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-   -   Rear Diff for Unknown Axle (http://www.wranglerforum.com/f218/rear-diff-for-unknown-axle-132164.html)

andiesel 01-09-2012 03:16 PM

Rear Diff for Unknown Axle
 
I have a 93 YJ which the PO did some frankenstein work on...I find something new that wasn't done quite right every time it goes into the shop.

I took it to get the brakes cleaned up and serviced, the guy was old school and loves jeeps. I have a couple of things going wrong right now, but I'm most concerned with:

Rear differential isn't meshing properly (?) but the mechanic wasn't sure. I get a bang/kick noise randomly - he thinks there's something not working quite right as one tire is locking, and the other isn't. I've had someone describe it as one tire looks "loose" when I'm stopping.

Here's the twist: the mechanic tells me this isn't an OEM axle. His best guess is that it was off of a truck.

At this point with some supervision I need to crawl under there...I want to pop off the cover and replace the fluid. I have a Chilton, which I hope will tell me what kind of fluid I need.

Advice, tips, guesses on my axle? How often does the diff fluid need to be changed out? I can post pics later.

****sorry...axle...no sleep.

flatline 01-09-2012 03:35 PM

sounds like a detroit locker in the rear. need pictures. chiltons don't tell much, probably say use gl-5. gear oil. I change diff fluid after a lot of water crossings, but the book probably says every 50,000.(that's a guess) I use mobile one 75-90 synthetic.

kmanator 01-09-2012 03:50 PM

Need a pic. of the rear cover to identify.Could be a ford 8.8 in there and some of those came with a limited slip.

andiesel 01-09-2012 04:32 PM

I will post pics tonight. best case the fluids were changed 2 years ago. but I've put less than 10k miles on it. not a daily driver. going to the dunes for my bday in a few weeks and want to clean up the problems.

andiesel 01-09-2012 09:48 PM

ok here are some pics - sorry I just got home and it's dark out. let me know if anyone can help based on these.

http://i1222.photobucket.com/albums/...esel88/004.jpg

http://i1222.photobucket.com/albums/...esel88/003.jpg

http://i1222.photobucket.com/albums/...esel88/001.jpg

IndyJeepMan 01-09-2012 10:33 PM

Quote:

Originally Posted by andiesel
ok here are some pics - sorry I just got home and it's dark out. let me know if anyone can help based on these.

I believe that is a OEM Dana 35.

Its definently nothing out of a truck, or an 8.8

95JeepDude 01-09-2012 11:54 PM

Yup d35! It still has the track bar mount and everything.

loganInaYj 01-10-2012 12:01 AM

Yeah d35 it is. Same hunk of crap I have

tnjeeprider 01-10-2012 08:57 AM

It is a D35 and if you have a 4 cyl. it will 4:11 gears. It sounds like your spider gears are going out. They are usally the first thing to go.

andiesel 01-10-2012 10:40 AM

Quote:

Originally Posted by tnjeeprider (Post 1906743)
It is a D35 and if you have a 4 cyl. it will 4:11 gears. It sounds like your spider gears are going out. They are usally the first thing to go.

I have a 6cyl engine. Sounds like the consensus is I have an OEM D35 axle/differential. (thank you thank you :flowers:)

Sorry I'm a little uneducated on this. My goal this weekend is to take it apart, drain the fluid, take a ton of pics, and try to figure out what is going wrong.

what kind of diff fluid and how much will I need?

andiesel 01-10-2012 12:12 PM

Here's what I think I need (based on some research):

- socket set (1/2")
- oil pan
- diff fluid (what kind/how much?)
- rubber mallet
- brake cleaner
- sealant (what kind?)
- most important: paper towels

Do I need a suction pump to put fluid back in, or is it relatively easy to pour it back in when you're refilling?

JeepAddOns-Chris 01-10-2012 04:47 PM

Heh, if your mechanic says that's not a stock axle, you might want to look into a new one. :)

3.75 pints of gear oil is what you need. RTV sealant. I use a fluid transfer pump otherwise it will get messy and gear oil stinks.

andiesel 01-10-2012 04:55 PM

Quote:

Originally Posted by JeepAddOns-Chris (Post 1907908)
Heh, if your mechanic says that's not a stock axle, you might want to look into a new one. :)

Thank you for the recommendation :flowers:

The day I find a mechanic that is right 100% of the time, and isn't ripping me off...well...pigs and wings and all that. But yeah, that's a pretty big screw up.

That was one of my trips minus a guy friend. I need to get a loaner tough guy to go with me to the mechanic. :banghead:

JeepAddOns-Chris 01-10-2012 04:59 PM

Hey, we all start somewhere. I can say this about mechanics and what you can learn yourself from forums. 99% of the time, the forums and the general commonwealth of knowledge here will know more than the best mechanics out there. A general mechanic has to know enough to work on all cars, but forums are specific to one particular vehicle and a group of thousands of enthusiasts will usually be able to tell you stuff even the mechanics can't figure out. ;)

andiesel 01-22-2012 02:40 PM

performed service - pics...any obvious problems?
 
ok so I performed a rear diff service, pulled the cover off, cleaned out the insides, scraped off all of the old sealant, sealed it back up and put in new fluid.

once I took the cover off and cleaned out the gears I took some pictures (sorry for the quality, I only had my phone on hand)...is there anything in here that looks obviously worn or looks like a problem?

when I drained it, it was low on fluid and the fluid was pretty gross. it feels like it's running a bit smoother, but I'm still getting a "bang" or a kick when I'm cruising to a stop.

http://i1222.photobucket.com/albums/...1-20214501.jpg

http://i1222.photobucket.com/albums/...1-20214449.jpg

http://i1222.photobucket.com/albums/...1-20214440.jpg

Nubby55 01-22-2012 06:11 PM

That looks like a Limited Slip Dif., and that's a good thing, most LSD need a friction modifier added at oil change, some one that knows what to add will chime in, and you should run matching rear tires with same air pressure.

