Synthetic conversion this weekend.

[Hemi 'Kota]

Hi all,

I am planning on converting all the fluids (engine, trans, rear) to synthetic (royal purple) this weekend, and have a couple quick questions. The rear end takes 75w-90...what does the 5spd manual trans use, the same or ATF? How many quarts for the rear end? How many for the transmission?

Thanks,

------------------
"...they don't make no seatbelt for the mind, so I can't buckle up for this ride..."
Jason (aka Mr Belvedere; aka Ford Fairlane)
2000 Dodge Dakota Sport. 4.7L V8, 5-spd, and 3.55gears.
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[This message has been edited by Hemi 'Kota (edited September 13, 2000).]

[Deep Dak]

Just changed my 5-speed trans fluid to Valvoline Synthetic 75w-90 gear oil API GL-5. It took between 3-3.5 quarts. Hope this help and enjoy the smell.

[Hemi 'Kota]

Thanks much DeepDak. I don't have to worry about the smell...my sniffer isn't very effective ! Have you had it long enough to notice if there are any mileage improvements? Does it shift any different?

Jason

[Deep Dak]

I'm on my first tank after the change, so no info yet. I also put in a Hurst shifter, so it shifts MUCH better. I didn't give the stock shifter a go with the new fluid. The rear differential fluid will be changed to synthetic in about two weeks. Waiting on some new gears. October '00 of High Performance Mopar changed all the fluid of a 5.2L Dakota to synthetic. They put it on the dyno and hp increased by 9.2 with torque by 3.0 (at the wheels)! It's worth the price of synthetic to me!

[GS -]

Warning!The manual transmission NV-3500 requires a synthetic fluid with no sulfur content in it. The sulfur will cause corrosion of the synchros. The only synthetic fluid that I know of that meets this discription is Redline MTL, which states on the bottle itself that it has none. If your shifting starts getting chunky you'll know whats going on. BTW, I've only been able to get 2 qts (64 ozs) in this tranny before it comes out the filler hole in my '98. Advise checking the owners manual.

GS -



[This message has been edited by GS - (edited September 16, 2000).]

[Hemi 'Kota]

My owner's manual doesn't have capacities for the differential or tranny, nor does it give the recommended lube for the tranny...that is why I posted (that and I'm sick and tired of dealing with dealerships in general). Thanks for the warning on sulfer content, I will call up RP in the morning and ask them about it.

Thanks GS,
Jason

[GS -]

HK, I've used Royal Purple race 21 and 41. Its good oil. The oil is a polymer and does not break down like Mobil1 (hydrocarbon)RP simply gets dirty. BTW, Mobil1 is a great synthetic oil and I use it as well. When money is short I simply mix the two.

[Deep Dak]

Sorry, forgot to mention I have the AX-15 manual transmission. The AX-15 requires 6.6 pts (3.3 or so quarts), while the NV1500 & NV3500 only requires 4.2 pts (2 quarts). Thats right, I'm the proud owner of a V6! Now don't you all start getting jealous at once. Oh, 8.25 inch rear axle requires 4.4 pts (2.2 quarts). 9.25 inch rear axle requires 4.8 pts (2.4 quarts) On the Valvoline Synthetic 75w-90 it mentioned that it is not recommended for limited slip differentials. Is this due to the sulfur content?

[GS -]

DD, the synchros in the manual tranny are made of softer metals than in the rearend so more prone to corrosion. I would assume that Valvoline does not have an adequate LSD additive in its syn 75w-90 to qualify it for a limited slip lubricant. There are some pretty good syn LSD lubricants out there. Redline and Amsoil just to name a few.

[Deep Dak]

GS:
I haven't read anywhere if the AX-15 can or can't have gear oil with sulfur content. Do you have any info on this? Neither the owner's manual or the Haynes repair manual say anything about this. Thanks

[GS -]

I think it uses a GL-5 equivalent lubricant, which has some sulfer in it. My '97 Dakota was a V6 with AX-15 tranny and I remember trying Mobil1 syn 75w90 in it. The shifting was really chunky and on cold mornings it would barely go into 2nd. The AX-15 is also a Japanese transmission and not made by New Venture....uuugh! its 4:00am I'm gonna get some sleep...If you can find some Redline MTL or if RP makes a M.tranny fluid use it, both are excellant brands. Any other syn besides Amsoil, Redline and RP may need a
LSD additive to keep it shifting smooth. By all means do some research to verify this info because the AX-15 may have changed since '97.

[Mr Belvedere]

Hey GS,

Is that the difference between a GL-5 and GL-6 rating, that the GL-6 doesn't have sulfer and the GL-5 does?

Thanks for the info,
Jason

[Deep Dak]

I know the GL-5 usually contains sulur, anyone know if the GL-3 contains sulfur? The AX-15 uses 75w-90 API GL-3 or equivalent. When I go to some of the auto parts store, all the different gear oils seem to be GL-5 or higher.

[GS -]

Hey guys try this web site. I think you'll find it interesting. Don't forget to check out the TOP of this page.
http://www.vtr.org/maintain/lubrican....html#gear-oil

[This message has been edited by GS - (edited September 17, 2000).]

[Hemi 'Kota]

Great link GS,

So, what do you think of running a gear oil with a friction modifier in an open rear? Could it do any harm? Could there be any gains due to the "make the base oil much more slippery" effect?

Jason

[GS -]

HK, If I remember correctly, it was Mopar Muscle that reported gains in 1/4 mile times by just switching over to a synthetic. But to answer your question, I think an additve (friction modifier)surely could not hurt an open differential and at the most it would just be overkill. With gas prices the way they are a good synthetic will save a little more money at the pumps. I do 80 miles rt per day, have a '98 318 w/5 speed and get close to 20mpg with 3.90 gears, 19 with A/C. It all adds up if you want to make something more efficient.



[This message has been edited by GS - (edited September 17, 2000).]