XJ 8.25 vs 44

My son has a 29 spline 8.25 in his 99 XJ with a new Detroit. He found an XJ 44 and bought it. I think the 44 is a stronger axle but is it worth the trouble to buy a new Detroit for it? Pros and cons???? We're going to regear anyway, so that's not the issue. He's running 33" Mickey Thompsons, but wants to go to 35s when we do the long arm install.

Strength differences are little, but with the 44 you can gear deeper than 4.56s. Although rumor has it someone was making 4.88s for the 8.25...

The d44 can gear deeper than the 8.25


The D44 can get CrMo shafts in 30, 33 and 35 spline, where the 8.25 can get 1541 shafts in 29 spline. (this is why i upgraded from 8.25 to d44)

D44 has cheaper locker options (although for detroits the price is similar).

For 33's or less, the 29 spline 8.25 is great, throw some 1541h shafts in with explorer discs and call it done.

If you wanna run 35's, I'd probably build the dana 44.

Dana 44 has WAY more aftermarket support, but word on the street is that they are coming out with 4.88s for the 8.25 soon!!(can anyone confirm??) Since you've already got a detroit in the 8.25, I take it you're probalby already done gearing it. If 4.56s are all you'll need, why bother with something that isn't gonna give you any real strength increase??

That being said, here's what I don't like about the 8.25 (in no particular order):
1) freaking bottom of the pumpkin hangs down low!! That lip is a biatch!! It just doesn't want to slide over rocks like a smooth bottom diff. I guess you could shave the bottom if you wanted though...
2) Not sure how they do with non-stock gears, but the pinions on stock 8.25s LOVE to leak and eventually the pinion bearings go bye bye. Don't know why this is such a problem with these axles??
3) C-clip.
4) Can you find a U-bolt style yoke for these axles?????


If you're already happy with the 8.25s gears and lockers, why spend money on an axle that in stock form (stock axle shafts that is) is comparable in strength?? In terms of throwing discs on them, it would be easier to do to the 8.25 because you don't have to mess with a new retainer plate!

mjma said:

Dana 44 has WAY more aftermarket support, but word on the street is that they are coming out with 4.88s for the 8.25 soon!!(can anyone confirm??)

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I know of two rigs already running them.

mjma said:

.. why bother with something that isn't gonna give you any real strength increase??

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You should read the post above yours.

mjma said:

If you're already happy with the 8.25s gears and lockers, why spend money on an axle that in stock form (stock axle shafts that is) is comparable in strength??

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I agree with this too, but anyone that plans on running 35's needs to plan on not running stock axle shafts either. Alloy 8.25 shafts 'squeeze by' with 35's and don't really hold up as well as a chromoly shaft would.

if you can sell the 8.25 in it's current condition to offset the cost of the locket and regearing the d44 I would say go ahead and set it up, like everyone else said more options and stronger. Really depends on what your budget/long term goal is.

Thanks for the replies. To answer a couple of your questions, no we haven't geared the 8.25, which is a factor in the decision. We are leaning toward 4.10s or 4.56s.

What do you think an 8.25 with a Detroit is worth?

I'm familiar with the 44s aftermarket support and strength. I ran alloys in my old XJ with a 44, 4.56 gears and 37" tires. I ended up breaking the ring gear after a couple hard years of abuse.

Rockon said:

What do you think an 8.25 with a Detroit is worth?

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Not sure about there, but I picked up both my axles (D30 4.10 w/ Detroit trutrack, 8.25 4.10 Detroit locker) for $400. I think it was a pretty good deal.

Rockon said:

Thanks for the replies. To answer a couple of your questions, no we haven't geared the 8.25, which is a factor in the decision. We are leaning toward 4.10s or 4.56s.

What do you think an 8.25 with a Detroit is worth?

I'm familiar with the 44s aftermarket support and strength. I ran alloys in my old XJ with a 44, 4.56 gears and 37" tires. I ended up breaking the ring gear after a couple hard years of abuse.

