, and they are just not designed for that. Same with a reverse spiral 44. They are driving on the weak side of the gearset when used in this application.

Even a standard spiral 44 and 8.8 gearset are marginal for 36" tires out West. Hell, Goatman broke a 44 gearset with 33's.

CRASH