leadfoot4

Not to be an "azzhat", but when asking for technical help, it makes it a hell of a lot easier, if you provide some details about your car, in your first post that asks for help/advice.

Just sayin...............

sparky77

I would not use any synthetic gear oil in a trans that is that old .They need the cushion of the older additives.Synthetic gear oil is to thin and will not slow the gears down between shifts.

leadfoot4

I disagree.


Prior to purchasing my C-5, in 2001, I owned a '77 Pontiac T/A. I bought it brand new, and kept it for 24 years. 3-4 years before I sold it, the front bearing in the transmission (Borg-Warner 4 speed manual)began to get a little "noisy". I pulled the transmission out and replaced the bearing. After re-installing it, I filled it with synthetic gear oil. The shifting, although not that bad before, immediately improved, and it ran quieter.

My $0.02 worth.

jim2527

I'll add to post #19...and this is just a jim2527 thing so with that being said....

Buy 2 rounds of fluid....change fluid as described. Drive around until new fluid is hot then change it again. A lot of old nasty fluid is still in there. Again, this is a jim2527 thing and no harm will come if you don't.

leadfoot4

I agree, 100%

~Stingray

So what is the consensus on synthetic vs not? I still use conventional oil in the engine, I would have thought it would be the same for the transmission.

~Stingray

I might just do this. I know it has been a while since it was changed. Not many miles, but time has passed.

Dodosmike

My Dad bought my Mom a brand new AMC Spirit (like a Gremlin) in 1978. My grandmas neighbor was a AMC mechanic back then. Once the warranty was off he did the service work on the car. Mom complained of hard shifts so Dad too the car to the mechanic, drained the gear oil, refilled with kerosene, ran the car on the lift for a few minutes, long enough to drink a beer, drained it and refilled with gear oil. I recall being surprised at the color of the kerosene coming out of it, grey.

I wouldn't be to concerned whether its dino or synthetic, either will be better than the 37 year old goop that's in it now. If the syn causes a drip here or there, so be it. Its undercoating, lol.

~Stingray

Kerosene...wow, never would have even considered that. Seems bad though. It it breaks down oil, then your whole gear box will have remnants of it when the new oil goes in. Wouldn't that start breaking that down early?

I guess you could do the rinse with oil as mentioned above. Still not sure I would want to try it.

Dodosmike

Unless I missed it, is the trans a 4spd standard or a 4spd automatic? If its an auto, just drain, swap the filter, and refill with the correct ATF, ford and chev are the same, and mopar is something different, according to the label on the bottle of ATF I bought last week.

Im not condoning doing the kerosene "rinse", but that is what it was. The Spirit was a 4spd manual car.

Ive used diesel fuel to "rinse" outboard motor gearboxes that have been sitting for decades untouched. Fill and let them sit. Rotate the driveshaft a few times every day or so for a week. They come right apart and get a liberal cleaning with brake clean as well prior to reassembly.

Id get yours warm(ish), drain and let it drip over night if possible. See what comes out of it, milky, clear, foamy, colour etc, and see if it should be "rinsed" somehow. Might need to fill and drain a couple times depending on what comes out of it.

~Stingray

Its a 4 spd.

Ya, I was thinking of doing a "flush" buy a gallon and run it through with the first 1.5-2 quarts. Go for a drive, 30 minutes or so. Enough to hit all the gears and slosh it around a bit.

Then come back and let it drain overnight again.

Refill and check it again at the end of the season next year.

Dodosmike

Forgive me but, 4spd:

automatic or standard?

Dont do the "kerosene flush" on an auto. That'd be bad

xpoc454

Good information here. I don't know if the gear oil in my manual has ever been changed to be honest. I will add that on the list of things to do.

I read above that you need a pump to pump the gear oil into the top fill plug. I think if anyone who has a gear oil pump to replace lower gear oil in an outboard could use it to do the pumping?

thanks
jim

Dodosmike

Outlet on a outboard motor gear case pump are usually pretty small. Make sure the gear oil is somewhat warm if your going to try it.

Jermo

I would take off your fill plug first (top plug) for the reason the plugs have been in the car for 37 years,if the fill plug(top plug) is frozen and you can't get it off and you take the drain plug off first then can't get the fill plug off, your screwed! Once you get both plugs off and have drained all the fluid, replace the the drain plug and do not over fill the transmission to the top hole, you need to only fill enough to stick your pinky finger in the hole enough to feel the fluid. So the fluid should be about an half inch below the top fill plug. Over filling the transmission will cause it to leak. I have been taught this fill trick by several transmission experts.

~Stingray

Can you take gear oil to autozone or a place like that to be discarded like normal engine oil?

gguillot

I don't see why not. Its just heavier oil. Last time I did it, I just poured it in with the regular used engine oil that I was recycling.

leadfoot4

Jermo

Yes, i do

~Stingray

So is there a worry about quality?

I found this at walmart for $13.
https://www.walmart.com/ip/Super-Tec...allon/16795067

Amazon has lucas oil for $30.