My 91 SE 5spd is in really good shape for its age, but I am concerned about some noises coming from the transmission under harder acceleration. It is a chattering like gears spinning together really fast, but seems more pronounced than just normal transmission noise. I can only hear it at freeway speeds in 4th and 5th, and really only when I am pushing the car to accelerate quickly. Does this sound like notmal transmission wear as it gets older, or am I looking at something more serious?

Thanks!

 

I suspect something serious like a bad bearing. Perhaps others here will be able to more full diagnose your problem.

 

Input shaft bearing...Maybe?

 

bearings wouldn't cause chattering, and bearings noises should be noticeable whenever the bearing is in use. a bad input shaft bearing will make noise until you release the clutch. have you checked axles?

 

Do you mean when the clutch is let out?

If that is what you mean then you are wrong...The input shaft bearing will make noise though out the gear range as you accelarate and sitting in neutral with the clutch let out....

 

release the clutch as in depress the pedal.

as in release the clutch from flywheel.

 

So, to clarify, its only when its in 3,4,5 gears (higher speeds as well) and it is a chatter, like I can hear the gears more clearly than before. It is a chatter, like winding up those toy teeth that click, but much faster. My foot is not on the clutch pedal when it happens, If i push the clutch in, obviously the noise stops.

 

Ok...I see...Tomato...Tomato...

 

Where is the input shaft bearing. this is not the Throw out bearing in the clutch, is it?

 

no, the throw out bearing is seperate from the input shaft bearing. input bearing is inside tranny case. as you say though, as you push the clutch pedal in the noise stops. this means that the chatter is internals, since the noise is only noticeable when the gears are engaged. since only 3,4,5 gears are effected, that leads me to believe you may need some expert advice on 5spd internals.

 

If that is the case does this mean the transmission is on the way out?

 

Let me know before you throw it away; my friend can do rebuilds very cheap.

 

how cheap, more importantly how fast.

 

When you put it in 4th, does the stick shake in your hand a bit?

 

No, not really. Its just this noise. I took the plastic surround off so I could really hear the tranny and i found out in all gears, when I am accellerating hard there is just an amplified sound of gears meshing. I am not sure how long it has been happening, but I figured I would ask incase its not regular. DOes anyone here have gear noise when they are accelerating hard?

 

Maybe they arent getting a good coating of lube, have you checked the level or changed the oil lately?

~Alex

 

Is there a writeup on here for changing the MT fluid yourself? Does anyone see a problem with switching to redline MT fluid?

 

i have redline in my tranny and i can't speak highly enough about it. with 189k like mine, transaxles are supposed to have at least some noise emmitted. i haven't heard a peep from my trans since i pulled it out and filled with redline. if you decide to switch, it isn't that difficult.
start off by lifting the vehicle in the air wtih ramps, jacks, or a lift. next find the drain plug on the passenger's side of the trans directly in front of where the linkage rod meets the trans. now drain. make sure you check the fluid that is released, check for metal shavings and anything other than used gear oil. shavings may be too small to see with naked eye, causing the entire fluid to look as though it has a sheen or metallic. if everything looks good, replace the plug when COMPLETELY drained. if you find the filler plug early you may want to purge old fluid out by pouring new gear oil in after draining, with the drain plug out. once you have finished draining, the filler plug is on the driver's side of the trans on the front, halfway up the case. this is a difficult filler hole to get to, so i filled a spray bottle with a screw on 45 deg elbow to reach. fill with the correct amount of fluid, replace the plug and you're set.
i'm sure i may have left out a step or two, so anybody feel free to chime in. if you still have your under engine cover, the left side will need to be removed first thing as well. shoot any more q's you may have.

matt

 

That is a great writeup, thanks for the help. Only question that remains is what is trhe correct amount of fluid fot the '91 MT, and are there any special tools (other than a metric wrench set) needed to get it done?

 

i believe you need around 4 1/2 quarts, but i need to check my fsm to be sure. you only need your basic metric sockets and ratchet. i checked the fsm and it says 10 pints, whatever that works out to. i filled up the trans until the level was near even with the filler plug.

 

Based on Info; your Input Shaft Bearing is shot. If you open tranny; sugest you replace all bearings. This is typical when Oil is not replaced periodically ( Happened to Me). You can get a Tranny kit from www.drivetrain.com in Las Vegas for about $400+. Did the job myself but I suggest using a PRO. It requires a special tool to pull the Diferential bearings out and Most always the Plastic Spedometer gear (behind left defferential bearing) gets broken when pulling bearing out; so i recomend you purchase one.