Differential Service/Drive Shaft R&R Walkthrough

Hey guys, Bob(previous owner of my 95, aka dbobo) came by my place today for a Diff service and to get a "rebuilt" drive shaft installed into his 98 Base so I thought I'd take tons of pics and give you guys a write up on the job(s). Here it goes........



First off, the shaft came out of Max's 98 Base and has low miles on it(Max got a MMX shaft), so I sent it out to the local shaft shop, DriveLine Services, and had it gone through. They replaced both u-joints, straightend and balanced it(15k rpms). The shop can also replace/rebuild the rubber inserts if there is any vibrations. The repair to Bobs new shaft was $94 bucks delivered with a 24hr turn around.

Next, the 98 has 87k on it and the diff. hasn't ever been serviced as far as he knows so I figured I'm right there so its time for a service.

A standard swap WITH air tools should take the average at home mechanic NO MORE than 2 hours, I did it in just about 1...maybe a little less.(Note times of pictures, I did the shaft first, and than started the diff service)

Here are the tools you'll need for the drive shaft swap....



Air Impact Gun(or equivalent hand Ratchet)
12" 3/8" extention
13MM Wobbly Socket
Long Flat Head Screw Driver
Long Pry Bar(29")
1/4" Ratchet and 5/32" socket w/6" extention for fuel tank hose clamps(or small flat tip screw driver if you can get to them)
12MM 12 POINT Ratchet Wrench
13MM or bigger Open end Wrench for double wrench leverage technique(DWLT, lol, I'm making up sh*t now)
Marker or equivalent for making shaft for alignment
Lock Tite for drive shaft to pinion flange bolts

Last but not least...safety glasses to prevent this..........


Or this...........LMAO



Ok.....start by jacking the back of the vehicle up as high as safely possible and place jack stands underneath and rest the weight of the vehicle on the stands. Remove the jack for later use to support the fuel tank. I placed the jack stands on the lower control arms because my stands sit snugly inside the drain holes where the stock air springs sit. Make sure if your car still has the factory air, you turn OFF the air ride switch IN the trunk. Bobs car was converted(by me).

Next you'll want to remove the drive shaft bolts using the 12mm 12 POINT Ratchet Wrench with the 13mm open end, using the double wrench method.


You may have to release the parking brake and place the car in Neutral to spin the driveshaft, you can also use the long flat head screwdriver to stop the driveshaft from spinning by placing it in the u-joint. I was able to get access to all the bolts without turning the shaft.


Once you've removed all the shaft bolts, the next step is to remove the fuel tank straps(different than pictured above but easier to remove the shaft bolts with the tank up). Start by removing the rear(of the tank/car) 13mm strap bolts using the impact gun with the 13mm wobbly socket and 12" extention. The tank won't fall to much so no worries.

Passenger Side Strap


Drivers Side Strap(notice the exhaust pipe at the bottom right)


*******These next steps were required on Bobs, but NOT on my 95, nor Max's 98. I was able to remove the shaft on both of our cars without removing BOTH straps completely. I would suggest seeing how much movement you get when remove just the back(of the car) bolts/straps on the tank. The back of our tanks rested on the exhaust and with some cohersing our shafts came out, it was tight, but saved a HUGE amount of time, IMHO.********

Next you'll want to place the jack underneath the middle of the gas tank and raise it so it slightly puts pressure on it. Now remove the front(of the car) 13mm strap bolts and move them out of the way.

With the weight of the tank now on the jack, you'll want to loosen the hose clamps on the fuel filler tube(both fill/vent hoses) and remove both hoses. I used a long pry bar for leverage to remove the hoses.


Next you lower the jack and the fuel tank down about 6-8" which is plenty to remove the shaft. Make sure if you have a FULL tank, that you don't go so low as to dump gas out of the fill/vent tubes.



******continued if you didn't have to remove ALL the straps and extra steps needed to lower the tank more.********

Now that the tank is lowered out of the way, you'll want to remove the middle drive shaft "loop" just in front of the gas tank. Also 13mm bolts so use the 13mm wobble/extention/air gun setup.


Move back to the back of the car(I know, back and forth, but this saves your knuckles from falling shafts) and remove the rear drive shaft loop while holding the shaft with your other hand. These are 13mm bolts also.




Now, place a drain bucket underneath the tail shaft of the transmission because when you slide the shaft out, you may get some ATF dripage and you don't want to make a mess. On the 4 shafts I've swapped, NO fluid came out of the tail shaft, but a little came out of the input yoke on the shaft when it angles down when you slide it out.

Go back to the rear and slide the shaft out.......



