TallgeeseIV

iTrader: (1)

I changed my differential fluid from whatever was in it, to Royal Purple 75W-90, and replaced the rtv gasket the last owner did with an actual gasket, and now I've got a REALLY obnoxious and loud whirring noise at speeds over about 30 mph. Doesn't change with turning, and get's louder or quieter with speed and deceleration. Also doesn't do it unless I'm on the gas. It's a 10-bolt with a Thunder Racing 4.10 gear kit and diff cover. I don't know what the problem could be, any ideas?

Also, this cover has these clamp looking things on the right and left of the inside. They look like the threaded part and wobbly feet from a c-clamp. I figured they were for putting pressure on the diff internals for some reason but I didn't mess with them. Is it possible that they're the cause since the rtv and the gasket may be different thicknesses?

EDIT: I DID make one mistake that I just remembered to post. I thought it was full after 1 quart so I put the plug back in and test drove it. It wasn't making any noise so I put it in the garage for the night. I went to leave for work today and got about 3 miles down the road when the noise started after getting up to highway speeds. I turned around and came home at speeds no higher than 40, again, about 3 miles. Went and tried filling it more and it did take another quart, but the noise is staying now. Did I wear out the bearing that easily?

MidwestChassis2

iTrader: (1)

What diff unit do you have? If it is a clutch posi I didn't see the mention of a posi additive and I wouldn't suggest synthetic with a posi either.

As for the cover yes you should back those out during removal and then tighten them back up once the cover has been properly installed.

TallgeeseIV

iTrader: (1)

Didn't realize there were more than one 10-bolt. It's factory, on a 2002 CETA, M6, so whichever that has, I really don't know. Also, 5 different sources that I checked stated that you don't need the additive for Royal Purple so I didn't add anything. Also, the car has 115k miles, and the diff gears have at least 92k on them. Should I have used 75W-140 instead maybe?

Also just went out and tightened those down and took it for a test drive, problem still exists, so that wasn't it. I just don't understand. I didn't mess with any of the internals. I did exactly what people on this forum suggested. It's filled with almost 2 quarts and it isn't leaking. I suspected I might have a bearing that was starting to go, and I realized I had never changed the diff fluid so I changed it, and now I'm thinking that actually made it go sooner...

guppymech

iTrader: (7)

You can try loosening the girdle cover load bolts to see if the whirring noise goes away. The torque spec for the load bolts is 60 INCH LBs max. I would bet you have them too tight. Check out these TA Performance girdle cover instructions (should be good for your cover too).
http://www.taperformance.com/PDF/Rea...structions.pdf

Rob WS6

iTrader: (16)

You ran it low on fluid and most likely starved the bearings of oil. The damage is done, no amount of oil is going to fix it, its probably time for a rebuild.

TallgeeseIV

iTrader: (1)

Damn.... yeeeeaaah, I hand tightened them, way over 60 inch lbs.... i really hope that was the problem. I'll find out tomorrow. Gotta find a small torque wrench, my big one would never fit up in there.

I should mention that my cover was so caked in grease that everyone i showed pictures of it to thought it was stock (including me) until i cleaned it off with brake cleaner.

Also, less than a quart drained out of it. I find it hard to believe that it was ok with half a quart after leaking over the years then replacing it with the same amount of new oil damaged it beyond repair... i did overtighten the bolts, and i pray that was the issue.

New question though. Did i crush the gasket? Do i need a new gasket and another 2 quarts of 75W-90? ($50 in materials essentially...)

