Upgrade the axels?
 

I have a '94 ZJ 5.2 with 4.5" lift and 31" tires. It has the Dana 30/35 with 3.73 gears. My question is can I install Dana 44 axels front and rear? Is it worth the expense to gain added reliability. Currently not having any issues with axels I have, just have heard a lot of bad comments about 30 & 35.

How big of a tire do you want to run?That dana 30 can handle 35s if built right and you swap in a xj high pinion which bolts in but the gear ratio will be a problem since most xjs are 3.55.The dana 35 is the weak link you have but you can swap in a dana 44a from another zj and that if you truss it and run a skid plate under it run 37s on it.If you want bigger then a 35 inch tire well 1 ton axles are the only option,The ford dana 60 and either a gm 14 bolt full float or a ford sterling from the 90s.But swapping in a none bolt in axle is pricey and takes time so keep all that in mind.

Never plan to run bigger than 33's. I don't do any hard core stuff. Just reading all the bad stuff about the 30/35 made me wonder if I should plan a swap.
What year ZJ had the Dana 44 rear?

v8 zj 95 is to 98 and its a dana 44a the A stands for aluminum.Which it don't use any normal 44 diff and gears so if you want to get a locker or re gear it the options are limited but out there.More info on it http://d44tech.com/Dana_44A.html

Thanks for the help man.

No problem

I looked at all the different options (44, 8.25, 44a) awhile back and decided to put the super 35 kit in the axle. I mainly take the family out and did not want to chance breaking an axle which is why I did the upgrade. There was a guy in my club that had a D35 in his jeep and he was not easy on it and it did fine for several years. Then he installed a gear reducer and twisted an axle. He was saying as long as you don't bounce your rig and put a lot of torque on it the D35 should be fine. he had a manual trans which was harder on it than our auto and ran 35's.

The hardest thing for ANY differential to survive is shock, as in total loss of traction, then recovering it at high rpm or loads. When I was drag racing, 90% of the stock classes were running 4-speeds. The guys who blew the rear ends were those that side-stepped the clutch on the line. I was taught to slip the clutch just enough to take out the slack in the driveline before you launch. I only blew a Posi unit once when there was a concrete starting pad and an asphalt track with a slight step between them. My SS Camaro had the GM HD 12-bolt rear in it.

In off-roading, you'd get that kind of shock when you get some air with your foot still on the power, then land or spin the tires, then suddenly catch traction. The D35 was designed for passenger cars and light trucks, not heavy pounding.

The weak point in a dana 35 is the housing its self and only way to fix it to truss it or retube the housing.

Solid advice guys, Guess I'll keep what I have. I'm not hard on any of my equipment. May upgrade it a little later. Again thanks.

If you really don't wheel hard and drive normal i doubt youll break either axle.I have seen mall crawler wranglers run 37s on those same axles and not break nothing.