CJ7 Axle Strength(stock20and 30)

franked · #1 (**permalink**) 05-31-2008, 03:53 PM

Hello, new to the forum here. Wondering how my 78CJ7(4spd,6cyl) will do on a Rubicon trail run with the Stock 20 rear and 30 front axles, should I even bother putting lockers/true track/limited slip in these axles? I have 33 inch tires and want to do some trail runs. I hear 44s are the way to go, but I'm really trying to keep this thing on a low budget. , could I ensure the life of these axles by going to a 31 inch tire instead? Should I just see what happens, or beef it up? Thanks, Frank

Collin the Hen · #2 (**permalink**) 05-31-2008, 06:28 PM

If you don't already, I'd put a one piece axle kit in from Superior or another axle supplier. They say it makes it as strong as a 44. Either way, it definitely make it stronger. If you're planning on a future 44, just put a Lincoln locker in for the Rubicon!

franked · #3 (**permalink**) 06-01-2008, 09:30 AM

One piece axle, does that mean no diff whatsoever? I still plan on driving this on the road. I think dana 44's are eventually the way to go.Does anyone think I'll get away with it once on the rubicon, or need a tow home? lol ,If I don't upgrade I'll probably be taking the bypasses. Anyone know the length difference with a modern Jeep Rubicon axle and my CJ7? I may have a hookup to snag some of those axles,I would need new wheels I guess, if I did that. HMMMM this whole thing gets more expensive....

redrooster · #4 (**permalink**) 06-01-2008, 07:32 PM

Your'e right, it gets expensive quickly. My advice would be to go to some trail rides and see what you like. Take it easy on your stock axles, they will break with 33's if you bounce, rev and dump the clutch.
When folks say 1pc rear axles, they are referring to the axle shafts, not the housing and differential. CJ's came with axles that had a shaft with a splined end at the differential and another spline at the hub. The hub end is prone to strip out. The one piece kit eliminates the splined hub. It will come with new axleshafts, seals and bearings. It's almost a mandatory swap.
BTW, your 78 is considered to have Narrow track axles. The CJ got wider track axles in 82. Yours are something like 4" narrower overall than the wide tracks. No difference in strength.
If you wanted to go one better on strength and have the one pc axle, try to find a narrowed Ford 9". It should have the same lug pattern. They came on everything from the small broncos to cars. I would take a 9" over a Dana 44 any day.

Collin the Hen · #5 (**permalink**) 06-01-2008, 08:33 PM

Thanks for clearing things up about the one piece thing, redrooster. Another cheaper mod for the 20 is welding the axle tubes into the diff case. This prevents the axle tubes from bending. I've actually read about some guys putting 35's on with the one piece and the welded tubes. I think the dana 30 can hold 33's OK, if I remember correctly.

franked · #6 (**permalink**) 06-02-2008, 01:55 AM

Well thanks for the advice everyone, I have talked to some guys about this situation, and have heard the same thing, (what the one piece means) I had a guy recommend doing that and a spool,.He said he never broke with 37s on his. I found a guy locally with a 44 rear, and 30 front with lockers for 500 together, but there was someone else coming that had called first. Needless to say, they were sold, SIGH! I also have a line on parts in a wrecked rubicon, the guy that told me about it says that they are 44s with lockers from the factory. Another gut told me that putting the front from one of those in a CJ is a nightmare because the pumpkin is on the other side in the front, besides the fact that my I would need different wheels because of the different bolt pattern and axle width...... maybe I can find a cheap 9 inch out of a ford van at the pick-n-pull and get it narrowed cheap, hmmmm. Thanks again. Frank

Macdp · #7 (**permalink**) 06-02-2008, 07:14 PM

I'm originally from So Cal and ran the Rubicon many times with my 85 CJ-7, semi stock Dana 30 and AMC 20, 33" tires, stock straight 6. Two things 4:11 gears and a Detroit Locker with flanged axles in the rear and you won't need to use the go arounds. One (after many trips) failure lost the right rear axle bearing on the way home, trailered it home the next day- out came the flanged axles and a full floater went in-nice for towing-but there were issues there too. My "new" 1984 CJ now has Air lockers and 4:56 gears, and I went back to the flanged axles.
Lockers and Gears make the difference of how hard you have to work it.

franked · #8 (**permalink**) 06-08-2008, 03:46 AM

Thanks for all the advice everyone, as it turns out, I found a Dana44 from a 74 CJ5 with a posi for 160.00(3.73-1). I can get a Detroit locker for it for 200 from a friend of mine. Is there anything else I need to do for that to make it last? I found some shorter shocks, and mounts to attach the shocks to the axle so they don't hit stuff at the u-bolt plates.

I found a posi unit of some type on the floor of my jeep(a carrier with clutches) on both sides, how do I tell what it is? I would like to see if it might be for my dana 30. thanks, Frank