Hello,

I pulled the transmission in my '90 4x4 standard cab pickup today to do a clutch replacement. There was also a grumbling/howling noise that happens parked at idle in neutral and while driving (or in any case the clutch pedal was not pushed in) that would go away as soon as I press on the clutch pedal. The noise was gone when I have the pedal to the floor. It comes back when I release the pedal. If I'm doing 60mph under load, the noise will be there. If I push in the clutch pedal and coast from 60mph the noise goes away.

I was thinking the noise was either the pilot bearing or the throwout bearing, but when I looked at the input shaft on the tranny, it wiggles just a tiny bit like about 1/32" or so. If I spin it by hand, there's "noise" but I don't know if it's normal noise or bad noise.

If it's a bearing in the tranny, which bearings are in use while the truck is idling in nuetral? And, are these bearings available for purchase seperately or must I buy a whole kit. I've taken most everything apart before but not trannies, and I wasn't planning on it right now (low funds, no bearing pullers or seperator tools either).

I'm holding off putting the tranny and new clutch in so I don't end up wasting my time having to pull it again, just in case somebody with tranny experience knows whats going on.

Thanks for the help!

sounds like the input bearing.

Originally posted by gnob
sounds like the input bearing.

ditto.
the input bearing is on input shaft...the nose of the input shaft goes into the pilot bearing in the back of the crank.

happy trails
rich *ruger* :usa::beer:

Yep.. they're right..
When it fails it will be a PITA and can screw with the tranny.. IE - the clutch wont disengage the drivetrain...

I learned this one the hard way!

What I have Noticed in the Toyota Trannys going out is Breaking the Teeth and it makes a Stick in a Fan sound.:rolleyes:
Sometimes the t-out bearing will also make sounds like that.
You should be able to tell by pullin it..

I vote for the input shaft bearing, the one under the kidney shaped cover in the bell housing. Fix it now or risk junking the whole tranny later when you bust hard parts. BTW the release bearing for the clutch (throw-out bearing) only rotates when the clutch in engaged (pedal pushed in) so based on your info there isn't much chance of it being that. The pilot bearing makes an intermittent high pitch squeal at idle when it goes out.

Well, based on the info I've heard on this board and others, the culprit is likely not the throughout bearing. Despite that's what I've always been told, it didn't make much sense once I thought about how the bearing works and got confirmation from you when it's actually being used or not. So, I pulled the tranny cover off (it was really easy).

Unfortunately I don't know what to make of what I've found but maybe someone here can help again. The input shaft, however it may be mounted, now wobbles more without the cover in place and the bearing having something to rest on. The bearing balls themselves are covered in blackened oil. Yet, the front bearing on the counter shaft with the roller (needle?) bearings is nice and clear and not covered in black oil. The rest of the gearing and what not only has the colors of the gear oil on it which is not black. Is the black color of the oil coating the input shaft bearing mean it's gotten hot and burned? The bearing seems to spin fine and doesn't bind, but my thoughts are that if it's loose (as the input shaft wiggled with the case on), then it probably wouldn't bind?

Two, The front countershaft bearing.... I can wobble that one if I grab on opposite sides of it and wiggle front to back. It seems to wobble a bit. Maybe it's supposed to, I don't know. At a bear minimum, I'm going to replace these two front bearings. I don't know how or what the input shaft mounts to next to all the gears, but if it's supposed to be rock solid as well, then I will replace whatever is worn there too. All the gears and what not seem to be good, no broken teeth. The drain plug was covered in more than what I normally see of metal goo and some larger flakes but nothing too disasterous yet.

Anyway, if someone could enlighten me on trying to pick out the bad bearing(s) and how and what the input shaft mounts to and if it should wiggle when the case is not on, that would be wonderful. So far, this is much less difficult than I thought.

Thanks for the help!

Anyone know if Marlin's sales force has an E-mail address? I'd like to send an E-mail to see if they sell bearing kits or just single bearings. I doubt I'll have the time to call during the day, plus I don't want to bug them with a phone call with silly questions.

Thanks,

http://marlincrawler.com/

When you hear the noise at idle and it goes away when the clutch is pushed in, it is most likely in the transmission. It is not the release or pilot bearings. To have a bad transmission, it would of made noise in 1, 2, 3, and 5th gear, but less noise in 4th. In netural (truck not moving), only the input and countershaft bearings rotate. The center and output shaft bearings do not turn. All bearings are available seperately, however, when a bearing fails, it sends hardened chips thoughout the trans and could damaged other bearings as well. Drain the oil, check the magnet and inspect the oil for metal.

Marlin,

Thanks so much for the response! You described the problem to a T. The tranny makes noise in 1, 2, 3, and 5, and less in 4th (almost can't hear it at all). It seems to make more noise/different noise in 5th.

And, I think you've answered my last pondering thought--if the transmission is in neutral, what bearings are involved? Spinning parts must cease somewhere in the tranny when in neutral, and those parts must no longer be under load or making noise.

If I understand you right, it's just the two bearings (front counter shaft and front input shaft) that are functioning when in neutral. The drain plug looked pretty good. There was a slight amount more build up on it, but it was just the gray sludge. There wasn't any chunks on it or anywhere else in the tranny (the rest looked really good). Only the input shaft bearing had discolored blackened oil stuck to it.

Thanks for everyone's help!

Another big thanks to Marlin and his crew! I finally got a chance to call him up today, and he was able to tell me what I needed to do, gave me some excellent pointers, and then I placed an order for the parts I needed. I can't wait to get the parts and get a quiet transmission again! Marlin went far beyond what most people would do to help me, and I greatly appreciate it. I can see why he has such a good reputation.

All that's left now is to get the new parts installed and the tranny back in. I'll post a followup when I'm done, and if I can get a good shot I will post pics of the bad bearing (input shaft bearing).

Thanks!