Hi,

can anyone tell me what type of gear oil I should use to refil my manual trans?
I have an 89 Civic, i was recomended 10w30 but as I drained the old stuff out i couldn't help but notice that distinct stank of gear oil... So now I am suspicious...
Thanks

 

10w-30 or manual transmission fluid from Honda. Or GM synchromesh

 

Thanks, there is so much debate over it I see from reading threads. I guess I'll go with a 10w-30.

 

Just get genuine honda MTF from any of your local dealers. Costs about $7 a quart and it has all the proper additives a honda tranny needs.

(honda MTF is basically 10w-30, but with a CRAP load of additives.)

 

It's actually quite the opposite. Motor oil contains a crap load of additives that are completely unnecessary for a transmission. MTF has additives specifically designed to help synchros do their work while not turning into a foamy mess from the whipping action of the gears.

 

are there other suitable options than going to the stealership? 75w90 is about the lightest gear oil I've come across on the shelf.

I'm in no rush, my first hurdle to get over is the rounded over fill plug. looks like someone used a 12pt combination wrench on it a size too large. Or standard instead of metric. I jacked the car up and managed to get a socket on there but not enough meat left to turn the plug. I'm not sure where to go from here other than sacraficing and welding a wrench to the drain plug to break it loose. Whoever tightened it tightened it so hard the aluminum lip on the tranny is cracked.

Looks as if I made the dumbshit mistake draining the oil before it could be refilled. Though i thought I removed the drain and fill plugs turns out what i thought was a fill plug isn't.

 

Go with 10W-30, that's what the manual says should be used.

On crxcommunity we have a guy that builds and re-builds trannys for a living and he discourages from using Honda MTF strongly.
This is what he had to say in a thread with the exact same question as you had:

I had a call tonight, a person wanting TWO SCCA ITA trannys gone through that King Motorsports had built two years ago. Both are now making noise, crunchy shifts, etc.

Both cars are using third generation Honda MTF, aka pisswater. One tranny is out, other car not yet up in the air. I told him to drain the fluid, dump in 2 quarts of 10w30 and report back. I fear ISB is already damaged as one pops out of first gear when driven thru paddock.

Torco Fluids will be tested at end of July, beginning of August at Mid Ohio. Besides the Moser clan in their ITA CRX's I hope to one day have all the Ohio Honda ITA entries at IT Fest running trannys I've built/serviced.


Regarding the smell: If motor oil gets really old, it starts to smell kinda like gear oil. I had the same thing on my CRX when I changed the tranny oil. That oil was in there for probably 15 years

 

75w90 "gear" oil is the same thing as 10w40 motor oil. Nothing new or special. Honda MTF is a 75w80 gear oil (10w30 equivalent). Thinner for better fuel economy.

 

Thanks fellas

 

ive been wondering the same thank you

 

Go to honda and get it. thats your best bet.

 

The newer transmissions use Honda MTF, the older ones use 10w30 oil. I would recommend castrol gtx. No reason to use more expensive or different fluid.

 

I put honda MTF in mine.

then I was told it's too thin for our older transmissions because honda keeps changing the formula.

so i flushed/filled with 5w-30 eneos synthetic

then i was told synthetic is too harsh on the syncros .

so i flushed/filled with conventional 5w-30 and that's working well with a 25% concentration of lucas stabilizer.

 

royal purple syncro mesh. expensive but worth it. my buddies tranny grinded goin in third. changed from motor oil to rp syncro mesh, a week later, no grind. it works. i will never put motor oil in a tranny again.

 

personally i always u a quality full synthetic 10w-30 motor oil in my cars but what ever u do stay away from gear oil it will cause ur syncros to burn up really quickly

 

just use the 10w30.. best bet..

 

Pennzoil Syncromesh. Don't fall for the expensive "friction modified" GM blend, it made no difference in my GSR.

 

^No difference in what? The GM FM stuff helps if your having notchy or crunchy shifts. That is no joke. I've used it twice where the Honda stuff wasn't smooth enough.

 

I use recycled 10-30W in my trannsmission. It's at 180K right now. My car pumps out a whopping 52 hp to the wheels, so I don't see any reason to be worried about the "high-perf" gear oil.

 

what kind of car did you use it in? I'm rockin the honda mtf in my 90 si and it still shifts a little rough

 

1st time was an 03 Element AWD 5MT. The clutch slave took a dump and the resulting limping to dealer ate up 3rd. After replacing the synchro, the gear was ALWAYS notchy. My wife complained of it popping out of gear or not going in at all at least once each time she drove it (dealer said it's normal.....NOT!). I switched to GMSMFM and never had a single bad shift again.

05 Acura TL 6MT with typical 3rd gear problem. I had tried the then reformulated Acura/Honda MTF (white cap) and it worked great for exactly 1000 miles. Then it started acting up again like before. Dealer checked it and replaced the 3rd gear synchro under warranty. It was fine for a few years. Finally in the freezing cold of Reno, I had a single notchy shift and I immediately switched to the GMSMFM. It's been perfect ever since (over a year).

If shifts are rough, give it a shot. You have nothing to loose.