Here is a comparison showing the old shaft next to the "new" shaft(they even polished the shaft, nice of them). Notice the gaps on the bottoms of the shafts where the "tube-in-tube" design is pieced together. A ONE piece shaft will be filled in.



****My old two piece next to my used one piece...notice NO gaping hole?****


Now that you've removed the old shaft its time to install the "new" shaft. First you need to locate the paint marking on the output shaft.....


Next locate the "notch" inside the input yoke of the shaft and mark the outside of the yoke with the marker you have set aside.


Now, line up both of these marks when installing the shaft into place. Before you start tightening that bolt in your hand....FIRST put a touch of Lock-Tite on each of them....


Tighten them using the double wrench method with a reasonable amount of force, single wrench isn't going to be enough(unless you're a buff man argggg*rips t-shirt in half*, haha) so double wrench it and save your back, and you're "o-ring"(for those old timers still wrenching, lmao).

Reverse for installation, and the only concern is to install the fill/vent hoses BEFORE you completely tighten the fuel tank straps or you'll have to bend/force them into place. I placed them on the tubes and than slid them on completely once the straps were tight. Also....after the shaft change, MAKE SURE you double check your transmission fluid just incase you lost some.

Next I'll walk you through a standard differential service. Start by using the ABOVE method and raise the back of the vehicle and support it properly.

Here are the tools you'll need for this service....


Air Impact Gun
Air Ratchet, 3/8"
Standard 3/8" Ratchet
Standard Flat Head Screw Driver
Flat Paint Scraper
15mm Open End Wrench
18mm Deep Socket
22mm(13/16") Deep Socket
13mm Wobbly Socket
Safety Glasses
Brake Cleaner(ahhh my eyes!)


First you're going to remove the 22mm(13/16") nuts holding the rear diff mount to the rear subframe. You'll need to hold the bolt on the top of the subframe using the 15mm Open end wrench.




Next you want to remove the VENT TUBE at the top right(passenger side) of the diff cover. Place the drain bucket under the diff and using the Air Ratchet and the 13mm Wobbly socket remove all but one(or two) bolts in the diff cover, this will allow the majority of the fluid to drain without the cover flying off in your face.
(NOTE the vent tube)


Once all the bolts are removed, use your flat head screw driver and pry gently on the little tabs on each side of the cover, while keeping your other hand on the back of the cover to steady the pressure when prying.


Once the fluid has drained, remove the cover and inspect the diff. There will be some pitting and "cracks" in the ring/pinion/spider gears, this is normal. Anything excessive is bad, and you'll be able to tell the condition of your diff based on the amount of metal in the fluid, and on the magnet. This is a 87k mile diff with possibly its first service.



Next step is to clean all the gasket material(silicone) from the diff and the cover. You want to place a rag inside the diff to prevent anything from going inside.



Make sure you use your fingers to "scrape" out the fluid in the bottom of the diff, this will prevent it from running out when you're trying to re-install the cover. The gear oil will prevent the silicone from properly sealing. Use SOME brake cleaner on the inside of the diff, but mainly just the outside sealing surface.



Here is how you properly open a tube of Black RTV Silicone, LMAO!(I just put this in for sh*ts and g*ggles)


When cleaning the diff cover, MAKE SURE you clean all the old silicone out of the little grove using a small screw driver. Apply a 1/4" X 1/4" bead of silicone around a nice clean cover surface, again using brake cleaner to clean any deposits off/in it.


Next step is to CAREFULLY place the cover back onto the diff using CARE to not smear the silicone upon installation. Make sure you have the bolts handy to start them all while holding the cover. Once you've started the bolts, use the Air Ratchet/13mm Wobbly socket to tighten one bolt. Now you can take your hand off and tighten the rest of the bolts down, I tighten them to the strenght of the air ratchet and give it a tiny turn(using the air ratchet as a ratchet WITHOUT pushing the button) to torque it down.

Now you want to clean up your mess by taking your finger and whiping all the access silicone off.


Now the tiring fill process. Using a standard 3/8" ratchet, remove the fill plug and clean the magnet on the back of it. I use this filling method because most pumps you get will leak after the first use and be USELESS! Buy Qts of 80w90 gear oil and attach a hose to the end of the nipple and turn the bottle upside down to squeeze the fluid in. Slow and tiring but clean and easy and no extra cost.



Keep filling(should be about 2 qts or less) until the gear oil start pouring out of the fill hole. Pull the hose out and let it drain until its slows and insert the drain plug. Since you still have the rear diff mount removed you'll want to re-attach it, lower the car and check the fluid on level ground. This would be the "proper" way, but due to the fact that the car was 3 feet in the air, the angle of my diff W/O the rear mount in place was about right, so I called it good. Use common sense.


