Front Differential

[Joel]

So I have had this noise when cornering hard under power ever since I got my tercel a year and a half ago. I attributed this noise to a bad cv joint. Last Wednesday as I was leaving work It suddenly sounded like I had a gnome taping a hammer under the front of my car. A quick diagnoses led me to believe that it was defiantly a drive train problem not in the engine. I put it up on the rack at my dad's shop and it felt like the left axle had a little extra slop in it so I ordered a new one thinking it had finally gone bad. On the way to the shop to change the axle this evening I experienced a sever failure in the drive train. I was able to get it back home and put it on a trailer using 4wd. After the easiest axle swap in my life I eagerly jumped in ready for all my woes to be over. Sadly the horrible clunking and binding was still there. We put it back on the rack and the noise seams to be coming from the front differential. Any suggestions on my best course of action to get my beloved car back on the road. Do I have to replace the whole diff or can I just replace the guts. Does any body know whether I may be looking at just a bearing or am I looking at a whole gear cluster. (I am assuming that originally it may have been a bearing which totally failed today and may or may not have caused gear damage) Basically where do I start and how bad is do you think it is gonna be. Any tips, advice or other related knowledge will be greatly appreciated.
Thanks in advance
Joel

[takza]

Check recent thread by Mac?

[Joel]

thanks takza. I am also wondering what all is involved in the swap if anyone has done this before.
joel

[takza]

Sounds like a side gear (planetary) that has lost some teeth. Guess you start by taking the cover off to see what's what?

[Mac]

when my differential failed i felt a good shock travel through the gearshift, and a slightly audible noise, but it otherwise drove fine until i reversed out of the driveway and a half of a pinion gear made a hole in my front differential.

without a doubt you'll have to take off the front diff cover to see whats happened, but I expect the only salvageable part of the front diff at this point will be the differential carrier, based on how long this has been going on, and the degree to which its making noise.
considering how much the cost of all the (dealer only) parts to rebuild the differential, its without a doubt going to be cheaper to source a whole new-used transmission.

the bearings are probably fine, roller bearings never fail due to regular wear and tear, they only fail due to a lack of oil/lubrication or some sort of extreme situation.

[Joel]

I have one more question. I have been looking for but can't find information about changes to the drive train over the years. I don't want to get a transmission and have it not fit. I searched the forums and couldn't come up with a narrow enough search to make it reasonable to look through (< 20 pages). The car is an 83 4wd Manual tranny. If anyone knows or can point me in the right direction to find this info It would be greatly appreciated.

This is what I think I know so far:
the manual 4WDs all have the same final drive so the diffs are the same.
at some point the gearing in the transmission changes. I know I found this on the forum somewhere before but I can't seem to find it now. I think that point was 84 or 85 but am not sure.

What I don't know:
Are the different transmissions physically compatible. If get one from an 85 can it go in an 83? are the input and output shafts the same or will I have to use a newer transmission for differential parts (assuming that really is all that is wrong)
thanks a bunch to anyone who can help out.
Joel
:edit
so I am searching through the forums and I was struck by a 'brilliant' idea. What if I remove the front differential and just drive it as a rear wheal drive. I would even have an anti theft leaver. Just put it in front wheal drive and nothing will happen when someone tries to drive off with it. Hey I could leave the keys it in the worst part of town and when someone tried to seal it they would sit there confused thinking the clutch was out or something.
Ok seriously as a temporary fix to get it on the road again. ie. so I don't have to borrow my dad's gas guzzler. This should work shouldn't it. I would also be able to do an inspection while it was apart to see what I actually need.

[Neu]

so I am searching through the forums and I was struck by a 'brilliant' idea. What if I remove the front differential and just drive it as a rear wheal drive. I would even have an anti theft leaver. Just put it in front wheal drive and nothing will happen when someone tries to drive off with it. Hey I could leave the keys it in the worst part of town and when someone tried to seal it they would sit there confused thinking the clutch was out or something.
Ok seriously as a temporary fix to get it on the road again. ie. so I don't have to borrow my dad's gas guzzler. This should work shouldn't it. I would also be able to do an inspection while it was apart to see what I actually need.

You would burn up your rear differential so quickly it wouldn't be worth it. These cars aren't meant to be in 4wd on cement or really even bad gravel. When i'mwheeling i keep mine in 4wd only when i'm actually in sand/mud/water. Otherwise it's in fwd. I pop it back into fwd as soon as i'm out of whatever i was in.

[xirdneh]

i believe the transmissions are the same
the differentials are different

i had an 83 tercel with the 83 rear end and an 87 tranny that was installed by a former owner by accident.
we drove it like that for a year or so
it was not a problem on snow and ice or loose gravel
it was noticed right away when you hit a dry patch of pavement or hard dirt
so we were careful to pop it out of 4x4 at the right time
eventually i replaced the rear differential to match

i have several broken trannys with good differentials
i took two of them apart
did not have tools to remove diff. from alum housing
so there they sit
they are available for cost of shipping if anyone wants one

[Mac]

if you can make it RWD go for it, in my situation it wasn't possible, theres no reason it will cause excessive strain on anything, your just moving the power from the front wheels to the rear, its a binding 4wd system on pavement that strains the car.

[Joel]

Thanks for all your comments. I finally had time to take the cover off the differential. The ring gear is scarred all the way around. The pinion gear has about three teeth sheared off of it. also both drive shaft bearings are heavily worn. Oddly I found a small piece of sand stone inside the differential. along with lots of metal shavings and chips. can't figure out how the sandstone got in there. I guess someone changed an axle in on pea gravel. As best as I can figure the worn bearings allowed enough extra slop in the cluster that the ring gear bound with the pinion gear and sheared three teeth off. Once the teeth were gone it broke teeth off the ring gear.
So now I know that I am looking for a 'new' transmission. Or the ring gear and pinion gear from an 83 or 84. or some other similar combination. Or I may just clean it all out and try rear wheal drive. There may be something I can work with at the 'local' pull-a-part so I shall have to check before I go to much further. Knoxville and will be traveling to Atlanta if anyone knows of one available 'near by' let me know.
Does anyone know where I could find a copy of the service manual that used to be on the website I wouldn't mind having a copy. I wasn't smart enough to download a copy while it was up.
Thanks again
Joel