How to change gear fluid

[LaserSVT]

Really the question is more about how to remove my diff cover so I can clean off the seal gunk so I can reseal it. Also at 50K miles I should prolly change it anyway and I need to install the diff cover brace :shrug:
I have access to a lift as well. So do I just unbolt the two bolts that brace the cover then the two bolts that hold the diff to the frame and dissconnect the driveshaft as well as my cat back so that I can drop the pumpkin down far enough to remove the cover so i can scrape off the stuff or can the cover slip off without dropping the diff down?
I was looking at the how to section and got some ideas but didnt see anything about completly removing the cover so you could re seal it :shrug:

 

[ShelbyGuy]

step 1: remove differential housing assembly from car and place on workbench
step 2: remove cover and drain lube
step 3: reseal cover and let rtv gasket material set up for 24 hours [i'm not joking]
step 4: cover the axle holes with duct tape and refill differential housing with gear lube [75w-140 full synth, with friction modifier]
step 5: reinstall differential housing assembly in the car, but don't tighten all the bolts
step 6: install BilletFlow diff brace, and tighten down the hardware.

 

[LaserSVT]

So in addition to removing all the mounting bolts and drive shaft I also have to pull the axles too? I never noticed. Are they just bolted to it or is it like a SRA and I have to get in there to remove the axle clips? Seems like a PITA to do a simple fluid change
And when you say let it setup do I put the sealent on it WITHOUT the cover bolted up and let it cure for a day or do I put on the sealent and bolt the cover up and then let it sit for a day. Also, if I do it like that do I just finger tight the bolts then let it set, then tighten them down to spec AFTER the day of letting it sit?

 

[LaserSVT]

Anyone else?

 

[04sleeper]

Bill,

When I resealed my diff, I didn't remove the axles or housing. I took the cat-back off, took out the lower shock bolts and removed the IRS bolts (I have the low profile ones) and dropped the IRS down. Then I just unbolted the cover and a few things around it to get it out. Like braces and such. (The IRS is still in the way but it will have just enough room to slide the cover out).

I cleaned off all the old sealant with brake clean and used Permatex Ultra Grey to reseal the diff. I let this dry till the next day then I refilled it and put it all back together.

It is not very fun to do but at least it's done.

 

[LaserSVT]

Bill,

When I resealed my diff, I didn't remove the axles or housing. I took the cat-back off, took out the lower shock bolts and removed the IRS bolts (I have the low profile ones) and dropped the IRS down. Then I just unbolted the cover and a few things around it to get it out. Like braces and such. (The IRS is still in the way but it will have just enough room to slide the cover out).

I cleaned off all the old sealant with brake clean and used Permatex Ultra Grey to reseal the diff. I let this dry till the next day then I refilled it and put it all back together.

It is not very fun to do but at least it's done.

What are the IRS bolts? Are they the ones that mount the assembly to the chasis? The same ones that you are supposed to upgrade to 14mm?

 

[ac427cobra]

If you take your driveshaft off, cat-back, remove the front diff support and unbolt the rear diff mount you can slide the center section far enough ahead to slip the cover off.

Did it twice. Not too bad.

FWIW

:thumbsup::coolman::beer:

 

[LaserSVT]

If you take your driveshaft off, cat-back, remove the front diff support and unbolt the rear diff mount you can slide the center section far enough ahead to slip the cover off.

Did it twice. Not too bad.

FWIW

:thumbsup::coolman::beer:

Thanks, that was exactly how I was pitchuring it :nice:
I guess I may just do it myself then. My friends shop said if I bought the fluids and gunk for the seal then he would charge me $60 to do it AND slap in the diff cover brace.
I really prefer to do all my own work but I only have Sundays off so I would have to do it after work on Saturday to let it cure for 24 hours.

Where is the best place to get the sealent? Kevin, you say Permatex? Where can I get that? Autozone, Oreilis, NAPA? And the gear oil I should get something synthetic in like a 75-140. I am also supposed to add 4 oz of friction modifier right?

And thatnks for all the input guys. I wana catch all this stuff before it causes dammage.
I am always all over this car and if I see anything not right i wana get it taken care of right away. Too msny times I see people with high HP cars not go over them regularly and then have some monsterous repair bill for something simple that failed.
You guys have been great with the input and help. Wish I woulda come to this site earlier :thumbsup:

 

[04sleeper]

If you take your driveshaft off, cat-back, remove the front diff support and unbolt the rear diff mount you can slide the center section far enough ahead to slip the cover off.

Did it twice. Not too bad.

FWIW

:thumbsup::coolman::beer:

Wow. Never tried it that way. Sounds a lot easier then the way I did it. :thumbsup:

Thanks, that was exactly how I was picturing it :nice:
I guess I may just do it myself then. My friends shop said if I bought the fluids and gunk for the seal then he would charge me $60 to do it AND slap in the diff cover brace.
I really prefer to do all my own work but I only have Sundays off so I would have to do it after work on Saturday to let it cure for 24 hours.

Where is the best place to get the sealent? Kevin, you say Permatex? Where can I get that? Autozone, Oreilis, NAPA? And the gear oil I should get something synthetic in like a 75-140. I am also supposed to add 4 oz of friction modifier right?

