: The Inevitable... I believe it's differential time. Advice please!



WarrenMRogers
03-08-13, 03:25 PM
Well it has been whining for the last 25k miles or so, and now I'm at 99,1xx and it's beginning to make a rubbing noise (?) when I turn tightly. I'm going to go ahead and say I need to fix something.

From what I've read, I believe I'm due a differential. I am having ZERO luck searching online for options other than a $4,600 creative steel solution which is a) out of my price range and b) unnecessary for my purposes.

This is my DD and it is mostly stock. I intend to put exhaust and cold air intake on mostly for the sound, and perhaps tune it but that's it. I do not intend to supercharge it or tear into the block (unless it blows up). I may do some minor suspension mods and a short throw shifter--but you get my point, nothing too serious.

What are my options? I hear all this talk about '07 rears but I can't find anything online. Is there something I'm missing? Where should I look and what should I expect to pay? Is this something I can do myself with intermediary knowledge/skill and basic tools? I have a floor jack and jack stands but no lift.

Thanks!

darkman
03-08-13, 03:33 PM
First of all, noise during tight corners is the signature of noisy limited slip clutches sticking during separation (to allow the wheels to turn at different speeds). If that is the noise, the remedy is fresh fluid and/or an increase in the amount of additive.

If in fact you need a new differential I would start by finding out Luke at Lindsay Cadillac's delivered price for the current version (which all any dealer will have.)

WarrenMRogers
03-08-13, 03:55 PM
Ok, differential fluid eh? I'll give that a whirl. Any advice on brand/type of additive? Excuse my ignorance but I am not hip to differential repair/maintenance.

darkman
03-08-13, 04:14 PM
I would run Amsoil Severe Gear which has the additive already in it. You should get a bottle of their additive anyway because some individual differentials can require more additive to operate quietly.

The latest GM fluid now has the additive already in it but the cost is high.

pato
03-09-13, 02:53 AM
Redline gear oil has additive in it as well.

WarrenMRogers
03-09-13, 04:06 AM
Is this something I can do easily or should I consult a mechanic?

silentwig
03-09-13, 07:41 AM
Is this something I can do easily or should I consult a mechanic?
Very easy. It doesnt say, you may have to adjust your exhaust out of the way. I have magnaflow catback and needed to drop part of it to fully access the fill plug. Make sure you warm your diff up before you change fluid.
http://www.cadillacfaq.com/faq/answers/difflube/index.html

rand49er
03-09-13, 08:52 AM
Very easy. ...


Is this something I can do easily or should I consult a mechanic?It's very easy if you're mechanically minded, but if you've never done this kind of thing or don't have any tools, ramps, or containers to drain the fluid into, just take it somewhere to have it done for you. It won't be very expensive.

WarrenMRogers
03-09-13, 12:13 PM
I can probably do it based on this youtube video I just watched: http://www.youtube.com/watch?v=rNdHmpQQJJQ I have factory exhaust and it's going to be 62 degrees today so I'm going to give it a shot. Hopefully I can get a decent fluid and the appropriate pumps at NAPA or autozone. He suggests taking the whole cover off and since I am relatively new to the car I think I'll do that to be sure it's completely empty and all. Any tips to keep me from ruining my differential before I get started?

pato
03-09-13, 12:28 PM
There is no need to take a cover off, just a drain plug.
But make sure to loosen the fill plug first so you're not stuck with an empty diff with a fill plug that won't come off.

rand49er
03-09-13, 12:58 PM
^^^ Yeah that. For goodness sake, DON'T take the cover off.

silentwig
03-09-13, 01:19 PM
Loosen up the fill plug before you remove the drain plug.

darkman
03-09-13, 01:20 PM
Loosen up the fill plug before you remove the drain plug.

There is an echo in here.

silentwig
03-09-13, 01:24 PM
There is an echo in here.
http://rlv.zcache.com/i_heart_reiterate_tee_shirts-r141dba1a69ef425d86cd911b8ca07426_804gy_216.jpg

WarrenMRogers
03-10-13, 08:47 PM
I didn't get time to do it this weekend because i was busy getting a new job! Way better Hooray. I'll heed this advice and do it this weekend! Thanks so much I'll post with the outcome when in done.

WarrenMRogers
03-12-13, 01:45 PM
I'm just about to order some Amsoil as I guess you can't pick that up around town. Before I do, I noticed that AutoZone and the like have Mobil 1 synthetic which I saw ls1tech forums referencing. Has anyone used it? It's about $5/quart cheaper and I can pick it up in town. I'd of course include the additive. And on the additive note, I keep hearing additive this additive that but no specific name or composition. Is there something specific I should be looking for or just ask the clerk "Gimme additive!?"

darkman
03-12-13, 02:07 PM
The Mobil1 website says:



Mobil 1 Synthetic Gear Lube LS 75W-90 contains special friction modifiers designed for limited slip-type differentials. In most applications, the addition of special LS (limited slip) additives is not required. For axles requiring the highest level of limited-slip performance, OEM specific LS additives can be added to this fluid.



http://www.cadillacforums.com/USA-English/MotorOil/Images/Tabs/boxNoFade_RightUpper.png



http://www.cadillacforums.com/USA-English/MotorOil/Images/Tabs/box_LeftLower.png
So you may not need the additive, and if you do (still has chatter in slow turns) you can add the GM OEM addiitive. The additive, which the auto parts store may have, is called a friction modifier for limited slip applications.

WarrenMRogers
03-12-13, 02:10 PM
Looks like I have my afternoon spoken for. I'll post the results.

thebigjimsho
03-12-13, 02:27 PM
I'm just about to order some Amsoil as I guess you can't pick that up around town. Before I do, I noticed that AutoZone and the like have Mobil 1 synthetic which I saw ls1tech forums referencing. Has anyone used it? It's about $5/quart cheaper and I can pick it up in town. I'd of course include the additive. And on the additive note, I keep hearing additive this additive that but no specific name or composition. Is there something specific I should be looking for or just ask the clerk "Gimme additive!?"

Some NAPA stores carry Amsoil. The NAPA down the road from Brainerd Raceway in MN was quite stocked with Amsoil...

WarrenMRogers
03-12-13, 02:44 PM
I see, they don't list it on their website anywhere. Perhaps I'll try the store.

barrok69
03-12-13, 05:16 PM
The belle tire near me also carries amsoil. Wouldn't hurt to just walk in and check it out. I didn't realize until after the fact that I placed an order though. lol.