Jeep Enthusiast Forums banner

problem on dana 30 cj7 front axle

1K views 11 replies 6 participants last post by  1978jeepcj7 
#1 ·
I took the front drive shaft off of my 78 cj7 and when I went to push the jeep (no engine in the jeep) the front differential made a popping and grinding sound and now the jeep will not budge. The yoke on the differential is extremely tight, almost locked up. If I lift both of the front wheels off the ground and spin one tire forwards, the other tire will spin backwards and they turn with very little effort. While doing this the yoke doesn't move at all. I am needing to move my jeep closer to the garage and when I set it back on the ground it won't move, its like the front brakes are on. Should you be able to push or drive the jeep without a front driveshaft attached without hurting anything. Thanks for any help!
 
#2 ·
You have a differential problem. Pinion bearings siezed, carrier bearings siezed, R+P broken and jammed. Since you stated that the pinion yoke won't turn, I would suspect the bearings are at fault. I'm interested that you haven't had any problems with this prior to removing the driveline, as that shouldn't make a difference.
 
#4 ·
Sounds like a broken pinion. Your differential is differentiating (tires going in opposite direction. If this action is smooth with no spinning yoke then it's got to be the pinion snapped. Time to pull stuff apart and make some magic happen.
 
#5 ·
Thanks for the responses! When I bought the jeep I drove it home to where it sits now. Everything worked to at least get me to the house, however there was an aweful noise coming from underneath the jeep, sounded like bearings were completely shot and I couldn't pin point from where. When I pulled the front drive shaft off the yoke on the differential was about as sloppy as one could get without falling out on the ground. I guess when I went to push the jeep there was nothing there to support or center the yoke and I guess something inside finally bound up. Unfortunately for me the people who owned the jeep NEVER checked the oil in the front differential and when I pulled the cover off about a cup of water came out and what was left looked like thick brown clay, not good. I guess this is just about as good a time as any to learn about rebuilding a differential. Any suggestions? Thanks for all the support!
 
#6 ·
A service manual would be helpful. I find that the ring and pinion setup is more differential housing specific than ring and pinion gear/carrier specific. I have had good luck using the same shims (carrier and pinion) that were in the housing originally to set up new components. Everyone, feel free to chime in if this has not been the case with you. I will be a good place to start anyway.
 
#7 ·
As the veteran of many R+P replacemants, my advise is simple. You either 1) have someone experienced to help you. Or 2) pay a mechanic to do it for you. This is one of these times where a mistake in set up will cost you a new set of gears. If you choose 2, strip and remove the housing and take it into the shop. This will reduce your labor costs to about three hours.
 
#8 ·
1978jeepcj7 said:
Thanks for the responses! When I bought the jeep I drove it home to where it sits now. Everything worked to at least get me to the house, however there was an aweful noise coming from underneath the jeep, sounded like bearings were completely shot and I couldn't pin point from where.
I think you answered your question.Didn't the seller tell you about this problem?
 
#9 ·
pay a mechanic to do it for you. :confused:
But what do you learn by doing this? I went online and read everything I could about doing the work myself. Then after I felt comfortable I dug in. Just pay very close attention to what your doing. It helps if you have a coach ( Someone to help if you find a sticky spot) The first axle will take 1/2 a day or better then the next one goes much faster.
 
#10 ·
It's a matter of what your comfortable with and what your aptitude is. I like to know how to. I do pretty well at it. Some people don't like to get into unknow territory. It's really up to you. Realize that some specialized tools are involved that you will either need to borrow or buy for this particular project.
 
#11 ·
Rockram1 said:
But what do you learn by doing this? I went online and read everything I could about doing the work myself. Then after I felt comfortable I dug in. Just pay very close attention to what your doing. It helps if you have a coach ( Someone to help if you find a sticky spot) The first axle will take 1/2 a day or better then the next one goes much faster.
I belive that most any repair can be done by studying and appling that knowledge. R+P's are the exception. While it can be done, the need for equipment like presses, bearing splitters, in/lb torque wrenches, and dial indicators cost prohibitive to start. While I've been lucky and had some sets "fall" together, others have been a serious battle to obtain a good picture. I can think of two sets of new gears that I had to return to the manafacture due to neither myself or the other mechanic being able to get a good contact pattern. If you don't know what your looking for you can burn up a set in a hurry. This becomes more cost prohibitive than the tools. if someone wants to attempt this, power to them. They might get lucky, they might be good. Or they might think they have it, only to break some teeth and have the opportunity to do it again. If someone wants to learn how to set R+P's, my suggestion is to go to the local U pick yard and purchase an old Ford 9" and do a rebuild on it. They are very simple to do, and you can always sell it on Ebay later.
Just my .02
Scott
 
#12 ·
Thanks for everyones help and suggestions. I am very comfortable with doing mechanical work as I have rebuilt a couple of automatic transmissions and valve bodies. I have also been involved in many other mechanical projects and like a lot of people have mentioned is do your homework, research and pay attention to DETAIL. The tools shouldn't be a problem, so all I am missing is experience on differentials and this is the reason why I bought this jeep is to learn and have something fun when its all done. Trust me if I dig into this thing and its something that I am not comfortable with I will seek help. The guy I bought the jeep from owned it for twenty years and knew ZERO about maintenance and he told me so. I paid $2,200 for it and he said it had only 56,000 original miles, 304, A/C and automatic transmission, solid frame "which I inspected", little rust "which I inspected" and the best part everything is still on it that came on it the day it was bought " no one screwed with anything, all the parts are there". Thanks again! This forum is awesome, I appreciate all the experience that is shared.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top