do you think i need to change 9 year old diff fluid? does age effect it? only got 10k miles on it. is there really a need?

 

comon someone has to know?

 

You change your engine oil every period of months or milage since it gets contaminated and breakes down but that is usually mineral oil and since the engine has a lot more 'mix' with other fluids and gasses, it gets nasty.

Since the rear end is sealed you don't get hardley any of the mixing problems so it doesn't really matter. If I had mineral oil in there, I probably would after 10 years but if I had synthetic, don't think that there is an issue since it doesn't break down nearly as fast.

 

Pressure also breaks down the lubrication molecules. As the lube is trapped between the gear teeth in the diff it suffers great stress and breaks down as well. Engine oil certainly breaks down quicker, but I would change the diff lube in a driven car every couple of years max. (Off to check the service schedule in the manual...)

 

Dude.......the more often you change ALL the fluids the better. It's cheap insurance. For me personally:
-engine oil: every 3K miles with Mobil One or some other good semi or 100% synthetic
-coolant: once a year with standard yellow-bottle Prestone and DISTILLED water, NEVER faucet water(very important to change often as acidic coolant will QUICKLY damage the rotarie's seals- it happened to me)
-trans and diff fluid: every 1.5 to 2 years with Neo Synthetic (I live near them and know the owners so they can custom blend different weights for me)
-brake fluid: every 1.5 to 2 years with Neo or comparable brand.

The rule of thumb is that if you are not sure, then change it. If you don't remember when you last changed it, then do it. And even if the car sits most of the time, you know it's probably all nasty; you shouldn't even be asking about having 9 year old fluids

Okee doke, good luck buddy. Take good care of your FD and he'll take good care of you.

Oh yeah, and don't forget the fuel filter, air filter, spark plugs and spark plug wires.

-Tom

 

Forgot to mention that, thanks DamonB. The actual source for all oil changes is breakdown due to pressure and heat. Rear diff doesn't see near as much as the engine and rear diff fluid is usually much more resiliant to then engine oil to break down so your low milage rear end should be cool.

I do agree with TomsRX7, no harm in changing it every once in a while. Very very easy to do with only a few tools and just a little time but big benefits in the long run of the car.

 

For you high mileage FD owners, be aware that switching to synthetic late in the life of a car can result in minute oil leaks, the kind that make a mess around lip seals/gaskets/o-rings but may never put a drop on the driveway. This happened to one of my diff half-shaft lip seals after switching to Royal Purple Maxgear. No oil hit the ground but the mess on the halfshaft and diff housing made changing the diff bushings a nasty job. Changed the lip seals while the diff was out so no more leaks with my slippery synthetic gear oil.

As for trans oils, I have run the Royal Purple, Redline, and Neo. I now use the Red Line MT90 ... Red Line MTL was too thin, Royal Purple 75w90 did not shift well, and Neo is too difficult to get in Houston but it seemed to do fine for the short while I used it.

 

Twokrx7, nice point you made there; you're right. Every time I put synthetic in my trans, I get leaks. And NOT severe ones that leak on the ground, just minor seapage that every once in a while (when I had the car jacked up) I would have to wipe the tranny down with a paper towel.

In my opinion, I think it also may be that synthetic gear oil has more aggressive detergents in it that are intended to loosen up & emulsify (chemically break down) any caked on sludge. So it seems to find any little hole and work it bigger and bigger until it finally leaks.

So in the case of using conventional oil and later switching to synthetic, that theory would prove true. You might have some "sludge" plugging up a hole and then when you switch, the synthetic emulsifies that sludge, opening up the hole and ofcourse causing a leak.

That's my theory at least

-Tom

 

i drove my car maybe (at the most) 250 miles since october. I changed my engine oil in october. Should i change it now since its been roughly 3 months? THanks.




-Jeff

 

I would like to pass on some info that I learned while ordering some crush washers for my diff. The FD diff uses the same crush washers that the Miatas use on their oil pans.

 

I would. Leaving used motor oil in the car for long periods of time isn't good either. Then again, I don't understand how you can drive the car that little (unless you were getting an engine change....)!

 

actually...my car has 110k original miles. I havnt driven it alot lately because i want my engine to last till i go to bootcamp. Afterwards, I will have plenty of money for rebuild and such I guess I will start changing my oil every couple months now. THanks for the advice.



-Jeff

 

Man, why Boot Camp? My dad was a career NCO in the air force and said he'd never let me enlist.....I listened and am now a Captain. I'm glad I trusted him--the life of a private really sucks, man.....

 

Just changed mine less than 2 weeks ago with Royal Purple max gear and holy **** did I notice a good amount of improvement.

Took me a few hours because I was also trying to change the tranny fluid (MT-90) at the same time and when I do such work on my car, I take all the time I want and make sure that everything is done perfectly, unlike some of the people at random shops........

-Dan

 

I think it depends on what you're going for. If you're just going for a quick 20, enlisted is perfectly fine.

I'm just in it for the retirement and to get my college all done up. No way in heck I was going to put myself through ROTC or Officer training.

Not to mention, you don't have to deal with most of the political BS that you have to deal with as an officer.

Of course, you do have to deal with the BS that some bird brain officers give you.

Sure, you might get paid more, but there's alotta pluses and negatives to each choice.

How many years have you been in as a Captain?

 

Goodfella... I am going to Army bootcamp because i enlisted in the Louisiana National Guard. I can use the free college tution, gi bill, kicker, etc. Anyway, I am considering doing ROTC through college and hopefully be accepted into the JAG program. WHich service are you in? My MOS is 13B (coincidence?) Artillery Crewman. Later.


-Jeff

 

Yeah! Join the Revolution!

Really though, just make sure you don't drip any of that $hit on your garage floor. Every warm day next summer you'll be smelling it a mile away.

 

EviLPeNeviL, you said you put Royal Purple Max Gear in and then also did the tranny. You didn't really say so I'm assuming you first did your rear end??? Can you tell us about HOW and WHAT the difference was?

Thanks,
Tom

 

quick question. how much fluid do you put in

 

wow, back from the dead in a big way

 

1.4 qt SAE 90; API GL-4 or GL-5 Ref: FSM A-18

 

 

lol thats a funny picture.




is there any online guide for rx7 maintainence (oil change, spark plug change, bumper removal instructions, etc)? it would be cool to know there is one layin around. thanx.

 

http://www.fd3s.net/
http://www.clubrx.org/default.asp
http://www.autosportracetech.com/RX-7/rx7stuff.htm
http://www.maxcooper.com/rx7/
http://www.davidgeesaman.com/ (awesome vac diagram here)

More info than you can shake a stick at!

Awesome pic Kevin!

 

neo synthetic..