For those of you that don't know how to read the tag on a diff...here is what I know, the bottom line has all the info on ALL(or most) tags.

3.07 is your gear ratio(3.27 on an LSC) and the 8.8 is the "model" of the carrier assembly.


Tadaaaa in 2 hours you've just performed some general maintanence and upgraded your vibrating drive shaft. YAY!

Damn you Serge...I KNEW someone was going to post, lol. Just regular Valvolene 80w90....its no hot rod.

Haha, my bad for ruining the continuiety of this thread. I fixed it though. I recently did a diff service myself... well actually I just took it to jiffy lube, I brought my own fluid. Amsoil Severe Gear 75w-110... it's really good stuff and is good for 50,000 severe miles (racing, towing, etc) or 100,000 normal usage miles.

Jiffy Lube?! *cringes and gets chills* :embarrassed: haha!

Thats cool that they changed it using your own fluid....or did they? :err-what?:

Yea, they did. I asked them to give me back my old Amsoil bottles and one of them had .2 quarts left which makes sense since the diff takes about 1.8 quarts. Cost me $33 labor which is not bad at all.

Thats a pretty decent deal, but its also VERY easy to do.

Nice write up Jesse.

I can almost smell that gear lube.

I hope your eye is OK!

nice job Jesse, as a footnote, on the way home I may have exceeded the speed limit a tad,lol, nice and smooth, no vibration.
How can you work with one hand holding the camera?

Jesse... LMAO about the goggles I was going to post about that but you put that nasty pic in there.

Great write-up as always . Still no bottle pump?? that thing works really well and only costs $ 8 yo!

Very interesting to hear that the gen 2 shaft can balance out. Cheaper than buying a $500 MMX shaft.

I just opened my windows and got out a new air freshener, hate that gear oil smell. Nice write up.

Thanks Guys Yeah, gear oil....eww, my garage still reeks of it. My eye is healed now, those happend last year, 5 stitches to my eyelid from a gas tank heatshield that smacked me, and the one under the SAME EYE(happend about 4 months later, lol) was a socket flying off a universal(my wobble adapter broke) when I was trying to use the airgun with my left hand. I'm always carefull and clean when I work, but at that time I was going through some very very tough times so I really wasn't "there" when I was working.

Max.....you mean the bottle pump we tried to use and broke the first time we tried to pump it? I've bought about 7 different types over the 10 years of working on cars and the only one thats been worth a crap so far was the 5 Gallon Bucket Pump at the shop....and that one even leaks like a siv all over the place, but it pumps good, haha.

Bob....you speed....never, haha. I'm glad that worked out, I know if the shaft needed more work the shop wouldn't have given it back, those guys are great. For those of you who are curious, if the rubber was bad, they'd disassemble the shaft and replace that too. I'm sure its way less than an MMX

J, are you saying this driveshaft shop can balance the stock two piece well enough that it won't vibrate at freeway speeds even with gears?

Yep, if they can't balance it with the "stock" insides, they'll rebuild it.

Kudos J.

Those eye pics brought back memories. ROTFL

Yes kids, safety glasses are cool!

Thanks

Oh yeah! I forgot to mention, I made this walkthrough my 500th post I earned that 3rd star and Jr. Associate title! :cool-blue:

Don't you WORK???? 500 in the short time tour been here???? That's about 50 a day, isn't it?

Kidding aside....we've seen a flash of genius in those 500...keep up the good work. And that goes to all the 'newcomers' that followed J here!!

budpytko said:

Don't you WORK???? 500 in the short time tour been here???? That's about 50 a day, isn't it?

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Honesty Bud....nope. Haha! I quit working for my good friends that own a transmission shop because they struggle during the winter, so I stopped working for them full time so they wouldn't "go under". I don't have very many bills so it was "kinda" easy for me. That, and the fact that I finished the hiring/background investigation process for the California Highway Patrol(long freaking time applying:mad-tilt and now I'm just waiting for the next OPEN class. Just killing time......

budpytko said:

Kidding aside....we've seen a flash of genius in those 500...keep up the good work.

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Thanks, thats the nicest thing someones said to me in a long time! :love-it: I look at all of you as friends so I really appreciate that comment. Honestly thats the only reason I post on here(or anywhere), knowing that I helped one person today makes me feel good about myself.

I'm glad you guys are enjoying my company since I joined(or came back), and I WILL keep up the good work, if I don't, just slap me, hehe. :big-grin: Thank you!