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I have a couple of things that I am going to need help with in the next days so I will be posting a couple of threads tonight.
First is the Differential Fluid drain and change. I plan to do this tomorrow if possible. I know this can get really controversial but I really REALLY want to keep it sweet and simple - if possible.
I have a 1986 Manual 5 Speed. I dont know anything about telling if it is a LSD car. Actually,,, that is one of the MAIN reasons for the post. How do I tell? Does the year tell all?
~ I have loosened all three plugs - ready to go.
~ THE CRAZY Question ---- which fluid?
~ I have a little hand pump for refilling.
~ I am interested in but do not demand additives. I will of course add LSD additive if I even have a LSD set up.
~ Does the angle of the car when refilling matter?
I am willing to just get and use a BASIC Differential Gear Box Fluid. Yup, Sweet and simple.
Jack it on the crossmember. Turn one of the wheels, if the other one rotates in the same direction you have LSD..
If I do in fact have LED is there anything special I need to do,,, or should do,,, with new fluids? I do like to keep it pretty straight forward believing that she should work pretty well with the fluids she was designed using. I want to get her as OEM" as possible before adding stuff.
Sorry I don't know but you can bet your bottom dollar someone here will. You should find fuilds listed in the owners manual under filling capacities.
In the meantime search is your friend...
Understood and I hear you. On this subject and a few others sometimes searching can give as many questions as answers. There are a lot and various opinions on this. I'm hoping for the skinny, lol!
Unfortunately with oil threads you really just have to do your own homework and make a choice. There is no end to lubrication recommendations and most posts are purely anecdotal - or based on limited research at best. What you'll find is that the majority of guys are running Mobil 1 75W90LS or some form of Redline. I THINK Greg Brown recommends Mobil 1 as his experience is that he sees more seal leaks when using Redline. Please search to confirm this. It's just my recollection. YMMV.
There is an issue on Mobil 1 I've always had some concern with, which is that Mobil claims for it to be a "gear oil" but makes no reference to use in transmissions or reference to being safe for synchros. So take that for what it's worth. Plenty of guys have used it for years with no issues, so I will assume its properties are adequate.
I have an LSD trans in my '84. The early 928s use a clutch type LSD. (I'm not sure how the later PSD systems work - I've never researched them). The Mobil 1 gear oil is safe for LSDs and works fine as is with no additive. That is what I'm using now. If you go with Redline you will want to use Redline 75W90NS with the caveat that if you have an LSD you'll want to blend about 25% Redline 75W90.
Redline is a bit finicky when you have a transaxle that also has LSD. The LSD likes the slippery properties of the 75W90 but if you run pure 75W90 it can increase synchro wear. From Redlines website:
This product is not designed for use in most manual transmissions or transaxles in passenger vehicles, since the extreme slipperiness may cause synchronizer mesh issues that lead to shifting problems.
At the same time, if you do have an LSD and you run pure 75W90NS you may get some "chatter" from the LSD clutch plates when going around corners. I know my car made some chatter when I tried running pure Redline 75W90NS. The solution was to use about 1 QT of 75W90 and the balance was 75W90NS, which took away the chatter but was still protective of the synchros.
On my next transaxle oil change I decided to go with Mobil 1 75W90 LS. For my own personal anecdote, I historically used Redline but was experiencing some minor leaks at seals which had only recently been replaced. I switched to Mobil 1 based on some recommendations that it was less prone to leaking. My experience has been that the car is a bit harder to shift using the Mobil 1 and I'll probably switch back to the Redline mixture on my next fluid change. Again, your experiences may differ but ultimately it will come down to what works best in YOUR car. And it may require a little trial and error.
Oil: M1 Gear Oil is a GL-5 oil. Spec books call for a GL-5 gear oil.
Car needs to be level when filling to get the proper level: oil just starting to run out of the fill port.
Always, loosen the fill plug before draining oil.
Always use new crush rings on the plugs.
Always use a torque wrench to tighten the plugs. The spec is 22 nm for '87+. This torque will be easily exceeded when you use any tool you have that fits the Alan socket in the plug, because it will be a big tool.
That above sentence is why you always remove the fill plug first, lest you discover, after you drained the oil, that the person that last drained your oil didn't use a torque wrench and the fill plug is seized.
Last, if you find a ~1/2 x 1.5 x thin hunk of metal on one of the magnetic drain plugs, don't have a cow.
At the risk of offending the devout, the book specifies GL-5. Most major manufacturers have a gear oil that meets that spec. Most are synthetic, but not all.
Use what you like best.
Mobil is a good one. I use Amsoil myself (The "Severe Gear" is GL-5).
You noted that you had all three plugs out. Depending on how bad the old stuff looked, you might want to lower one end of the car and let it drain for a while (overnight or even longer).
Yes, I know that each additional hour will net you maybe an ounce (maybe), but it won't hurt.
As was noted, the torque spec is ridiculously low. Do not overtighten the plugs.
The 'thin hunk of metal' is the lockout spring for reverse. The list of 'had a cow when they found it on the magnet' club members is pretty long. I found mine about 6 years ago, no issues with the transmission.
You all are amazing. Thank you so much for all th input and guidance...
So,,, I got her done (but maybe shouldn't have). I jacked her way up, undid the front plug, this beautiful (not stinky) flow of golden-ish oil flowed with a hue of some color I had never seen in an oil. Royal Purple? Let it go til it all but stopped, maybe an hour. Then, lowered her and waited for flow from the rear plug, nothing there. A good bit more than the 3.85lts came out. I think it was closer to 5!?!?!
Replaced with mobile 1 which seemed to be of a much lower viscosity than what came out. I made a stupid mistake a couple of days ago, placing "fancy TT" plugs in place of the right Bosch plugs (Roger is sending me right Bosch plugs as we speak). At that I will drive her and get a feel for the difference. So far, not right running, I get LESS of that BOUNCE one might get (it annoys me,,, especially with city driving) in low gears, low speeds, at low idles that is only resolved by pressing in clutch. From all of yalls experience,,, is a lessening of that BOUNCE something that can be solved by a different gear oil?
Did find some shavings, btw. Nothing toooo extreme.
Pumped new fluid back in,,, was not as hard as I was imaging at all. Thanks so much for the guidance...
05-01-2019, 10:17 PM
Differential/Gear Fluid Change Sweet and Simple.