And thanks for all the input guys. I want to catch all this stuff before it causes damage.
I am always all over this car and if I see anything not right i want to get it taken care of right away. Too many times I see people with high HP cars not go over them regularly and then have some monsterous repair bill for something simple that failed.
You guys have been great with the input and help. Wish I would have come to this site earlier :thumbsup:

You can get the Permatex at any of the parts stores that you mentioned. Be SURE and get the Ultra Grey though.

Synthetic fluid should work just fine. (ie. Mobil 1). Also, I added friction modifier that I bought from Ford. :thumbsup:

 

[ShelbyGuy]

takes less time and effort just to yank the whole pumpkin rather than fiddle-farting around with it still in the car. if it takes you an hour to yank the pumpkin, you're just not trying very hard. the 00r brace rolls forward then slides out towards the side of the car. the half shafts and hub carriers/brakes stay together as an assembly. just mark the eccentric so you can preserve your alignment settings.

try this:
http://www.lx.net/jlynch/pumpkin.htm

 

[ac427cobra]

takes less time and effort just to yank the whole pumpkin rather than fiddle-farting around with it still in the car. if it takes you an hour to yank the pumpkin, you're just not trying very hard. the 00r brace rolls forward then slides out towards the side of the car. the half shafts and hub carriers/brakes stay together as an assembly. just mark the eccentric so you can preserve your alignment settings.

try this:
http://www.lx.net/jlynch/pumpkin.htm

John:

You are correct that pulling the halfshafts are not really that big of a deal. I have that job down to about 30 minutes! ;-) Luckily I don't have to change them anymore like I used to! :rolling:

If you do remove the center section from the car it makes resealing the cover a LOT easier. Removing the sealer is a PITA I will fully admit. So if you're doing the center section on the bench it's a lot more comfortable to work on than in the car.

It depends on how you want to attack the project. I grew up work on cars in a Ford service department and working flat rate gives you all sorts of bad habits. I always tried to do the best job I could in the least amount of time.

FWIW

:thumbsup::coolman::beer:

 

[SCT2003]

If the diff is not currently leaking but you want to install a BF brace with some fresh fluid...

Can you just use the stock fill plug to suck the old fluid out and pump some new fluid in???

Does this get enough of the old fluid out???

In addition, I've heard that the process of changing the IRS brace will sometimes bring on leaks when there wasn't any leaks to begin with???

Any opinions on that???

:shrug:

Later...Dave

 

[Jomo1994z71]

my Irs has a small leak...it happens but the oil is pretty thick so it barely leaks

 

[SCT2003]

Had a BF IRS brace installed today along with some low-profile 12 mm rear button head IRS bolts in back and larger 14 mm IRS bolts up front. Had my mechanic pump out the old diff fluid (which looked pretty clean after 15,000 miles) from the fill hole. He refilled it with almost 2 liters of Motul 75-140(with friction modifier) gear oil by pumping it in. Once it started to leak out the fill plug, he knew it was full.

If you decide to use a manual pump to remove and refill gear oil like he did, make sure you use the largest tube possibe on the pump. Since the gear oil is so thick, small hoses will take forever to pump the fluid out and in.

I know Motul gear oil is probably overkill for my street car but what the heck, the blue oil matches my car...LOL

:beer:

Later...Dave

 

[707svt]

Bill,

When I resealed my diff, I didn't remove the axles or housing. I took the cat-back off, took out the lower shock bolts and removed the IRS bolts (I have the low profile ones) and dropped the IRS down. Then I just unbolted the cover and a few things around it to get it out. Like braces and such. (The IRS is still in the way but it will have just enough room to slide the cover out).

I cleaned off all the old sealant with brake clean and used Permatex Ultra Grey to reseal the diff. I let this dry till the next day then I refilled it and put it all back together.

It is not very fun to do but at least it's done.

I did the samething you did. When you put the seal on go light all the way around and spread it with ur fingure dont over do it cause it will leak again that way. I did mine and hasent leaked, theres better contact go n thiner. Oh ya and change ur fuel filter while ut down there.

 

[tjs98gt]

damn, i brought my car into work today because my diff is leaking. i really dont feel like doing it at all. its such a pain in the ass and one of the reasons im going back to solid

 

[SilverCobra7]

Reviving old thread!:shrug: I've been holding off on changing my differential fluid cause its so tight back there... But as SCT2003 has done, I'm thinking of just pumping out the old fluid and pumping in new one. No leaks so don't want to mess with it... Will I be alright?

 

[earico]

I drill and tapped a 1/4" NPT plug into the bottom of the carrier for a friend. This was something Jimmy did and suggested. Worked like a charm. It's better than pumping it out because it will get all the fluid off the bottom.

Drilled the hole, tapped threads, sprayed in brake cleaner into the fill hole, let brake cleaner flush out the shavings thru the new drain hole, install plug and fill diff. Whole process took less than an hour.

 

[SVT P-Tree]

I did the same with my diff. Make sure you tap it straight though!

 

[Mr.Venom]

If you take your driveshaft off, cat-back, remove the front diff support and unbolt the rear diff mount you can slide the center section far enough ahead to slip the cover off.

Did it twice. Not too bad.

FWIW

:thumbsup::coolman::beer:

I'll have to remember that. :read: