differential rattle

[dlb]

i've discovered a cause of part of my front end rattle. the inboard end of the CV that sits in the differential has play. i can wiggle it and push/pull it about 1/8" in and out of the diff--not a LOT of play but considering there should be no play at all, it's a lot. the driver's side is firm.

i replaced the CV last spring or summer in the hopes of fixing the rattle but it had no effect. i've just been messing around and have been planning on doing a front end overhaul to get rid of the rattle and also as preventative maintenance but i'm not sure what to do at this point. is this something that can be adjusted on or in the diff, or is that making a huge headache? my trans is in good shape and shifts in all gears very smoothly so i don't want to get rid of that if possible. worst case scenario, can i remove my entire trans and just replace the diff from any '85-'88? i know of another '87 nearby that has the trans.

[splatterdog]

It's sounds like it may be beyond adjusting it. Ever find any metal on your drain plug magnet? It could be from worn carrier bearings, but you would likely have lots of gear noise if this was the cause and play on the other inner joint. Worst case- where the side gears ride in the carrier can be worn out. That would be the more likely cause with only one sloppy cv joint. Time for a new carrier(piece the ring gear bolts to)and full rebuild or slap in a used whole front diff case it sounds.

Check the FSM about checking and adjusting procedures if you want to dig in to it. You will need a dial indicator and torque wrenches and a hydraulic press. Just be careful. Get it wrong and things could go horribly wrong while the trans suffers collateral damage.

[Petros]

You should be able to swap out the front diff, I think the front diff housing is integral with the bell housing. But I would not replace the front diff yet.

The spline moving in and out a bit is not unusual, and should not affect anything. IF the seal stays on the seal race it will not leak and cause no issues. There is a snap ring that holds it in and sometimes they are not as stiff and will allow it to move in and out on the spline. If it wiggles in rotation (as if the spline shaft was worn out) or if you can jiggle it fore and aft, that would be bad and if it is not the spline on the half shaft, the diff bearing or the diff splines are worn and sloppy. These typically will whine or roar, not rattle. I would make sure you isolate the cause of the rattle before I pulled the trans, that is a big messy job.

[splatterdog]

Good point Petros. I would narrow it down a little more. If it doesn't appear to be anything else, maybe the diff cover can be removed without too much fuss to get a good look inside and see if there are urgent repairs needed.

The seal isn't leaking so that is a good sign.

[dlb]

thanks for the input, guys.

yes, the spline does slide in and out of the diff about 1/8" but it can also be wiggled from front to back (of the car) and up and down. there is no play in the rotation and no leak. if i'm driving on a relatively smooth surface there are no unusual sounds, but when i go over bumps the rattle is very audible. the way you describe it petros, i imagine it would be the diff bearing.

it's been like this for over a year now and i've replaced other parts trying to eliminate the rattle. i have replaced the sway bar end bushings, ball joints, and passenger CV. all were worn, had play, or were non-existent (!) and due for replacing anyway. i was planning on doing the tie rods (inner and outer), control arm bushings and replacing the strut springs all in one go soon but this is definitely a separate issue from any of those.

does any of this info help to narrow it down? i'm going to look at the FSM right now.

[takza]

I think the clip isn't really in the groove....there should be almost no endplay if it is set right...the other slop radially isn't important and isn't likely in the diff bearings anyway. You DON'T want driveline "slop" in the axle...as in when turning the axle with the diff in one place....though the spider gears within the diff will show some slop.

[dlb]

takza, are you referring to the c-clip on the inboard end of the CV shaft? and just to clarify, when you say radial slop, which direction of slop are you referring to?

[takza]

3 kinds of slop:

end play that the clip should stop....but you have 1/8th "?

radial play which means front to back and up and down and so forth...most CV axles I've seen have a good bit of this

driveline slop which means that there is looseness in the splines where the axle mates with the diff...meaning when you turn the axle vs the diff

Seems that the clips they supply with these axles are not well made...they have to be an exact diameter...heat-treated to hold a good tension...and shaped exactly right.

So my guess is that the clip isn't seated right...but I'm doubting that that's what is making the noise...hard to say. There are 2 tie-rod joints on each side...I had to replace the inner ones on mine...made a clicking noise over bumps like on a gravel driveway or a lawn.

[dlb]

well i'm just waiting for the inner tie rods to show up and then i'll be doing those, the control arm bushings, and driver's side ball joint so i guess i can just do that and then see. the rattling has been like this for a year so it can wait another few weeks. i was just messing around and thought that it might be it but you're right, i should do the other stuff first since it needs it anyway and thaen re-evaluate. TBC: to be continued...

[dlb]

an update: i finished my front end work on ron tonight. i replaced the passenger side CV, both ball joints, inner and outer tie rods on both sides, both strut mounts, passenger side control arm bushing, and replaced stock springs with camry springs. i also did the sway bar end bushings a while ago. the front end is now very solid and free of any weird sounds and i'm totally pumped. those sounds had been bothering me for long time. now on to the next stuff on the list.

[SynthDesign]

Sounds like some of the same noises I'm dealing with. Hope you solved the problems!

DON'T ATTEMPT TO ADJUST THE DIFF. YOURSELF! Seriously, a Good Diff shop is much cheap than something breaking. The gear-wrap is a hard thing to do yourself right. Leave it to the professionals. I pulled a ft dif because of this noise and rock and mine was stated to be fine except for a bit of wear. Basically it wasn't the problem and I'm startin to think my trans has developed wear somewhere internally , but it still has that same 8 to 10 degrees of rotational rock and drives fine.

Play from between the c clip and the spline horizontally is normal. Especially with reman'd axles as the hubs are a few mm longer sometimes.

Also the front Diff can be removed from the car w/o removing the trans.
-Drain trans fluid, Remove the front axles, Remove Ft Diff cover. Evenly and slowly remove 4 bolts hold diff mains in place. Pulls out with even level pressure.