transmission: second opinion

[4Runninfun]

I think I have a transmission on the way out. For a while now I've noticed some vibration in the transmission shifter knob. It was never that bad but always in the back of my mind. Moving forward, last sunday we packed the 4Runner for moab and headed out immediately noticed a stronger vibration. I chocked it up to the tires having sat for a few weeks. We stopped for coffee in woodland park and I was doing a walk around and rocked the truck and heard some clinking coming from somewhere around mid transmission. So we decided to head back to check things out. While driving around at home with the truck unloaded I noticed that I could feel a strong fast vibration in the transmission stick, similar to when a bearing is going out. When holding the t-case stick you could still feel some vibration but much less.

When I got back to the house, I pulled the drain plug on the transmission. The fluid came out dirty, but nothing out of the ordinary. Looked at the magnet in the drain plug, definitely some metal enough to create a small dome. Not great, not bad. I decided to go ahead and pull the tranny. When I got it out, went ahead and pulled the rear half of the case off. I found a little more grit but again nothing screaming a problem. When looking at the gears however there are some worrying signs. 3rd and 4th have some uneven wear and chipped gear teeth. I'm also seeing 5th with some significant chipping. Additionally, when turning the input shaft there does seam to be some bearing wear further inside the front half of the case.

I also took a look at the clutch pilot bearing. Which turned out to be bad, which is especially bad news because that bearing only has a couple thousand on it.

So I'm looking for a second opinion. Is this transmission done? Can it be pushed until the fall? What are some other thoughts?




Reverse

http://i23.photobucket.com/albums/b367/4runninfun/DSCN0089_zpsd8cce1cb.jpg (http://s23.photobucket.com/user/4runninfun/media/DSCN0089_zpsd8cce1cb.jpg.html)

http://i23.photobucket.com/albums/b367/4runninfun/DSCN0088_zps13a05542.jpg (http://s23.photobucket.com/user/4runninfun/media/DSCN0088_zps13a05542.jpg.html)

uneven wear and chipping 4th and 5th

http://i23.photobucket.com/albums/b367/4runninfun/DSCN0085_zps7315f69e.jpg (http://s23.photobucket.com/user/4runninfun/media/DSCN0085_zps7315f69e.jpg.html)

http://i23.photobucket.com/albums/b367/4runninfun/DSCN0081_zps8cc008cc.jpg (http://s23.photobucket.com/user/4runninfun/media/DSCN0081_zps8cc008cc.jpg.html)

3rd

http://i23.photobucket.com/albums/b367/4runninfun/DSCN0080_zpsb5efe2ac.jpg (http://s23.photobucket.com/user/4runninfun/media/DSCN0080_zpsb5efe2ac.jpg.html)

http://i23.photobucket.com/albums/b367/4runninfun/DSCN0076_zps627c6ec8.jpg (http://s23.photobucket.com/user/4runninfun/media/DSCN0076_zps627c6ec8.jpg.html)

[CS79bronco]

I would think the bearings & maybe shafts have enough wear to let the gears be mis-aligned enough to wear unevenly. I used to drive Toyotas where I worked in the 80s & 90s. Put an average of 1k miles a week. They traded them in from 160k to over 200k. Only one that ever had tranny problem did what yours is doing, at 59,900 miles it started jjumping out of gear. By the time I got it in to the dealer it had rolled over to 60,010, out of warranty. Since we bought several pickups from them, they rebuilt it under warranty anyway. They replaced all bearings, synchros, shafts & gears. That truck went another 120k before it was traded in, still shifting great & no noise.
So to answer your question, IMHO, as long as it doesn't jump out of gear you can run it till it breaks. Even then, depends on which gear & how much it worries you. But it would be a good idea to look for a replacement & have it on hand for when....not if. I would not trust it to make a long roadtrip unless you have someone with a trailer along, or available to get you back home. Or a spare tranny & tools in the back.