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Easy answer now, do the 44. If you have to regear anyway you are already going to be buying gears and paying labor to install them sell. Just try and sell the 8.25 for the cost of the detroit for the D44

The strength of the 8.25 has been discussed thoroughly, Ive done lots of research on it because its what i have and wasnt sure if an 8.8 swap would be worth it, but honestly if your running just 35s its fine if you go easy on it. I wouldnt even swap out the shafts, just run it as is with new gears and see how long it lasts, sell taht 44 for $500 and boom you got your gears covered.

The reason not more ppl run the 825 is its not techincally in a "half ton" class, but that doesnt mean it isnt a stout axle. I wouldnt run anything over 35s on it, but 35s is a great setup for that axle if your easy on the pedal. Their "rock crawling" rating is 33s locked 35s unlocked, but that is under ROUGH conditions, if you go easy it should be alright. if you only run rox then you might want to reconsider. But id sell that 44 and save your money till somehting breaks. my 2 cents

emr1101 said:

The reason not more ppl run the 825 is its not techincally in a "half ton" class, but that doesnt mean it isnt a stout axle. I wouldnt run anything over 35s on it, but 35s is a great setup for that axle if your easy on the pedal. Their "rock crawling" rating is 33s locked 35s unlocked, but that is under ROUGH conditions, if you go easy it should be alright. if you only run rox then you might want to reconsider. But id sell that 44 and save your money till somehting breaks. my 2 cents

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That's the attitude I have as well. I asked the same question as the OP back in Nov last year, I had a 29-spline 8.25 with fresh bearings, and a JY XJ D44.
http://www.naxja.org/forum/showthread.php?t=933804

I decided to keep the 8.25, and I'm glad I did. It's a good axle, seems pretty strong, and I don't know of any aftermarket parts that I would want for it that aren't available. Sure, there's no C-clip eliminator kit that I know of, but that's what ZJ disc brakes are for.

!!!1

Chrysler 8.25 - 29 spline, 1.21" diameter shafts, 8.25" ring gear, pinion diameter 1.625", 3" axle tube.

Dana 44 non c-clip - 30 spline, 1.31" diameter shafts, 8.5" ring gear, pinion diameter 1.376", 2.75" axle tube.

jeepme said:

!!!1

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Yep, agree and thanks for the input. I just didn't know much about the 8.25. Appreciate the patience.

I have 4.88 for 8.25 at home, bought them here www.justdifferentials.com same as the ubolt style yoke for the 8.25 -----

In case any one comes across this thread in the future and is wondering...

Dana 44 can go as low as 5.89.

Root Moose said:

In case any one comes across this thread in the future and is wondering...

Dana 44 can go as low as 5.89.

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yup

The 8.25 is a good axle and the aftermarket support is growing for that rearend. I was recently told that someone is making chromo kits for the 8.25 now. That being said the 8.25 is alittle more common and easier to find so I would stick with it and sell the 44. As far as the lip on the bottom build a skid plate and call it done. I am trussing 98 8.25 right now to go under my jeep and going to build a skid for the bottom of the diff.

they chry. 8.25 deserves more respect then it gets. i pounded on mine with 35s, and it never skipped a beat. my friend has run his chry 8.25 on everytire size available between 30-38 and never had a problem. other then being extremely sluggish with stock gears.

so if you think your going to stop at 35s i say go for it.

even though ive never seen one fail, under fairly harsh wheeling, i wouldn't put any money into one. you only have so much aftermarket for the 8.25, and you can only make it so strong. with 44s, and 8.8s you have a wide number of options. if i built an 8.25 i would have needed gears (cant go to 5:13 which my 8.8 has), i would have wanted larger shafts (again cant upgrade any more the 29 spline), and a locker (im a lunchbox guy so both fit this category) and i wanted disk breaks

so for my the 8.25 just didn't do what i needed.

i have the same opinion on a dana 30. its a fairly stout axle...and i have no real problem with one being under my rig, but at the same time, i would go anyfarther then putting a cheap lunchbox locker into it

my combo was a waggy 44 front, and ford 8.8 rear, all in all over building up stock axles ive probably spend about 500 bucks more, but worry about them far less

FWIW, I have seen a full float conversion kit for the ChryCo 8.25.

I forget where and by whom and what the spline count was but I did see it.