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Discussion Starter · #1 ·
Hello,

I would like to know how a 31 spline Ford 8.8 rear axle from a 98 or newer Ford Explorer compares with the strength of Super 35 rear axle in a Jeep TJ application. I am new to this site and I have been wanting to discuss this topic with others, have tried posting on other threads twice, but have apparently not found the appropriate thread for it as of yet. So, I started my own. I would just like to know what some of your opinions are on this topic. Please keep your responses informative, not argumentative. I would like this thread to be useful for those who might be considering an 8.8 swap or investing in thier current Dana 35 with a Super 35 kit.

I'll start...I have been trying to find some kind of chart that compares axle shaft strength between various axles, such as the 30 spline Super 35 and the 31 spline 8.8, Dana 60, Dana 44, etc. Does anyone know of such a chart?

Thank You:)
 

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!

NOt even Close.........Building a Dana 35 is like polishing a terd......8.8 is like 120% stronger than the D35.i'm doing the swap on my 92 XJ in a few days.plus the 8.8 tubes are much bigger and thicker..just a much more robust axle and you get free disc brakes too!! only bad thing is that the 8.8 is 1" narrower that the D35 but some spiudertrax wheel spacers will fix that... just make sure to weld the center section to the tubes if you do go this route...BTW Ruff Stuff specialties has an 8.8 easy swap kit for like $120...I hope this helps
 

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8.8

HINT*(GOOGLE.COM)
here is some good info

http://www.jedi.com/obiwan/jeep/ford88.html

has some strength specs in here
http://www.jeepsunlimited.com/forums/showthread.php?t=674123

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Axle shaft Strength and output torque rating by Warn and 4 Wheeler

The axle shaft strength tested by Warn Ind:
F8.8= 6,500 (lb. ft.)
D44= 4,600-5,000 (lb. ft.)
D35C= 4,000-4,300 (lb. ft.)

COT: Continuous output torque rating
MOT: Maximum output torque rating

(Numbers from January edition of Fourwheeler, page 60.)
Dana 35 rear axle COT: 870 MOT: 3480
Dana 44 rear axle COT: 1100 MOT: 4460
Ford 8.8 28spline COT: 1250 MOT: 4600
Ford 8.8 31spline COT: 1360 MOT: 5100
Dana60 semifloat COT: 1500 MOT: 5500]
 

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Discussion Starter · #5 ·
(Numbers from January edition of Fourwheeler, page 60.)
Dana 35 rear axle COT: 870 MOT: 3480
Dana 44 rear axle COT: 1100 MOT: 4460
Ford 8.8 28spline COT: 1250 MOT: 4600
Ford 8.8 31spline COT: 1360 MOT: 5100
Dana60 semifloat COT: 1500 MOT: 5500]
Thanks for this, but I have seen this one before. Is there a comparison chart out there that compares the "Super" Dana 35 shafts to the others listed above? That is what I can't seem to find using Google.com What is the COT and MOT numbers for a 30 spline Super Dana 35 shaft?

Thanks.
 

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Discussion Starter · #6 ·
There are postings of axle shaft failure torque rating. I won't repost them here because it doesn't represent what were discussing accurately.
where is this comparison of axle shaft failure torque rating that includes the Super Dana 35? The above link did provide alot of useful info on the stats of the axles, but this information was not in that thread. Anyone have a link to that comparo? Does a Super 35 shaft equal strength of a Dana 44, 8.8, or better? I don't know and would some info on just how strong they are.

Also, any chart that throws the shaft from the Super 8.8 in the comparo with the other axles would be some good information.

Thanks
 

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NOt even Close.........Building a Dana 35 is like polishing a terd......8.8 is like 120% stronger than the D35.i'm doing the swap on my 92 XJ in a few days.plus the 8.8 tubes are much bigger and thicker..just a much more robust axle and you get free disc brakes too!! only bad thing is that the 8.8 is 1" narrower that the D35 but some spiudertrax wheel spacers will fix that... just make sure to weld the center section to the tubes if you do go this route...BTW Ruff Stuff specialties has an 8.8 easy swap kit for like $120...I hope this helps
too much in this post is factually incorrect
read up;
http://www.jeepforum.com/forum/showthread.php?t=583412
if you don't believe me, cross check the facts;
http://www.jeepsunlimited.com/forums/showthread.php?t=674123

Axle shaft Strength and output torque rating by Warn and 4 Wheeler

The axle shaft strength tested by Warn Ind:
F8.8= 6,500 (lb. ft.)
D44= 4,600-5,000 (lb. ft.)
D35C= 4,000-4,300 (lb. ft.)

(Numbers from January edition of Fourwheeler, page 60.)
Dana 35 rear axle COT: 870 MOT: 3480
Dana 44 rear axle COT: 1100 MOT: 4460
Ford 8.8 28spline COT: 1250 MOT: 4600
Ford 8.8 31spline COT: 1360 MOT: 5100
Dana60 semifloat COT: 1500 MOT: 5500]
These number are misleading.
They compare stock shafts

where is this comparison of axle shaft failure torque rating that includes the Super Dana 35? The above link did provide alot of useful info on the stats of the axles, but this information was not in that thread. Anyone have a link to that comparo? Does a Super 35 shaft equal strength of a Dana 44, 8.8, or better? I don't know and would some info on just how strong they are.

Also, any chart that throws the shaft from the Super 8.8 in the comparo with the other axles would be some good information.

Thanks
I think the magazines are afraid to perform this test.

A reasonable assumption of S35 shaft strength would be; equal to a D44 shaft made from 4130.
This would logically make it stronger than a regular 44 shaft.

Also keep in mind. The strength of an axle assembly is not based on just the shaft strength.
 

