Trans noise

[Tercbeater]

My 86 sr5 transmission is making noise while NOT under a load, I already checked trans fluid level and it was full. While under a load no noises and everything seems normal, as soon as i let off the gas gears make noise while in any gear and neutral. Am I screwed?

[dlb]

sounds like the input shaft bearing. in my experience, when an ISB is bad it will make a grinding or growling sound when the clutch pedal is let up and the engine RPM are low. as it gets worse, the sound will happen through the higher RPM range as well. this is because once the clutch is engaged, the input shaft of the trans starts rotating along with the engine and the worn ISB howls away. the sound tends to go away once you start driving, probably due to increased RPM allowing the shaft to put less strain on the bearing. as the bearing gets more worn out, it will howl more and more.

apparently the ISB can be replaced without removing the trans, although i've never done it on this car. marlinh mentioned it not too long ago.

https://tercel4wd.com/forums/viewtopic.php?f=6& ... ing#p68140

[Petros]

how loud is the noise? how many miles on the trans?

if it is not too loud I would not worry about it too much. when it gets to the point where it is really noisy than see about replacing the trans, rebuilding it or see if the input shaft bearing is all it needs as DLB suggested.

[Tercbeater]

140k miles. It's not excessively loud but is noticeable. Now it's just finding a trans

[dlb]

if it's just the ISB, you won't need to find another trans. check the link i posted.

[marlinh]

Are you sure it's the transmission and not the diff? They can make noises under different conditions: load, cruise and deceleration. I have had front diffs go more times than ISB's. Actually, I haven't ever replaced an ISB. I remove them to make engine installation easier.

[Petros]

presuming the trans was not abused, you might just be over worried about gear noise. the trans will always make a slight gear noise when running, some more than others, but it is likely still within spec. With only 140k miles I would expect that you can double that and much more with just routine maintenance, keeping after leaks, changing gear oil every 30k miles.

The gear noise could be a whine from the drive shaft carrier bearing or the throw out bearing, or the pilot bearing (all will make noise when the clutch is disengaged or in neutral). It might be time for a new clutch, and you can replace those when the clutch finally gives up the ghost. No harm will come from continuing to drive it with the noise, if it does get worse it eventually will get loud enough where the souse of the noise is more obvious.

If it were mine I would keep driving it and not worry about it until it gets so loud you can not carry a conversation with your passenger.

[irowiki]

Would it help to do a ATF/GL flush?

[Tercbeater]

Thanks for the info guys. I'm gonna keep driving it for now. It has all the symptoms dlb described, only noisy at low speeds. I somehow managed to find an earlier model trans locally but no matching diff yet. Been wanting to do this swap for better gearing anyways cause man my car is slow

[xirdneh]

Just thought I'd remind anyone who is thinking input shaft bearing
there are two input shaft bearings
one large sealed bearing, pressed on the aft end of the input shaft, it is easy to replace
and one smaller non-sealed bearing in front of tranny
this smaller bearing is more likely to go bad and not easy to replace
The idea I have is that it is at the highest point of the tranny that receives gear oil
so running low on gear oil make it first to fail

i would think the large sealed bearing would last longer as it would hold the gear oil longer