flushing 5 speed with motor oil?

[victor_t]

I will change the crappy gear oil I put in the manual transmission, but before adding the new oil, I was thinking of "cleaning" the transmission to remove all traces of the old additives.

what would happen if I replaced the gear oil with some standard motor oil and drove for a few kilometers?

does motor oil contain anything that can be harmful to the manual transmission?

[TheMAN]

so are you just afraid of mixing the new gear oil with the old one? if by that logic, then you're mixing motor oil with the old gear oil AND with the new gear oil once you drain it out and a bit is left inside

it doesn't make sense at all and it's totally pointless at even attempting to do this even if it doesn't damage the transmission... just drain the old stuff out and put the new stuff in and go!

[Cosmo77]

well for one its the wrong viscosity...

If you just let the tranny drain for a good half hour, your gonna get most of it out. Just take it for a drive before hand to get the tranny oil hot and then pull the plug and let it drain for awhile, make sure you do it while the car is level.

Use a good quality 75w-90 oil. Synthetic is better, but regular will do just fine if you change it from time to time. Mazda used to say ever 48k, but now they don't really have an interval for them. So if your using regular oil...I would say every 48-50k is good.

Cosmo

[victor_t]

I was just thinking of removing all the old additives or any modifiers the "old" oil had.

my choice of oil here locally is sort-of limited and I don't know what to choose.

canadian tire only has motomaster synthetic 75w90 GL5, which is what I put in and now I can feel the all shifts, they are not smooth at all. shifting gets better at higher temp but overall sucks. the original oil was much better.

walmart has castrol syntec, it's another 75w90 GL5

napa autoparts has either pennzoil synchromesh or a pennzoil 75w90 synthetic, not sure if it's GL5 or GL4

[Cosmo77]

The Castrol is a good oil...it should do the job quiet well. I use Castrol in all my race equipment (shamless plug)

Cosmo

[TheMAN]

the best gear oil for mazda transmissions have always been Red Line's MT90

people tried other brands and the results have been spotty at best

[Harbour Rat]

I ran Castrol Syntec 75W90 for a while before I switched to Synchromesh. The Castrol stuff was fine as far as I could tell.

If you have a Ford dealer nearby then the Motorcraft 75W90 Synthetic (http://www.fcsdchemicalsandlubricants.com/dealer/product.asp?product=Full%20Synthetic%20Manual%20Tr ansmission%20Fluid&category=Transmission%20Fluid) I mentioned in your other thread should be easy enough to get. I gather it is kind of expensive though, might be good to call first and see if the price is reasonable.

My local UAP/NAPA stocks Royal Purple oils. They charge top dollar too but for a one time purchase maybe you can justify paying what they want. If it makes your transmission work right that has to be worth something.

[TheMAN]

my friend has used royal purple in his protege (which has basically the same transmission as the 3), and the shifting has always been crunchy... when he switched to redline last week, the difference was like night and ay

[Walrus]

I was just thinking of removing all the old additives or any modifiers the "old" oil had.

my choice of oil here locally is sort-of limited and I don't know what to choose.

canadian tire only has motomaster synthetic 75w90 GL5, which is what I put in and now I can feel the all shifts, they are not smooth at all. shifting gets better at higher temp but overall sucks. the original oil was much better.

walmart has castrol syntec, it's another 75w90 GL5

napa autoparts has either pennzoil synchromesh or a pennzoil 75w90 synthetic, not sure if it's GL5 or GL4

You are still going after the wrong stuff, except maybe the pennzoil synchromesh.

Just find somewhere you can get Redline MT-90.

[OILm.ca]

Amsoil ... has correct oil for your application
Don't flush it .. suck the oil from tranny and refiill

[Harbour Rat]

napa autoparts has either pennzoil synchromesh or a pennzoil 75w90 synthetic, not sure if it's GL5 or GL4

Pennzoil Synchromesh is the same as GM Synchromesh, the stuff I'm running now. In fact, rumour has it Pennzoil-Quaker State (and Texaco) are the OEM suppliers for "real" GM Synchromesh fluid.

Pennzoil lists both GL4 and GL5 75W90 oils on their website (http://www.pennzoil.com/transmission-fluids-and-gear-oil/) so I guess you would have to check the bottle and see what it says.

[victor_t]

I would try the synchromesh except it is not a 75W90 GL4 fluid so I'm afraid about warranty issues.

[Harbour Rat]

Warranty concern is a perfectly valid reason to avoid Synchromesh. It didn't worry me too much but I understand the concern. You gotta feel right about what you put in your car so go with your gut and stick with 75W90.

If the Pennzoil stuff at your UAP/NAPA is GL4 then that will be good. If not then the Motorcraft 75W90 I linked earlier is available at any Ford dealer. The Castrol Syntec 75W90 is GL5 but it works very well and the owner's manual does specify GL4 or GL5 so there are no warranty concerns there. The only problem I see is there are too many choices.

[LovemyMazda]

I agree with TheMan. I switched to Redline MT90 in my manual Tranny at 76000 km. Great stuff if you can find it!

[Zoom Zoom Boy]

I agree with TheMan. I switched to Redline MT90 in my manual Tranny at 76000 km. Great stuff if you can find it!

CTA Patrique (CTA Motorsports) is a sponsor on here and he carries Redline MT90. Send him a PM.