Nubby55 01-22-2012 06:26 PM

Oh, it is set up spring over axle, [SOA] :thumb:

andiesel 01-23-2012 11:43 AM

I have leaf springs, I can't find any information readily available online as to whether I have a limited slip differential or not...

ninfivfo 01-23-2012 12:15 PM

That looks a little like a Detroit LSD, any where on the case have a circle shape?

andiesel 01-23-2012 12:18 PM

Quote:

Originally Posted by ninfivfo (Post 1952028)
That looks a little like a Detroit LSD, any where on the case have a circle shape?

I remember a symbol on the case, but would have to take a look at it later tonight. Anything in particular I should be looking for?

Cons_Table 01-23-2012 12:28 PM

Could be a detroit locker or a detroit trutrac because I believe they both look relatively similar. Whatever it is, its aftermarket. Someone may be able to chime in with a difference in the two (as far as appearance). If its the locker, banging is normal with the detroit as it "unloads." However, I am not sure that the trutrac should make noise.

ninfivfo 01-23-2012 12:33 PM

I have a trutrac and it looks different then that, case is similar but there is 2 deep notches in the sides. Here is a LSD Detroit American Four Wheeler Jeep Parts & Accessories
In that link you can see the circle thing I am talking about, should be same on opposite side.

ninfivfo 01-23-2012 12:35 PM

This is a turtrac that I have in the d30 of my yj, notice the big notch on the side. The locker does not have that I believe, it is a full solid round case from what I have seen. Yes I know the pinon is rubbing going to rebuild it soon.
http://i43.photobucket.com/albums/e3...J/IMG_1444.jpg

andiesel 01-23-2012 12:43 PM

Quote:

Originally Posted by ninfivfo (Post 1952091)
I have a trutrac and it looks different then that, case is similar but there is 2 deep notches in the sides. Here is a LSD Detroit American Four Wheeler Jeep Parts & Accessories
In that link you can see the circle thing I am talking about, should be same on opposite side.

there is a circle...I looked back through my pictures, and found one that shows the same marking. so it looks like it is a detroit locker. :punk:

Quote:

Originally Posted by Cons_Table (Post 1952078)
Could be a detroit locker or a detroit trutrac because I believe they both look relatively similar. Whatever it is, its aftermarket. Someone may be able to chime in with a difference in the two (as far as appearance). If its the locker, banging is normal with the detroit as it "unloads." However, I am not sure that the trutrac should make noise.

good to hear that the banging is normal...so I shouldn't have anything to worry about? :flowers:

sounds like I need an additive? any help on that?

ninfivfo 01-23-2012 12:51 PM

Think it is called a friction modifier is what you want and from what I understand some diff oil comes with it. Just to clarify something if that is a locked you wont need an additive now if it is a clutch type lsd you will. I do not know what that has so cant help there but I am sure others can.

4Jeepn 01-23-2012 01:00 PM

I would also check, seeing has you have a spring over, if you have a rear traction bar. This will be a bar mounted at or near the rear of t-case skid plate area and will attached at the rear axle. This could also be part of the issue you are having if its missing/not install correctly.

Cons_Table 01-23-2012 01:06 PM

I dont believe there is any sort of additive needed for a detroit. I do not have a detroit, but I have driven a rig with one. My buddy said that in his jeep he only felt it unload a couple of times ever. Has your noise recently started up, or has it always done it? I have also heard that some detroits act up more than others.

anamorph 01-23-2012 01:33 PM

Help from the Beas
 
Unless the axle has been swapped out, it is a DANA 35. Soundes to me like there is a tooth missing on either the pinion gear or the ring gear. You might want to check and make sure that the spider gears are staying in place also. The PO may have tried to regear and not know what he was doing. Good luck. Regearing and differential probs are a bitch!:punk:

lynskynbnd 01-23-2012 01:47 PM

Detroit Locker in my D35
https://fbcdn-sphotos-a.akamaihd.net..._8242587_n.jpg

Close up on the bench
https://fbcdn-sphotos-a.akamaihd.net..._1636834_n.jpg

-----> More pics here <-----

andiesel 01-23-2012 02:24 PM

ok to sum up so far:

- Leaf Spring suspension
- Dana 35 Axle (OEM)
- Detroit Limited Slip Differential (based on all of the pics on here vs. the pics I've taken it looks identical. thank you everyone for posting pics and links...very helpful)
- I am MISSING my rear sway/track bar (also, the lift was done with spacers by the previous owner and the leaf springs are shot...that's my big 2012 project to replace the suspension)

I changed the fluid following this set of instructions: Axle Differential Service

I used Castrol 80w-90 which says it works fine for limited slip...so I'm going to assume I don't need any additives at this point. While I was cleaning out the insides I did not see any gouges, obvious wearing, or marks that would indicate something was going horribly wrong.

The banging noise has been going on since I purchased my Jeep 2 years ago. It happens as I'm cruising to a stop or slowing down. I would say on average driving around town this will happen 1-2 times while running errands on city streets (all stop and go).

After I changed the fluid I still got a bang, but while testing out turns it felt a lot smoother.

How worried do I need to be about the banging?


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