Thread: Transmission Problem

Need some input on diagnosing a transmission noise...I know you can't hear it but I'll try to explain, lol. I have a 93 NX2000 that I recently swapped from an automatic to a 95 B14 manual that had 133,000 miles on it. All was well for about 1500 miles and now whenever the car is accelerating in 3rd gear it makes a noise somewhat like a jet getting ready to head down the runway. It's not terribly loud but is quite noticeable. All gears shift well and there is no grinding. No noise coming from other gears.

I am using Royal Purple gear oil...I know, should have used Redline MT90, but I read several reviews on here where people were using it with no problems. The car is bone stock except for an Ebay cone filter, so I'm guessing the 120 WHP is not the issue. I used an OEM type Exedy clutch kit and "new" axles from Advanced. The other swap stuff was collected from several sources.

The shifter linkage has some play in it, but isn't ridiculously loose. I tried adjusting it somewhat but couldn't see where it would be an issue. The tranny seems to be going into all gears well.

So...what do you think:

1. Definitely fuxored, 3rd gear components damaged.
2. Maybe swapping to Redline will quiet it some.
3. Linkage issues need to be addressed.
4. Something else...or need more info.

Any input would be appreciated.

Need to change my signature... "Swapped from Auto to Jet Simulator"

Wow, mine is making a similar noise in 1st gear, just started.

Sorry to hear that. Feedback is a little slim right now, but maybe a Good Samaritan will step in here shortly and point us toward the light.

Each individual gear spins freely on its shaft until the synchro grabs it as the linkage is moved. There is a bearing inside the gear. Since it is only noisy in 3rd gear, the noise could be from that bearing going bad. A badly worn gear or one with chipped teeth could also make that noise. You could try a heavier weight oil. I don't know what the Royal Purple viscosity rating is.
This problem can only get worse with time.

It definitely sounds like a bearing on it's last leg, but I couldn't see how it could be a bad bearing for only one gear. Thanks for the explanation. As for the viscosity, I don't remember the rating of the gear oil, but it's whatever is called for in the owner's manual. I'll try running a heavier oil and see what happens. Maybe I can get a few more months out of it before it becomes unusable. Thanks again.

I'd also go with bearing for the gear, if it's smooth doing the 4-3 shift w/o nasty grinding noises or feeling less than smooth engagement. Not proud of it, but fried my U13's trans shaft bearings esp 3rd gear, didn't do the fluid changes often enough - 50k miles, by 90k it was having issues. Under hard use I really needed to do no longer than 30k changes, cheap insurance for a time consuming and expensive repair - back when I first fried it, you couldn't just walk into a yard an pull as use trans - they weren't around, and only 15% of the U13's sold were 5 speed in USDM. Not like our B-cars, where you can pick up a decent used trans for few hundred or maybe 300 bucks, bolt it up and go.

Good luck with it!