I recently swapped out my dx transmission for a cx one with a taller final drive. The original transmission was beginning to have some issues so I decided to just replace rather than do a rebuild. Anyway I just got this new/ used tranny into the car only to find that it might be defective. First gear has a pretty bad grinding/whirring noise above 20 mph which promptly goes away when I shift into second. The rest of gears seem fine except it does grind slightly if shifted quickly into 3rd.
Here is the weird the weird thing about it all. I thought at first that the ISB might be bad, so i listened carfully while the car is idling in neutral but I could not heard the characteristic grinding noise. It only happens when the car is in gear. The other weird thing is the noise does not always occur, in fact the first few times i drove the car around the block it made no bad noises at all. Pretty odd, I understand bearing failure to be something that gets worse and worse and worse etc etc. Any Ideas?

 

Either way there is more than likely an internal issue. When you get it open you will see what is the cause whether it be a bad ISB or one that is walking. Check all your bearings and gear surfaces closely. What was the condition of the clutch?

 

The clutch is practically new with about 4k miles on it. Would dirty or incorrect transmission oil be the culprit? I'm using 10W-30 right now as per the hanes manual.

 

Regular 10w30 works fine. If its strictly a daily I would go with the recommended Honda MTF if its easily available to you. Its more than likely an internal issue.

 

Here is one for you: I had to drive the car to run an errand which required a 30 min journey on the Highway today. After the highway ride, running at about 70 mph, the gearbox hardly make a sound. WTF?

 

When you have a defective input shaft bearing the noise can be load related and since you were in 5th gear, you were loading a gear that is furthest from the input shaft.

 

i replaced my zc tranny with a 98 ex tranny due to bad syncros they tolled me it wouldnt fit but its running fine so far
wondering if ill break down on me in the near future?? need info please

 

How do you know your syncros were bad?

My #1 rule with D series, if you blame the synchros you are clueless.

Only time I've seen the brass wear out, the tranny had 400,000 miles on it.

 

I've seen a few. Not many and they tended to be very abused trannys. One had a CSB that walked and I think the guy kept holding 2nd in and drove it that way for a good 70,000kms or so. Generally speaking though I tend to find CSBs that walked and chewed up sleeves and gears.

 

thats what the so called mechanic tolled me i keep think its a bad bearing but no one agrees with me