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I've never seen a chart of breaking strength of a super axle. But they DO say that a super axle is 30 to 35% stronger. So just take those numbers above and add 35% to them. The super 88 does not include a locker and eliminates the c-clips, and adds 3/4 ton bearings.
I put a 30/30(AlloyUSA's version of a super 30) in a few years ago after a streak of axle issues, no issues sense.
I am convinced in super axles. They are worth having(just don't spend a lot on a dana 35).
 

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Discussion Starter · #9 ·
thank you for contributing on this post Never Monday. I did not intend to anger anyone when I posted on your thread regarding the Super 35/D44/8.8.

just new to the site and have been looking for a place to start an healthy discussion regarding this subject.
 

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thank you for contributing on this post Never Monday. I did not intend to anger anyone when I posted on your thread regarding the Super 35/D44/8.8.

just new to the site and have been looking for a place to start an healthy discussion regarding this subject.
NP, I'm trying to keep that thread to the facts for people looking for a different axle.

this will be a good one for hashing out the opinion...and I have some
 

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Discussion Starter · #11 ·
Never Monday,

As I am sure you have realized, I have the 8.8 in my TJ. I'm not saying its better than anything else. Its just what I chose over a super 35 kit or dana 44 swap. You have mentioned on the fact that there are some common misconceptions about the 8.8 as a good swap canidate, but have not elaborated as of yet because the current thread was not the place to. I was just curious about your perspective. There may be something that I am not aware of. Please elaborate about the disadvantages of the 8.8. I already know about how its a custom set-up (not bolt-in), c-clip axle. But what else? This in not me being sarcastic, I am wanting to learn more on the subject, and I like the discussion.

Thanks
 

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C-clip shafts
3 welds hold the tubes to the center (same as 35. 44 has 6)
increased tube dia = decreased ground clearance
increased casting = decreased ground clearance
none are bolt in for a TJ and require welding
offset chunk; not a big deal but won't work with a GenRight strech tank
thin cover
thiner tubes than a 35 or 44 (although the strength is about equal due to dia)
narrower track
no locker (S35 has a locker, R44 has a locker)

all can be over come. I just don't see enough strength gain to go through all the work. I do see the 8.8 as a viable, readily available axle to convert for a TJ.
 

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IMHO If you're breaking S35's, then why not step up to a shaved 9" semi floater? You're not looking at that much more unless you slap a high pinion third on it.
 

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.8.8 is like 120% stronger than the D35. not a tested and published statistic.

plus the 8.8 tubes are much bigger and thicker..
They are larger in dia, BUT thinner walled. There is rumor of a .250 wall housing. But of the 25 or so samples in a pull a part here all were .187. These were under everything from Mustangs, Explorers, F150 and, Crown Vic's.

just a much more robust axle and you get free disc brakes too!! not on all 8.8's

just make sure to weld the center section to the tubes if you do go this route...If you need to weld the casting to the tubes, how can it be a more robust axle?
answers in red
 

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Originally Posted by Paulio91184
.8.8 is like 120% stronger than the D35. not a tested and published statistic.
Maybe not numbers wise but put 4.10 gears and 33's on a D35 and its a recipe for disaster

plus the 8.8 tubes are much bigger and thicker..
They are larger in dia, BUT thinner walled. There is rumor of a .250 wall housing. But of the 25 or so samples in a pull a part here all were .187. These were under everything from Mustangs, Explorers, F150 and, Crown Vic's...........That i did not know, guess i can't believe everything i hear


just a much more robust axle and you get free disc brakes too!! not on all 8.8's............he said 98 and up so that is what i was refering to

just make sure to weld the center section to the tubes if you do go this route...If you need to weld the casting to the tubes, how can it be a more robust axle?...............You don't really have to weld it but welding the tubes vs building an entire axle like the D35 up just isn't worth it in my opinion


I can weld so for me the 8.8 is just a better option
 

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Ive run 9+ rated trails in colorado with a super 35 with 456 gears 35" tires and have never had a problem. And the use of the saying " you cant polish a turd" is a joke. The super 35 is a good way to go if you dont plan on tires over 35".
 

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Thanks for this, but I have seen this one before. Is there a comparison chart out there that compares the "Super" Dana 35 shafts to the others listed above? That is what I can't seem to find using Google.com What is the COT and MOT numbers for a 30 spline Super Dana 35 shaft?

Thanks.
I'll bet you won't find published info on a Super35. Don't put money into a D35c, its a crap axle, always has been, always will be. You can put all the money you want into it, and its still a crap axle. The housing and tubes will still be thin, the ring gear will still be small, you'll still be limited by gear ratios, and you'll still see housing flex.

So answer your questions...you can calculate the THEORETICAL strength of any solid bar pretty easily (like and axle). Its a typical undergraduate physics & engineering problem dealing with the moment of inertia: http://en.wikipedia.org/wiki/Moment_of_inertia Go figure out the yeild strength of each alloy of steel, then learn some physics and it will take you about 15 minutes to do your calculations.

But, axle shafts are not the only thing contributing to the strength. You've got a lot more factors like:
1. size of the ring gear
2. tube thickness
3. housing thickness
4. housing flex
5. size of pinion gear
6. size of bearings
7. c-clip vs non-clip
8. semi-float vs full-float
9. alloy of metals involved in all of the above

The short answer is simple:
8.8 > D44 > D35c
 

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have not done an axle swap as of yet and have watching and reading all the posts that i can in hopes to one day swapping my Dana 35 for something different. i can see advantages to the S35 upgrade, D44 and the 8.8, all have there pros and cons in their way. i think it is just up to the owner, his budget, skill level and time. also it makes a difference if the jeep is a DD or strictly a trail rig. all the info was very helpful. thanks for all the info and your opinions i will keep watching this thread just to educate myself on all the different options.
 
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