[4Runninfun]

So to answer your question, IMHO, as long as it doesn't jump out of gear you can run it till it breaks. Even then, depends on which gear & how much it worries you. But it would be a good idea to look for a replacement & have it on hand for when....not if. I would not trust it to make a long roadtrip unless you have someone with a trailer along, or available to get you back home. Or a spare tranny & tools in the back.

And that's the catch, I wheel alone all the time. I never like to take a truck out that I feel could pose a significant problem. If the issues above are just a 28 year old truck and nothing too major I'll bolt everything back up and run it. But if this is the beginning of the end then I'll find a replacement. I've never torn down a tranny before so I have limited knowledge on what is normal wear.

[CS79bronco]

I forgot to ask earlier, did you check the u-joints? That could be causing the bad vibes, & also clicking when rocking it back & forth. They may look OK but when you wiggle & shake them you may feel movement, or even shake out some rusty powder. If they even show a tiny bit of rust at the caps replace them before they get real bad. The u-joints would probably vibrate more with all your gear loaded in the truck too. The gear wear is probably from many miles. If one or more of the bearings is going out it should have movement that you can feel by moving the gears & shafts. A bearing would probably cause vibes & noise more than gear wear.

[4Runninfun]

My first thought was u-joints. When rocking the truck I didn't notice any movement or clicking in them. Before reinstalling the drive-shafts I'll definitely be double checking them.

As far as shaft play, there is some but wasn't so much that it was alarming.

While I was tearing apart the tranny, I was hoping to find a smoking gun. Gear tooth missing, large amount of metal in the oil, something that was a definite sign. But all I've found is a bunch of small stuff.

[tonkatoy]

what speed are you getting the vibrations at.

[4Runninfun]

30-35+

[tonkatoy]

sounds like a driveshaft.

[4Runninfun]

When you say driveshaft do you mean the u-joints, or the actual shaft?

[4Runninfun]

Moving forward, I pulled the other half of the case off. More of the same except now I can move the lower shaft (I believe it's called the counter shaft) 1/4" side to side. I'm looking in the FSM now to find out what spec is but it seams like an awful lot.

[CS79bronco]

1//4" does seem like a lot, I would guess .5mm or less, or 10-15 thousandths, with new gears & bearings.

[Funrover]

Moving forward, I pulled the other half of the case off. More of the same except now I can move the lower shaft (I believe it's called the counter shaft) 1/4" side to side. I'm looking in the FSM now to find out what spec is but it seams like an awful lot.

Yikes, that is a lot of play. But does part of that play come from a support in that case that is now removed? Or does the case being absent not make a difference?

[4Runninfun]

there is a bearing on one side of the case that supports. So it's not all relying on the center bearing.

[Fordguy77]

Gears don't look fantastic, but they don't look so bad. I'd personally buy the fsm and start checking thrust specs, as well as tolerable backlash, and if things are out of spec, replace as needed. But I would recommend all bearings and seals why the transmission is so far apart.

if you don't feel comfortable doing it yourself, many transmission shops will rebuild a manual transmission that's already pulled at largely discounted rates. I paid $600 a few years back to rebuild my t18 and a np208f and paid $800 for my m5r1 and bw1354m which needed 1st, 2nd, and reverse gears replaced.

[4Runninfun]

Well, what I wound up doing is grabbing another transmission off of CL for $150 and that even included the t-case and front DS! The guy said it had quite a few miles on it but didn't make any noises or vibrations. I spent the day putting this transmission in. I still have a few things left to button up tomorrow, and then test things out.

Fordboy, after doing some other research I agree with you (and others) the gears really aren't all that bad. I suspect the bearings are the culprit and that is what was causing the vibrations, and bad wear patters. I could have taken it to a shop but at $600 on the low end spending $150 right now made more sense. This gets my truck back up and running for the summer. This winter I might see if I can put aside some cash and get myself an R151f transmission. Which would be an awesome upgrade.