Rob WS6

iTrader: (16)

The gasket is fine. If you can drain the oil and keep ur free from contaminants, I don't see why it would hurt to reuse it. But you don't have remove the cover to loosen and re-torque the pre load bolts... The 10 bolts that hold the cover on aren't torque critical, just the two preload bolts. Just loosen the two jam nuts, torque the two hex heads to 5 dt/lbs then tighten the jam nuts with a wrench while holding the hex in place.

guppymech

iTrader: (7)

You mention your cover leaking, the load bolts on girdle covers are prone to leaking. I found some sealing washers that stopped the leak on my 10 bolt TA cover, here's a link to that thread. https://ls1tech.com/forums/gears-axl...l-washers.html

TallgeeseIV

iTrader: (1)

I never actually saw it leaking, but all that grease on it had to come from somewhere, and a lot less than 2 quarts drained out of it, so I'm assuming it had been leaking slowly for a long time. Doesn't seem to be leaking now though. I attached before and after cleaning photos.

guppymech

iTrader: (7)

^^^Your cover is made by TA Performance, they make them for other companies to sell with their name on them. Moser's girdle cover is a rebranded TA also.

TallgeeseIV

iTrader: (1)

So I just tried torqueing all 10 bolts and the 2 preload bolts to 5 ft lbs... no change... how much should i expect to pay a shop to fix this...?

TallgeeseIV

iTrader: (1)

Can anyone tell me if it's even safe to drive? I have work everyday next week and won't be able to get it into a shop until Wednesday at the earliest... Also, can I replace the bearings with ones from a 7.5 rebuild kit or do I need to find the exact ones that came with this 4.10 gear kit in the first place? I was going to buy this one from rockauto: Part#: SDK320C

guppymech

iTrader: (7)

If you toasted the gears they'd make a whining sound while loaded or coasting and may quiet down in the transition between the two. If you have a constant whirring no matter what throttle position that increases the faster you go it's probably the bearings. Since it was quiet with running it low on oil like before you changed it, best case is the load bolts ruined the carrier bearings. Worst case is you need bearings and gears from running it low on oil. The shop you take it to will get the correct bearing kit, there's no special kit for the 4.10s. Only thing special you may have is a solid pinion spacer.
Not sure how far I'd drive it.

TallgeeseIV

iTrader: (1)

It doesn't whine at all while coasting, even in gear. It only whines while i'm on the gas. I was going to order a full bearing kit myself and have it overnighted. Even with the extra shipping charge it's only $150, which i'm sure is still much cheaper than parts from the shop. My performance shop is about 5 miles away with very few lights and mostly downhill, i think i can get it there gently enough. I'm just going to get a rental car for work. Still, any idea what the average labor charge should be?

guppymech

iTrader: (7)

From the noise you describe you're going to need a new ring and pinion. Gears that whine from improper setup can last a long time but burned gears from low oil will fail quickly. You're probably looking at $300-$500 for labor plus whatever the parts cost.

TallgeeseIV

iTrader: (1)

Ugh... there's nothing i hate more than spending $800+ having work done and not even getting a performance increase out of it... this is the worst. I guess i'll take it in and see what they say when they open it up. What brand 4.10 ring and pinion does everyone recommend?

and before anyone says to just get a moser or strange. I really can't spend more than a grand or so on this.

TallgeeseIV

iTrader: (1)

So, I got the car back from the shop on Friday. Took 11 days and $2,000 to fix everything wrong with it, although not all the problems were related to this. Got new axles, wheel bearings, a new carrier, ring and pinion, and all bearings/shims replaced.... and it's STILL making noise! Although it's a different pitch now, and not as loud. It's also doing it during accel AND decel now... So what does that mean? My shop was stumped. They told me it should be safe, and to drive it for a few days to see if it goes away as all the new parts wear in. If not, i should bring it back. But still, i'd like to troubleshoot it right away if i can.

blackandgold

iTrader: (2)

$2K on the 10-bolt...ouch...if they said to give it a few miles and are willing to warranty their work, go that route. You're already in way deeper than most would be willing to go on a 10-bolt. A complete used unit would be like $200, I literally scrapped mine and there was nothing wrong with it.

TallgeeseIV

iTrader: (1)

Yeah... It took so long because as they took it apart, they kept finding more and more bad parts. If I had known early on it was going to end up costing $2,000, I would have gone that route, or more likely just ordered a 12". But all the parts and their labor are under warranty, so one way or another this issue will be fixed.