500+ HP rear Axles?

Indeed I realize. Given the amount of info it seemed reasonable to keep it in this thread. The main contributor was active about 6 months ago (I did check before posting!). If no one chimes in I plan to get to the bottom of these questions and post the answers myself since the info is missing from this thread and otherwise virtually internet-unique AFAICT.
 
Forget his user name at the moment... but there was a member on here that used an LS Gen 1 diff and stuffed an 8.8 posi center section in it.

He custom fabbed some brackets to mount the diff... and used stock Gen 1 cv axleshafts. IIRC... he was running around 400-450 HP.
 
arsenix said:
I am bumping this thread to ask a few questions! I am trying to replicate what you have done here. I am also trying to make custom beefy axles on a budget. Few seem to have tried this and there is little information online!

Do you have measurements or specs of the Explorer "37 spline" CV axles? I can't find the specs on these anywhere. I believe they must be a different pitch than the standard axle splines (which are 24 spline typically). If you have the major diameter I think I can figure it out. Maybe these CV axles use a metric pitch?

Were the front inboard CVs off the F150/Explorer different than the rear ones? I wasn't clear if you also looked at the rear axles. I was presuming I could try to use rear inboard Explorer CV's, but maybe these are different in some way?

So did you end up machining the differential housing to take the larger truck sized seal? Actually it sounds like you managed to find a special seal that would fit in the axle housing but had the right ID? That is brilliant! I have a lathe and was presuming I could just turn down the seal diameter but this is easy peasy!


Really appreciate all your work on this. We think alike! Hope you are still on the forum after 7 years :) Looks like you signed in earlier in the year at least!
Click to expand...


Yes I am still around. I did that long enough ago that I don't remember the details. I should have all my notes and details in an Excel file on a back-up drive.

Off the top of my noggin, I purchased a Torsen 8.8 LSD that used the larger spline hubs. I did open up the housing to accept a larger seal. (I do have spares and P/N for the seal somewhere.) I recall spending a lot of time finding a seal that would work, then getting the exact dimensional details, and then machining the housing to accept the seal.
I don't recall who made my custom axles. I changed my rear end assembly to use Corvette spindles, so I ended up 3D modeling the complete custom suspension in order to determine the axle length. Before you get excited about, the possability of getting your hands on the models, since I did them after hours at work, our company security system prevented me from downloading the files. (They let me use their Solidworks for my own projects, but I couldn't take/keep the models.) Therfore, I made parts from paper drawings rather than IGES files.
 
tijoe said:
90+ percent sure that these are the seals I used.

451817 by FEDERAL MOGUL-NATIONAL SEALS - Oil Seal

Other details will have to wait, until I can find time to dig out my back-up drives and find the folder that has all the information on that project.
Click to expand...

Interesting! Although it would be easy enough for me to turn down the seal surface I think those OEM stubs tend to be just surface hardened... so I am a little concerned they may break where the seal was. That seal is a brilliant find. Just need to open up the diff slightly. The Explorer seals are beastly and would never fit.

The main thing I can't find is the specs on the explorer spline. For some reason except only a few isolated types (like the Porsche CV's popular with the sand rail folks), halfshaft CVs just aren't well documented.

Thanks!
 
Back when I had my axles made, the splines on the explorer hub were a common size that was in their of tooling selection. The C4 corvette spline was a problem and the shop that made the axles had to order tooling to be able to make the splines. I have probably 10-15 different axles I measured and ran calculations on to find which one would work best. I'll have to search for my files in order to refresh my memory regarding dimensions and who made the axles.

I found nothing regarding dimensions of CV joints. Did discover that the housings are almost all produced in around 5 different sizes, then are machined per the specific application.

You could go the route and have $2,500 to $3,000 custom ones fabricated to your specification and HP rating.
 
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Old thread but I was asking if anybody ever took the rear axles out of the rear end will the diff fluid spill out or no
thanks
 
04_Sport_LS said:
If the diff is overfilled... yes.

If you have the back end of the car lower than the front end... most likely.

The diff DOES have a drain plug.
Click to expand...
Ok thx
I was planning on replacing both the axles due to play and noise. The boots were torn up just asking if I new seals are required or can I reuse them?
 
50/50 chance the seals will hold up for a while... as long as they are not swollen or split.

Ask yourself how long the new axles will hold up... then ask yourself how long the used seals will hold up.

By the time you get the axles out of the rear knuckles... you will ask yourself if you want to do that again... just to replace leaking seals. :-/
 
Actually... I lied. The diff has a fill plug. You need a suction gun to drain the diff.

Replace fluid with Mobile 1 synthetic. 75w 90... or 75w140... depending on your climate.
 
If you replace the seals... buy OEM. You will need a seal driver kit (from HF) to install them.

Bearing race driver kit will not work. The new seals will/may get damaged.
 
JustALs said:
Old thread but I was asking if anybody ever took the rear axles out of the rear end will the diff fluid spill out or no
thanks
Click to expand...
I am confused by this question and the answers. They make sense for a solid axle, but not so much for IRS. Is this not about an LS?
 
Maybe this wasn't the best place to ask his questions... but what he is asking makes sense to me.

He is wanting to replace worn out rear axle shafts... with new ones.

I answered his questions with true statements.
 
Maybe I made a bad assumption about the seal design. (shrug) I didn't feel like going out and crawling under my LS to verify.

Gotta get the axle shafts out of the rear knuckle to replace them (which is what he is wanting to do)... and I suggested replacing the seals (which he wasn't sure he wanted to do).

Fluid could leak out..
depending on factors mentioned.
 
Yeah this wasnt the place to ask but im asking for a Ls... 'thought this post was in lincoln ls category

I got new bearrings in the hubs last few months so it will get out the hub side with no much effort .
never really touched rear ends only engines but if it will spill out by removing the axles , should I just drain the rear end first so theres less mess before pulling ? Since I wanted to drain and re fill
Was Asking this because maybe I should check the plug on my rear end isnt seized first to make sure I can fill it back after . Just by looking at it quickly I only seen a bolt with a square in it is that the fill?
And @04_Sport_LS is this what I need for the seals Amazon product ASIN B01FEDVWPO
 
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JustALs said:
should I just drain the rear end first so theres less mess before pulling ?
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Yup. Best method

JustALs said:
Was Asking this because maybe I should check the plug on my rear end isnt seized first to make sure I can fill it back after . Just by looking at it quickly I only seen a bolt with a square in it is that the fill?
Click to expand...

It's a plug with an inverted 3/8" square. You use a 3/8" ratchet (and extension if necessary) to pull the plug. Again... you will need a siphon/suction gun to drain the diff. Level car when/before refilling the diff.
 
04_Sport_LS said:
Yup. Best method



It's a plug with an inverted 3/8" square. You use a 3/8" ratchet (and extension if necessary) to pull the plug. Again... you will need a siphon/suction gun to drain the diff. Level car when/before refilling the diff.
Click to expand...
Sounds good thanks alot for the info !
 
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