dbragg

iTrader: (7)

i searched. the search function is messed up, obviously. im VERY short on time. i either get this fixed or drive a civic to DGRR. so, help!!

i just finished the 5 lug swap on my SA. here are the specs on the rearend:

GSLSE housing and 3rd member
moser 5 lug axles
new bearings, collars, and spacers
this is the first time the rearend or driveshaft has ran since ive owned it


this car ran and drive perfectly with 4x110 suspension on it last week. so it has to be the newly added stuff.

heres the problem.

we got my car all together and went for the first ride today. it drives fine, but its making some noise. i let my neighbor, who is my helper drive my car whilei had to go get supplies with the girlfriend for DGRR.

heres all the info on the noise:

it seems to be louder under load. he took it down our road and on the way back you have to come up a steep hill. he said the noise was much worse when coming up the hill. which means its load sensative. we bring the car back to the shop and put it up on jack stands. we couldnt get it to make noise until we got to 3rd gear. as we go higher into the rpms is gets louder. i just finished pulling the whole rearend apart. i have the axles and 3rd member out. this is my first time looking at a 3rd member, but it looked it over closely and all the teeth look fine.

do i need to add some grease to the axle ends before installing them into the rearend?

also, im using royal purple 75 90 oil. i put the oil in last weekend. when i drained it out a few minutes ago it looked a whole lot dirtier than the royal purple in the bottle. i have a whole case of royal purple, so ill be using all new oil when i reinstall everything.

any help guys?

heres all im concerned about. is it safe to drive the car with the noise to deals gap? i hadnt planned on driving my car hard anyways. i dont want to do anything thatll risk endangering my girlfriend and i though. id rather go to DGRR yet another year without an rx7 than risk hurting someone.

so, should i take it?

Rx-7Doctor

iTrader: (13)

Bad differntial side bearings? Are the axles seating correctly in the housing? Possible bad u-joints on driveshaft unless that driveshaft was in the old setup.
I doubt that it is anything dangerous.
When you put in the complete rearend did you tighten all of the watts links after you put the load back on or while it was still up in the air?

dbragg

iTrader: (7)

i have no idea if its a bearing in the LSD or not. thats the only thing i can think of it being. i forgot to mention i did the old school trick of taking a screw driving and placing it on the rearend to listen to where the noise was coming from. i went from the center out to the end of teh axle tubes. the noise was definately louder right in the center. thats why im thinking LSD is f'ed up.

the old driveshaft is the small bearing. i have only driven on this driveshaft and rearend once for about a 1/4 mile. after that i swapped it all over to this new car that was running with stock suspension. i dont remember any noise coming from the rearend that day, but straight through exhaust from a SP 13b isnt very quiet

yes i didnt tighten down anything on the rearend till the car was sitting on the ground on all its own weight. it was a tight sqeeze.

i tightened the driveshaft while the rearend was in the air? i dont think i need to tighten it while the car is on the ground? but im willing to try anything. i really want this car to go to DGRR.

Rx-7Doctor

iTrader: (13)

If the driveshaft bolts came loose there will be a hell of a noise from that. Recheck the bolts.

dbragg

iTrader: (7)

i got under the car while it was on jackstands running. i got my friend to have it running and to get on it and let off repeatedly. the driveshaft didnt move at all other than spinning faster

i think its rearend oriented. my friends dad said he had a 280Z that the lsd started making a lot of noise. its rearend had a removable shield on the back of the rearend housing. he put the car on jackstands, took the rear cover off, and worked a thick grease into the clutch system in the lsd for a while. he said it made the LSD act perfectly. should i try adding some grease to certain locations on the LSD?

well, im hitting the sack for a nice 5-6 hour nap before i get started again tomorrow. i expect there to be a solution to my problem when i get on in the morning guysjk

trochoid

iTrader: (6)

LSD diffs need a special additive to the fluid for them to work correctly. I'm not sure if the RP fluid needs the additive for the clutch type lsds or not. Is the 75/90 fluid you used specifically for diffs, or is it a multi-weight tranny lube?

Rx-7Doctor

iTrader: (13)

All of the Royal purple products meet the LSD specs.

dbragg

iTrader: (7)

just checked, it contains the limited slip additive. its about time you show up?

seriously, i have to go to bed now or ill be dead tire for the drive tomorrow. so, trochoid, pull out that crystal ball and get to rubbing!!

dbragg

iTrader: (7)

whelp, im taking the civic...oh well

85rotarypower

Sounds like mabey the backlash or something is out of adjustment on your ring and pinion. Either that or bad side bearings or pinion bearings. I suggest changing out the bearings and having the diff setup by a shop. The LSD won't make any noise unless going around a corner if you have the wrong lube in there, so that can't be the problem. Its gotta be either the bearings or a wrong setup on the ring and pinion. But judging from the fact that the lube was dirty when drained from only that short drive, its a problem with your ring and pinion.

