What is a spline?

[modelbuilder]

I am trying to figure out if my Grand has a certain type of spline...Chrysler 8.25 29 spline.

Not sure if its in the 05 WK. I looked in the 7,000 page factory manual I have and nothing came up.

 

[Root Moose]

Splines are the long grooves in the end of the axle shaft that engage the spider gears inside the differential. There is nothing external to the axle that will allow you to determine what the spline count is. That said, I'm 99.99% certain all ChryCo 8.25" rear axles switched to 29 spline (from 27) sometime in the mid-late 1990s.

Are you sure what axle you have in your Jeep? Likely it is a ChryCo 8.25" but I'm not up on WKs; did they offer other axles?

 

[FlexdXJ]

I am trying to figure out if my Grand has a certain type of spline...Chrysler 8.25 29 spline.

Not sure if its in the 05 WK. I looked in the 7,000 page factory manual I have and nothing came up.

That is the number of splines used on the axle shafts.I am guessing it would be a 29 spline as they were used in the Cherokee's after '96 replacing the 27 spline. not sure what rear axle a WK would have though.

 

[tdesanto]

I am trying to figure out if my Grand has a certain type of spline...Chrysler 8.25 29 spline.

Not sure if its in the 05 WK. I looked in the 7,000 page factory manual I have and nothing came up.

These are the ridges on the end of an axle shaft. As far as I know, a 29 spline is the number of discrete ridges that it has.

For example, the rear diff in my Montero has 33 splines, the front, 28.

More info here, and here.

 

[SixLug]

*thinking, thinking* Should I tell him what splines are too??? *thinking*

ha ha...jk.:elkgrin:

 

[modelbuilder]

Found out my rear axle is 8.3" and is something called the Corporate...I guess there is no chance it will fit an 8.25" locker right.

 

[SixLug]

Corporate? Hmmm. I thought that was a GM axle...Corporate 12 bolt, 14 bolt, etc??? In any case, no that Chrystler 8.25 locker will not work. Where did you find the information?

 

[modelbuilder]

On this website....

http://www.wkjeeps.com/wk_specs.htm#REARAXLE

 

[SixLug]

ok, and whats your engine? Do you have the elec. limited slip? Do you know your gear ratio? I see nothing on there that says Corporate, but I do see Conventional. Im not sure what that is...maybe thats the Chrysler axle? Another thing you need to do is get on the ground under the Jeep (best place in the world by the way) and look at the markings on the axle...they can tell you a lot. If you need some help, take pics of the symbols and post them here and we can help identify.

 

[ntsqd]

8.25" rounds to 8.3"; Chrysler is 'corporate' to a Jeep. I dunno, I wouldn't give up yet.

 

[SixLug]

I see where youre going with that, but Ive always seen the 8.25 referred to as an 8.25, never as an 8.3.

http://jeepspace.jeepforum.com/tednelson83
"told it is an 8.27 inch ring gear, slightly better than 8.25"

http://www.offroadadventures.com/articles/view/id/256
"the modern version of the Mopar 8.3"

http://www.jeepcommander.com/forums/showthread.php?t=4830&highlight=corporate+axle&page=2
Look at post #13 here.

According to a googled "mm to inches" website, 213 mm (whats on the page provided by the OP) is almost 8.4 inches. so thats strange.

 

[Root Moose]

"Corporate" is not a company per se, it is a reference to the manufacturer in question building their own axle.

GM Corp axles are GM axles. ChryCo Corp axles are ChryCo Axles. You could argue that a Ford 9" is a Corporate axle (as in Ford Corp) but no one calls them that.

The ChryCo 8.25" doesn't have a ring gear that measures 8.25". It may have been once upon a time but it doesn't in production the last 20+ years AFAIK. Kinda like the current Dana 44 in a JK isn't really a Dana 44 per se.

ntsqd is on the correct track I believe. 8.3 is probably someone's sloppy cut-n-paste from a spreadsheet with the field width set incorrectly.

 

[SixLug]

The ChryCo 8.25" doesn't have a ring gear that measures 8.25". It may have been once upon a time but it doesn't in production the last 20+ years AFAIK. Kinda like the current Dana 44 in a JK isn't really a Dana 44 per se.

Just out of curiosity, and not trying to hijack, but why isnt the JK 44 really a 44?

Otherwise, you guys are probably right...why would they change the axles around so much for only fractions of an inch difference....8.3 is prob 8.25.

 

[Root Moose]

I forget the details but IIRC it has different bearings, the ring and pinion may be different in some way as well... either configuration or involute shape or something. I think I read somewhere they wanted to call it a Dana 48 or something but marketing said "noooooo!".

If you price some parts I think you'll see that there is a break point for the Dana 44 in 2006/2007. Different prices and part numbers on either side of that date for Wranglers. The change is a bit more than just the "thick" gears that TJs used (which is different from traditional Dana 44s yet again).

 

[ntsqd]

Late Jeeps use a D44 variation that has a shorter pinion gear shaft than the 'traditional' D44.

I'm not saying that the axle in question is the "Mopar 8.25", just that the evidence wasn't conclusive. Were it me I'd call one of the reputable axle shops (Tri-County Gear comes to mind) or one of the Differential mfg's and ask them about the axle.