85 Bronco II 5 Speed

[Tuckerdee]

I have an '85 Bronco II with a 5 speed. I believe this is a Mazda transmission? It makes a rhythmic ticking/knocking noise, which varies with engine speed, in every gear but 4th. Noise goes away when clutch is depressed. So I'm pretty sure it's a bearing in the transmission. Any ideas? Thanks much.

 

[mjonesjr]

you could have one of three transmissions in your truck. Either a FM-145, a FM-146, or a Toyo Kogi.

 

[Bruce]

Yep sounds like either a cluster gear bearing or input shaft pilot bearing going bad or is bad.

 

[Tuckerdee]

From illustrations I've found, it sure looks like a Toyo Kogyo unit. I also forgot to mention, it makes the noise while idling in neutral as well. Which leads me to think it's the "pocket" bearing or needle bearing on the main shaft and not a cluster gear bearing since I don't think that would rotate in neutral.

 

[Jspafford]

The input shaft bearing will make noise with the clutch released in all gear except 4th, and when in neutral with the clutch released.

 

[Hahnsb2]

Yeah it should be a TK5.

 

[Jorley]

The TK5 uses a split shaft design. The main shaft rotates on the the input shaft. There is a needle bearing there.
The 2 shafts rotate at different speeds in all gears except 4th. In 4th the 2 shafts are locked together. The only time there is no load on the needle bearing is in 4th.
The cluster gear meshes with the input shaft so spins any time the input shaft is turning.

Here's a pic of the TK5. The input shaft and needle bearing are on the left.This doesn't show everything inside of one,just the gears mostly.

 

[Tuckerdee]

Thanks for that photo. I have also found conflicting info on what lube to use. Some sources say 80w-90, others say ATF. Which is it?

 

[MAKG]

It's hosed. Why do you care?

Putting the correct lubrication (GL-4 gear oil) in will not put steel back in the bearings.

FYI, the needle bearing is one of several possible faults here, and even if that is the problem, it is exceedingly unlikely to be the only casualty. 4th gear is VERY different than any other gear in many respects. Especially, the cluster sees insignificant transverse stresses in 4th, and substantially larger stresses in any other gear.

About the only way to hose that particular bearing is oil starvation. Other bearings mentioned (especially in the front of the transmission) can "spin" and get hosed up much more easily.

 

[Tuckerdee]

It's hosed. Why do you care?

Putting the correct lubrication (GL-4 gear oil) in will not put steel back in the bearings.

FYI, the needle bearing is one of several possible faults here, and even if that is the problem, it is exceedingly unlikely to be the only casualty. 4th gear is VERY different than any other gear in many respects. Especially, the cluster sees insignificant transverse stresses in 4th, and substantially larger stresses in any other gear.

About the only way to hose that particular bearing is oil starvation. Other bearings mentioned (especially in the front of the transmission) can "spin" and get hosed up much more easily.

Why do I care!? I care because if I choose to rebuild the transmission I would like to have the correct lube in it! I care because I desire to live in a non-throw-away society. I care because I'm trying to help out a buddy that doesn't have a lot of cash to work with in trying to get his ride back on the road. Sheesh! I'm perfectly aware of the basics of metallurgy and the effects that lube starvation can have on bearings. I was trying to do some trouble shooting for a friend that has this vehicle. Maybe somebody put the wrong lube in it at some point. Just saying "it's hosed" is not helpful at all.

BTW, I'm a long-time member of a Dodge Diesel forum, and your sort of response would NEVER happen there.

I'll not be back here!

 

[Hahnsb2]

Why do I care!? I care because if I choose to rebuild the transmission I would like to have the correct lube in it! I care because I desire to live in a non-throw-away society. I care because I'm trying to help out a buddy that doesn't have a lot of cash to work with in trying to get his ride back on the road. Sheesh! I'm perfectly aware of the basics of metallurgy and the effects that lube starvation can have on bearings. I was trying to do some trouble shooting for a friend that has this vehicle. Maybe somebody put the wrong lube in it at some point. Just saying "it's hosed" is not helpful at all.

BTW, I'm a long-time member of a Dodge Diesel forum, and your sort of response would NEVER happen there.

I'll not be back here!

Good for the Dodge Diesel forums . I fail to see what is so wrong about MAKGs post, from your post it sounded like you were going to just add lube and keep driving as you didn't mention a rebuild so he was just trying to help you out by saying it's toast and it won't last, because believe me, there are plenty of people that come on here who have no idea what they're doing. :icon_idea: Add more info to your posts so others can respond accordingly, otherwise don't expect the answers you're seeking.

 

[Jspafford]

Four posts, all in the same topic, and already complaining about the free help.

Who here gets paid to help another out?

Not me.

 

[Hahnsb2]

Four posts, all in the same topic, and already complaining about the free help.

Who here gets paid to help another out?

Not me.

+1!
While you're at it you can run back to your other forums and be sure to post about how we are all so mean for trying to help you on our personal time without getting paid. If you think it's so bad here, hang out at Pirate for 10 minutes.