What you could do with the 3rd member out of the car, is put some paint on the ring gear and while its still wet spin the pinion to turn the ring gear 1 full turn. Check where the paint wipes off on the ring gear and that will tell you a lot about the way the ring and pinion is set up.

DriveFast7

iTrader: (1)

yep, check the contact pattern of ring and pinion.

trochoid

iTrader: (6)

If you loosened/removed the pinion nut, then you've upset the backlash and it will need to be reset along with a new crush sleeve. Sorry I didn't get back and answer soon enough, but you wouldn't have gotten the parts in time anyway.

steve84GS TII

Backlash is affected by the carrier position and pinion base shim.Adjusting these affects the pattern at the same time,which is why it can take several attempts to get the pattern correct without going outside the tolerances for backlash.Sometimes is impossible to acheive a perfect pattern on the drive and coast sides of the gears,backlash is more important,pattern can be in several places within an area of the tooth,and still be acceptable.

I dont know if youve worked on the 3rd member or not,it could just be worn out or bad from a previous owner.The LSD itself doesnt usually make any noise,except when cornering tight...when its actually doing something.Pinion bearings turn much faster than axle or carrier bearings,so they tend to make the most racket.They are also subject to more thrust loading and are smaller than the carrier bearings.
If you pulled the pinion center nut to change driveshaft flanges,and didnt install a new crush sleeve....then set the pinion bearing preload.....then its nearly 100% likely that you are hearing either........
1.Noisy pinion bearings that are too tight from over-squashing the crush sleeve.
2.Noisy pinion bearings that are too loose from not squashing the crush sleeve.
3.Ring and pinion are too close and are bottoming out because pinion was not drawn forward enough when tightening the nut (the results of number 2).

Bottom line......if you ever pull the pinion nut,you must replace the crush sleeve and reset the pinion bearing preload.And this is only possible to do after the carrier and ring are removed,which means you have just completely dissasembled the 3rd member.
Thats why is smart to never pull the pinion nut unless you are prepared to completely reset the diff.This is something that most people dont know how to do correctly.4WD rockcrawling taught me how to do diffs,and its quite a tedious job to learn, to the point that you are completely comfortable doing so.

speedturn

iTrader: (1)

You've got a lot of good advice above, all of which points to the pinion and it's setup or the clearance between the ring and pinion. You need to pull the 3rd member back out and check very carefully all the above items referring to the ring and pinion. The Limited Slip Differential units very rarely make noise themselves just from driving down the road; usually it's the ring and pinion.

dbragg

iTrader: (7)

i have never touched the driveshaft flange or the nut, but i dont know what the previous owner did. ill pm him and ask if he touched it. i saw a diagram somewhere a while back showing about testing the pinion ring setting with a grease and watching where its touches, same as process described above. ill test this, but it does me no good without a diagram to go bad to know what it good and bad. would this be in a haynes or FSM? what about removal of the paint after applying it to the teeth? or just not worry about it? if i cant get the probelm figured out ill just drive it as is, pick up another chunk, swap them and then redo this one completely with 4.44 and maybe a torsen or kaaz.

OLD RX-7

The way I see it is :- A process of elimination !.

There are to many unknown items :-

1/- "GSL housing" :-
Is it true and straight ?
Has it been shipped to you ? - ( unknown transit damage / abuse ).
Did the previous owners bent it ? ( easily done reversing hard into a curb will do it ).

2/- "3rd member" :-
Has it been shipped to you ?. - ( unknown transit damage / abuse ).
History / mileage, bearings, pinion & ring gearset wear ?.

3/- "Moser 5 lug axles"
Has it been shipped to you ?. - ( unknown transit damage / abuse ).
Have you compare the Moser with an standard axle item :-
Length ?.
Spline length & diameter ?.
How does the LSD side gear mate to the axle spline ( Does it feel right ) ?.

4/- "This is the first time the driveshaft has ran since I've owned it" ( driveshaft )
Has it been shipped to you ?. - ( unknown transit damage / abuse ).
Front yoke ?.
The bronze bush in the back of gearbox rear extension housing ?.
Universals ?.
Lost a balancing weigh ( fallen off / knock off ) ?.
Someone dropped the shaft on concrete and hasn't said anything ?.

