fluid questions

I need to change ALL the fluids on the wagon. I had lost the spreadsheet that had the maintenance schedule on it, so now I need to start over

While searching, I found the following:

Transmission fluid:

Coastal DEX III $4 a quart
Max life DEX III $5 a quart
Coastal DEX VI $5.5 a quart

Gear Oil (75W90):

Coastal $3.49 a Quart
Mobie 1 $8.99
Royal Purple $16 but this stuff has the posi additive already in it.


Conventional and synthetic is available on both

While I understand that the owners manual recommends certain fluids, it was printed 13 years ago and technology has improved GREATLY since then. bobistheiolguy was of little help. Any advice on what to get?

Anybody??


This is frustrating!!!!

Chiltons, Haynes, and the owners manual all say WHAT to use, just not how much:x

I found in the Haynes that it requires 4oz of friction modifier. Will 8oz hurt, make a difference, or just do nothing but cost me more?

Only one bottle of the posi additive is needed. Be sure and use the GM brand cause all others I have ever used made the rear clatter like hell.

I use synthetic gear lube and regular trans fluid in my cars. I still run conventional engine oil cause I myself do not care for the lower pressure of synthetic.

Krzdimond wrote:

While I understand that the owners manual recommends certain fluids, it was printed 13 years ago and technology has improved GREATLY since then. bobistheiolguy was of little help. Any advice on what to get?

Robert:

Oil formulation and properties are for the most part a black art. Everyone wants their formulation to be a propriatary mix but since our manuals have been printed, the EPA (and other environmental agencies) have collectively stuck their magic wands into the boiling caldron.

Our cars were the first attempt for the enviro community to dictate what we can and cannot use in our engines. If they had gotten their way, we would only be able to buy 30 wieght motor oil with no zinc or other heavy metals. While our manuals state 10w 30, depending on the age of your engine, and the condition of oil control rings, seals, bearings etc. you may want to try a heavier oil. I have used 10w 40 in all my gassers and 15w 40 in the diesels and continue to do so. Also add a can of Moly (if you can find it). If you can't find Moly then use a bottle of the red STP. The blue doesn't have as much zinc.

The new standards are really effecting what we can buy up here and 10w 40 is getting real hard to find. If my engine is over 150,000 miles old, then I will use 20w 50 during the summer. Any reputable name brand (don't take a chance with generic or house brands unless you can trace their point of origin) are pretty close to each other. I prefer Quacker State for my gassers and Shell Rotella for the diesels.

The biggest advances during the last decade has been in synthetics. The first thing to consider is the feedstock. True synthetic is a molecular reconstruction of hydro carbons to produce a truly consistant base from which to work with. Unfortunately, our truth in advertising has allowed some companies to label their product as synthetic when in actual fact all they have done is run standard feedstock through a few catalysts to purefy it and the end result dosn't always have the same characteristics as the true synthetics, like temperature stability, dispersant qualities etc. To my knowledge the only true synthetics are Mobil 1, Amsoil and I suspect Royal Purple. May of changed over the past few years but non the less, check first.

Re-vist bobistheoilguy.com and do some reading (join the forum and follow some of the threads..it's a real eye opener). Everyone has their favourite lubricant and additive but the reality is modern oils are all pretty good and the ad packs used are fairly universal, except where the EPA has dictated the exclusion of some proven additives because it will foul up the new cats or spew miniscule amounts of heavy metals out of the tailpipe from a clapped out, oil burning piston pounder that should have been retired long ago. The rule of thumb for oil pressure is 10lbs/1,000RPMs. Its not the pressure that does the work, it's the volume of oil.

Hope this helps.

Bill

94Woody wrote:

I use synthetic gear lube and regular trans fluid in my cars. I still run conventional engine oil cause I myself do not care for the lower pressure of synthetic.

I have been using Mobile 1 in many of my cars since the mid 90's. I found that I had a slight increase in pressure and it was more consistent as the engine warmed up, it maintained it's color longer, and I still have 30 p.s.i. at idle and 60 p.s.i. reading on my gauge at above idle even with a nasty knock, go figure. While I cannot vouch for the treatment of my car or it's maintenance schedule prior to 2005 and the 139k miles that were put on it before I bought it, it did spin a bearing at 178k but I am not going to blame the oil.

Differential capacity: 2 1/7 Quarts With 8 1/2" ring gear (Located bottom center of ID tag) 1 3/4 Quarts With 7 1/2" ring gear
Transmission capacity: 5 Quarts Fluid and filter change 11.4 Quarts Total refill (includes torque converter)
Engine capacity: 5 Quarts Including filter
All this info was found on [You must be registered and logged in to see this link.] under specifications. They also offer an online service history that will provide you email reminders of when service is due.

I've put Royal Purple gear oil in my 93's rear end and it's quiet and seems to have less resistance than it did with the GM stuff in there. I also use the Royla purple in the engine, haven't gotten around to swap the fluid out of the tranny yet but whe I do that one it too will get royal purple tranny fluid.

Just my two cents
(after buying royal purple that's all I got left!)

Correct me if I'm wrong, but I believe the posi additive actually makes the clutches slip more to get rid of the chatter when you turn a corner. The chatter is caused by the clutches grabbing. So I'm thinking that if you put more friction modifier in the rear end you may effect how well the posi works.

So I would suggest you add the exact amount GM recommends.

Correct. One bottle is all that is needed.