When I drained the manual transmission for my 1991 Civic DX (D15B2 engine) I noticed a fog of fine metal particles in the oil. The lubricant was changed only 15K miles earlier when I installed Honda Manual Transmission fluid because the dealer told me it was superior to the 10W-30 motor oil the shop manual recommends. This car has > 230K miles but it has been well maintained and driven moderately. I am rebuilding the engine in the hope of driving this car for 200K more miles. I have several questions
1) What specific steps should I take to lengthen the life of the transmission?
2) Are fine metal particles normally found in transmission oil after only 15 miles of moderate driving?
3) Should I change to a different lubricant, e.g. synthetic transmission oil. Please recommend which lubricant
4) Do you know where I can purchase a magnetic drain plug for this engine that will keep these metal particles out suspension?

 

Changing the transmission oil according to the manual's specifications and making sure it is properly filled is the best thing you can do to prolong life.

The fine metal particles are a result of synchro and gear wear, and is ok as long as it is not accompanied by large metal pieces or if the oil appears more silver than golden brown.

I definitely think honda MTF is the stuff you should be using.

It is important to note that honda MTF contains a moderate quantity of zinc, which helps the sychros bite, which should be in suspension with the oil, and may be partially responsible for how strange the oil looks.

I think Password:JDM has magnetic trans plugs for sale, and i think King Motorsports also has them. The Transmission also contains a magnet already, which might need to be cleaned off after 200k miles. you can safely clean off the magnet without having any prior transmission work under your belt. you just have to crack the case and pull out the magnet, then put the case back together.

Manual transmissions, even under normal operating circumstances, will wear out at some point. The way the transmission functions involves very slow destructive modification of the gear cones, syhchros and shift collars and fork. Properly lubricated, i would guess a honda transmission could go probably 300k-400k before parts are out of spec according to the manual, barring seal and bearing failure.
usually your input shaft bearing will start to go before the parts mentioned above get too worn out, however.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DennisWaller &raquo;</TD></TR><TR><TD CLASS="quote">
2) Are fine metal particles normally found in transmission oil after only 15 miles of moderate driving?</TD></TR></TABLE>

definitely NOT!

honda MTF is definately better than straight motor oil. and i wouldnt use synthetic either. its not needed.

there is already a magnet inside the tranny to collect any particle.

but ive never seen any significant metal come out of a GOOD tranny. only the bad ones...

i dont think theres much else you can do once the wear and damage is already done if thats the case.

 

whoa.. yeah.. 15 miles or 15k? At the top I read 15k miles, but then he said 15 miles for #2

15 miles there should be none.. but 15k your are probably ok.

 

Like the others have already said use the Honda MTF however I had used motor oil for years in my tranny with no ill effects I think some metal particules will be normal but now you posted 2 different mileage one said 15K miles the other said 15 miles if it was only after 15 miles there MIGHT be something wrong or its just flushing out more particules that were already there.

Either way use the Honda MTF and drive normally and you should be fine, it the trannies (especially 5 spd DX's) arent too expensive so I would buy another used one rather than getting it rebuilt will be cheaper and just for daily driving it will be fine. This is of course IF the tranny does go out.

 

just changed my oil today and there was no metal what so ever and I haven't changed it in probably about 35,000 Kilometers. Its a Y1 by the way with no grinds on 3rd and it only has 143,984 kilometers on it. And last time all i used was castrol 10w30

 

The transmission is quiet and shifts smoothly with no indications of abnormal wear such as noise, slipping out of gear or balky shifts. However, since I have removed the transmission and the engine as a unit and both have been driven &gt; $230K miles now is the optimal time to substitute another transmission with less mileage. I have several questions:
1) If I separate the transmission case what evidence should I look for to determine whether my transmission is worn and approaching the end of its life? I noted the statement that these transmissions are only designed to be used for 300-400K miles and I want it to last for longer than that.
2) Several local Honda owners have suggested that I purchase a used transmission imported from Japan. Is this a good idea?
3) several companies in the Seattle area sell such transmissions and they all claim the used transmissions from Japan will have only 60K miles on it when they are removed. I know of no way to verify the accuracy of that claim. Is there evidence to support its veracity?
Your comments and suggestions will be appreciated.
Dennis Waller

 

like i said, theres a magnet in the casing, you can look at that for evidence of metal shavings.

worn synchros are a good indication too. and check each bearing for smoothness.

ive bought several japanese transmissions. every one of them was in pristine condition. i would recommend it also.

no way to verify the age, but the emissions laws in japan sort of force cars to be retired early as they start to raise the registration tax, or something like that, once a car hits 60k or whatever.

i recently took my engine and tranny out as a unit to replace the engine and reused my tranny with 245k miles. for whatever reason, 2 months later and just last weekend, i had to take the tranny out and replace a very, very bad differential bearing (i thought it was the input shaft bearing, it wasnt). i cant say i should have known to check the tranny while it was out already, but i of course wish i had.

 

I have decided to rebuild my current Civic transmission as a preventive maintenance task: the transmission is quiet, shifts smoothly and does not have any other signs of wear such as balky shifts or slipping out of gear despite the 230K miles. When I opened the case I found both the synchros and the gears in good condition with only a small amount of metal particles attached to the magnet. In addition to replacing all of the seals Sanimalp suggested the input shaft bearing was usually the first to fail. What other bearings are prone to failure? I would prefer to replace those parts now rather than having to remove the transmission again in 50K miles.
Dennis Waller

 

my diff bearing finally failed at 245k miles... but its not typical.

thought it was my mainshaft (input) bearing, but it wasnt. i still replaced it and the seal tho.

i realize im just repeating myself. heh. i say just go with what you got.

 

I agree that the diff bearings should be changed. the input shaft and diff bearings are the 3 most likely to fail. The rest I haven't seen fail yet.

While you are in there, though you may just look at changing all the bearings, that way you don't have to worry about it. The rest of the bearings only cost around $20-$40 a piece.