Evening all...need to consult the greater minds on the matter of Dana 30 diff. feel silly asking, cause it is so basic but here goes..the subject is '08 Sahara 2D auto...fixing it up for my daughter (first time wrenching on a Jeep for me) and basically rebuilding all suspension- shocks, springs, bushings, bearings etc. (except front axle seals)...so I pulled the front axles, got new U-joints installed and new hubs/bearings....axles seem to settled in nicely on the way back in but here comes the rub....When I spin the input shaft , axles rotate nice and smooth/quiet - like butter, effectively no backlash of any kind. Good so far,,,but when I spin the axle however, I can feel the "notchy slip" if I hold the input shaft at the same time....(the diff. fluid was clean and nothing on the magnetic plug..literally nothing)...So, being a newbie to Dana 30 world..is this normal open diff. behavior? - spider gears slipping - is that what I'm noticing? I hope I'm being paranoid a bit here but I'd hate to button it all back up and find out I have knackered diff. and have to do it all again...lol...The Jeep came from an auction so I know nothing on history and did not check for this specific behavior before I took it all apart.
What say thee brighter/more experienced Jeep gear-heads?

Thanks very much for any insights.....Michael

 

Differentials are all very similar. They all have to have a little bit of play to mesh right, expand, and generally mesh together. I have never had an axle that didn't have a little bit of a clunk if I spun just the one wheel. If you are seeing something like 10+degrees of movement in the wheel before it chunks and engages, that's too much play and I would take it apart. If it's a degree or two, that's normal.

My $0.02. I'm an engineer and automotive enthusiasts that's been messing with cars for the past 15 years. Ive rebuilt axles and replaced at least one of everything. But I will note I am also fairly new to jeeps.

 

Spike 0180..Big thanks for your comment from a fellow Eng. and a hobby gear-head. I've worked on old Datsun and a V12 XJS, but new to the Jeep front as well. The spline engagement is actually pretty tight..... hardly anything with a slight "clink" -- nowhere close to 10 deg. you mentioned. what got me spooked a bit was I was slowly spinning one side and grabbed the input shaft and stopped it, and I could feel a "slip - tick tick tick" under my hand on the axle I was spinning...almost like "slipping on notches"...I'm thinking it is the natural part of the open diff. when it encounters the different speeds on both sides, but given I know nothing about this Jeep (and the diffs...lol)..I figured I'd ask some smarter folk on the list.
Appreciate your note - will continue plugging away and assume the diff. is ok.
Thanks! Michael

 

I assume you have the Jeep up on two jack stands so the wheels can spin independently. OR, are you putting the T-Case in neutral so you can spin the wheel? You can feel feedback from the T-Case gears if it's in neutral.

Are the wheels turned at all? Even a little bit of steering will generate a little feedback from the steering u-joints.

You might have a sticky spider gear bearing. If you have the Jeep up on two jack stands, one wheel is rotating forward and the other backward because the spider gears are stationary. But that doesn't explain why spinning the axle instead of the driveshaft gives the "notchy" feeling.

Just random thoughts.

 

AZ Jeeper....Thanks for the comments..good of you to respond. Yes - front axles are on the stands and T-case in N. When I spin the input shaft - smooth as butter. I'm almost done rebuilding the suspension (good day today) so at this stage it will be "let 'er rip" once I get the wheels back on. I may try to run it slowly on the stands (got 8 of them under the Jeep - 4 corners and 2 per axle) -- see if anything odd is happening. If good, will take it for a spin after with the same look/see.

Thanks very much! M

 

Sounds like the spiders working. My D44 locker is like that. Even with a V8 doesn't make noises so I don't worry about it.

 

Thanks Sixty4x4...Heading that way...got the axles buttoned back up. Need to finish with suspension and give it a bit of a test run. Thanks for the note...from down the street in YYC.

M