"We bring the car back to the shop and put it up on jack stands. We couldn't get it to make noise until we got to 3rd gear. As we go higher into the rpms is gets louder".

To me this is starting to sound like an balancing issue = driveshaft ?.
And that maybe ? Pinion & ring are coping with a certain amount of misalignment then at a higher RPM there protesting ?.

At this stage of the diagnoses , I start the process of elimination.

1/- Conduct the same test ( this is your base line to work from ) = ( "We bring the car back to the shop and put it up on jack stands. We couldn't get it to make noise until we got to 3rd gear. As we go higher into the rpms is gets louder".).

Call this Test 1a(free) :- With suspect driveshaft = Results As stated.

I'm presuming that the driveline is free wheeling in the air with no car weight,load or resistant ?.
If this is the case then other base line to work from is needed-
As above but with brakes applied to simulate load and resistant on the driveline.
Call this Test 1b(loaded) :- With suspect driveshaft = Result ??.

Then proceed with the an known driveshaft ( out of an runner ) withTest 1a(free) & Test 1b(loaded) = Result ??.

The Results will determine if the driveshaft is indeed suspect, if not move on to the 3rd member.

Keep us updated.

Cheers the old boy.

dbragg

iTrader: (7)

old rx7- thats a good idea. i daily drive an 85 GSL so the whole driveline from ti will interchange with the SE driveline in the SA. first, ill swap driveshafts and see what happens. if the noise is still there ill either swap 3rd members or get another known to be good third member.

i dont completely understand your description of test b. are you saying run the car but apply small pressure to the brake pedal for resistance?

the axles were built by moser to exact GSLSE spec. they fit in exactly as the GSLSE axles i pulled out did. everything on the axles is brand new.

in your statement to the out of alignment remarks. we did notice something else but i believe the two problems to be of seperate origins. when the car was on jackstands running my neighbor noticed that the wheels were rotating exactly correct. its a very small amount but you can notice it if you look. i ran the car with the wheels, just rotors and with bare axles. here are the results from that problem:

you could see improper movement of the wheels with everything on
with the wheels off and just rotors, youd see impropermovement of the rotors
with bare axles everything looked to be fine

after talking this over with some more knowledgable sources at this weekends DGRR meet i havecome to believe the movement is from the studs on seated in correctly yet. the rotors have to be tapped on with a rubber hammer. it was suggested to me to drive the car and every so often tighten the lug nuts. the problem should works itself out.

could this movement be causing the rearend to make noise? i assume no since the noise is load sensative; hills, throttle, etc.

my next step is tested the backlash with some paint. where do i need to apply the paint? i assume put it on the teeth of the pinion. ill be performing this test tonight and posting the results either tonight or tomorrow morning. if it shows well ill drive the car some more to try to seat the studs better and then swap driveshafts next weekend.

OLD RX-7

" i dont completely understand your description of test b. are you saying run the car but apply small pressure to the brake pedal for resistance? " =

YES, give them a good push make her work!

dbragg

iTrader: (7)

haha, ok. ill give that a try also. ill post the results of the on coming tests as i get them accomplished.

dbragg

iTrader: (7)

im back to trying to solve this. tomorrow is the day i slay this dragon. ill initially try swapping in my known good driveshaft from my GSL. after that, the GSL 3rd member is going in.

MattG

iTrader: (2)

I too have been hearing a sound on mine, If I can narrow down mine I will let ya know what I find

If I stay in TX, Ill prob have the TII at Deals Gap, if I move to Tenn it will just be the LE

dbragg

iTrader: (7)

well i tested it today with a known good driveshaft, didnt fit it. i didnt have time, or enough roya purple to swap the rear chunk. the next time i go to my parents ill be swapping in the GSL chunk.

dbragg

iTrader: (7)

where can you get the bearings for the diff? i cant find them on mazdatrix

steve84GS TII

Way cheaper than the dealer or Mazdatrix.
Napa also carries Timkins,but they were out.
Same number as the factory bearings,except made in Germany.....my favorite kind.
Carriers on the left,pinions on the right.


And a link in case you need it......
https://www.rx7club.com/1st-gen-archive-71/drivetrain-how-rebuild-your-lsd-711948/

dbragg

iTrader: (7)

wow. youre the man. i guess ill just swap mine out with my GSL. if i get the time, i MIGHT try to rebuild the SE diff. it might be a little more than i can handle/have tools to do. thanks steve