Rear end oil change

[mvel]

Had my stock ring and pinion changed to a 3.56 last year. I was told to change the rear end oil at 2500 miles after installation.
Questions --
1. Is this really necessary?
2. If so what is the best lubricant to use?
3. Anybody in the N Dallas area best qualified to do this.

 

[RAYSIR]

They even call for the fluid to be changed on new cars at a short first interval. The gears are set up tight to wear in a pattern and they produce more metal when new and that stays suspended in the fluid. The fluid called for is a GL5 75w-140 synthetic with 4oz. of positrac/friction modifier. It doesn't take a Viper tech to change the oil.

 

[2000_Black_RT10]

In addition to RAYSIRs advice, as said, all gears wear a bit of metal until the ring and pinion mesh together after initial use. Those fine particles will float in the fluid and will get caught and compressed between the teeth and will cause pitting, which will then cause whining gears. Every new vehicle we've owned, first thing I do is change the diff fluid after 1500 - 2000 miles. I guess an analogy would be taking 2 pieces of rough steel, rub them together under force and friction and they will become smooth and polished on the contact surface, yet in this case your dealing with multiple surfaces of angled teeth rubbing together and no fluid filter.

 

[FE 065]

You can buy a little suction device at the discount auto stores for $5. It's like a big syringe. Just **** out the old lube like a dealer'd do, and replace it with new.

What size allen wrench etc do you need to undo the drain plug? Anyone remember?

I used 6'-8' of harware store 5/8"OD clear tubing inserted into the diff, running out to the rh side thru the pass side suspension and rear tire, with the end conveniently wedged under the pass side door button finger hook (with a clean rag protecting the door area) to refill my diff after the 3.55 install. The funnel was inserted up at the door end then.

Looked crazy, but worked GREAT!

 

[Copernicus]

I just changed mine and can tell you the fluid is THICK. If possible, try to warm it up a bit with a short jaunt arount town before trying to extract. It will make things a lot easier.

 

[mjorgensen Woodhouse]

Sucking the fluid out will NOT get the metal you are seeking out. To do this properly you need to drill and tap the housing to install a proper drain plug. We do this with every diff fluid change that does not already have a drain installed.

 

[VIPER R]

Where do you drill?, lowest possible point.

 

[ViperTony]

There's a writeup on installing a diff drain plug in the How To section. FYI.

 

[RAYSIR]

Sucking the fluid out will NOT get the metal you are seeking out. To do this properly you need to drill and tap the housing to install a proper drain plug. We do this with every diff fluid change that does not already have a drain installed.

Yeah, forgot that. I use a 1/8 pipe tap and then 1/8 pipe plug. Drill and tap at lowest point. Don't overtighten and strip it.

 

[FE 065]

Agreed, the metal probably won't come out completely just by sucking the lube out, unless you drive the car just prior and get everything stirred up into suspension.

I've seen Tom's how-to on installing a drain plug. I asked the guy who installed my gears about the idea of drilling the diff there and wedging a pipe plug in the hole which puts some outward pressure on the surrounding metal.

He didn't seem to hate the idea, but we kind of agreed that it might be better to have something more like a oil drain plug arrangement that simply screws into a threaded insert in the diff.

 

[RAYSIR]

I've seen Tom's how-to on installing a drain plug. I asked the guy who installed my gears about the idea of drilling the diff there and wedging a pipe plug in the hole which puts some outward pressure on the surrounding metal.

He didn't seem to hate the idea, but we kind of agreed that it might be better to have something more like a oil drain plug arrangement that simply screws into a threaded insert in the diff.

Duh, think about this. What??? Show me the problem or any effect of the pipe plug that was a problem. Yeah, a pipe plug is designed to put pressure on the surrounding metal, that's what keeps them from leaking. Sure like to hear from the guy who installed your gears. But it's Okay for a threaded insert? What's the pipe plug? a grenade? ( Heh, hun would you fill up my whiskey? Please???) LOL

 

[SweetRed04]

My '04 has an drain plug from the factory. I changed the fluid at 18,000 as specified in the service schedule.

Rear ends ARE NOT set up "tight". They are build with a specified amount of backlash (free play between the pinion and gear). You can feel it if you grab the driveshaft in neutral and twist it back and forth.

Hypoid gearsets (rear end gears) do "lap in" but the wear is almost impossible to measure - it takes special gear measuring equipment or a CMM.

The biggest change is in surface finish - and it is subtle if the gears are made well.

On these gearsets, the teeth deflect elastically, in the range of 0.010 mm, to widen the pattern to spread the loads.

The reason the factory rear ends need frequent, by typical automotive standards, is due to the internal oil pump system the operates the differential lock.

Normally rear ends are lubed once - the Viper is an exception.

 

[SweetRed04]

Duh, think about this. What??? Show me the problem or any effect of the pipe plug that was a problem. Yeah, a pipe plug is designed to put pressure on the surrounding metal, that's what keeps them from leaking. Sure like to hear from the guy who installed your gears. But it's Okay for a threaded insert? What's the pipe plug? a grenade? ( Heh, hun would you fill up my whiskey? Please???) LOL

The factory uses a sealant on their drain plugs.

Furhter, there are press fits all over in any modern machine.....

 

[dave6666]

Wonder why the block doesn't crack from the 2 pipe plugs in it for the coolant drain...

 

[FE 065]

The guy that did my gears also does all of Ford's diffs for the new Shelbys. Which is why my diff was down there for 2 weeks waiting its' turn.

It wasn't a huge deal, we were just talking about installing drains plugs. If someone had their diff out and had a choice, it might be better to use something other than a pipe plug wedged in there seeing as the edge of the diff where it meets the cover is relatively nearby. Drain plugs in a block usually aren't that close to an edge, so there's less chance of one starting something that turns into a crack.

I'm just offering something to think about for anyone planning on installing a drain plug. None of those drain plug installs have cracked the housing yet but..


- Better over engineered than under engineered ?

 

[VIPER R]

My '04 has an drain plug from the factory. I changed the fluid at 18,000 as specified in the service schedule.

Rear ends ARE NOT set up "tight". They are build with a specified amount of backlash (free play between the pinion and gear). You can feel it if you grab the driveshaft in neutral and twist it back and forth.

Hypoid gearsets (rear end gears) do "lap in" but the wear is almost impossible to measure - it takes special gear measuring equipment or a CMM.

The biggest change is in surface finish - and it is subtle if the gears are made well.

On these gearsets, the teeth deflect elastically, in the range of 0.010 mm, to widen the pattern to spread the loads.

The reason the factory rear ends need frequent, by typical automotive standards, is due to the internal oil pump system the operates the differential lock.

Normally rear ends are lubed once - the Viper is an exception.

I guess the Quaiffe falls into the once is good enough.