Gettin real sick of this..

[Iceman21]

Facts: 87 bronco 2 2.9/fm145/bw1350
I just had my trans rebuilt this spring, and last night it bit the big one on me. I started my bronco up and drove 5.6 miles going through all gears and everything was perfectly normal. As I slowed down from highway speeds I shifted into 2nd, and had a decently load gear noise coming from my transmission (under 2 grand is when I could hear it) and it seemed to follow with my rpm's... When idling it went away, then I would take off and it (as in the noise) would pick up with the rpm's then it would vanish around 2,000 Rpm ( not sure if exhaust tuned it out or it actually went away) then I drove another 1 mile on the highway going 52 mph I gently stepped on the gas pedal and fifth gear turned into nuetral. (no crack bang boom thud noises, just a solid yet subtle separation noise) It didn't kick into neutral shift position, it stayed where it was but it was in complete nuetral. I shifted into 4th and prayed i'd make it home. (9 miles) as I approached my house I tried 3rd and it worked smooth just like 4th did. When I tried 2nd I got all sorts of funny swirling and satisfying fringing noises but it engaged the gear then it was smooth, then I went to first and that worked as well. Taking of from the stop sign, I went to shift into second and it wouldn't go. Now, it will not go into any "shift slots" other then 3rd and reverse. It is stuck in 1st gear and will not engauge neutral. When I put it in "reverse" it engaugs 4th gear. So ergo 1st all the time unless moved into reverse then it's in 4th. Yet 1st gear still works PERFECTLY fine and I'm getting no scary noises anymore it just won't shift... Please help, I have no idea what to do at this point.

 

[Spott]

Well, the good news is, your problem is probably limited to the overdrive gearset, and that's not too hard to get to once you get the tranny out of the truck.

The bad news is that you're gonna have to get the tranny out of the truck.

I rebuilt my FM146 the summer before last, so I'm pretty familiar with the guts of those mitsu's.

The OD gears are the weak link in those transmissions, and they're designed in such a way that they're in a weak location, too. I suspect it started with one of the screws (that hold the reverse support plates to the tranny body) backing out a hair, rubbing against the reverse gear, and causing the grinding noise. As it vibrated and scraped, it finally caught the gear solidly, and grenaded the OD gear or the mounting, causing the "neutral" behavior. Finally, chunks of the OD gear assembly got wedged into the shift rails, blocking some gears, engaging others, and generally causing it to not shift properly.

This may be a problem that the tranny shop that did the rebuild would be responsible for, but it would be impossible to know for sure until you can see what happened in the OD-R gear space.

It can be fixed in your garage, if you wish. If not, disregard the remainder of this post. If so, you must remove the drive shafts, then the TC lever and the TC, then the shifter assembly and the clutch line, and finally the tranny. The worst part of removing the tranny is the exhaust pipe running underneath it. It likes to bind between the transmission tunnel and that pipe. Sometimes jacking the engine a little helps.

Once you get the tranny out, take off the shifter housing; watch out for the reverse lockout. Take a couple plugs out and drive two roll pins out of the shift gates. Take out the neutral return springs, and then move the main shifter lever all the way back. Flop the shift gates out of the way, and take the rear housing off of the tranny. This will expose what remains of the OD gearset, in all it's mangled glory.

If you're a lucky boy, only the OD gears are damaged. It's possible that the reverse gears got involved too, as they live in the same space, and also the OD-R shift assembly. Any damage should be obvious. You shouldn't have to worry about the 1-4 gears inside the tranny housing, but you should take the access plate off the bottom and clean out any debris, and give it a good inspection.

At this point, there are a lot of possibilities, so I won't offer further instruction until we know what the problem involves.

Feel free to ask for clarification on any step as you come to it, I'll answer the best I can. The FM146 I have the manual for, and the FM145 you have, are fairly similar, but there are a few differences. It will probably require a full day to get the tranny out and disassembled, and another to get it back together and re-installed once you get the parts, if you're working alone.

Hope this helps!

Spott

 

[Iceman21]

I really appreciate your info. I will be getting started on the job tomorrow and I'll keep this post updated with what I find. I have taken one of these transmission out before so at least I'm semi competent. But I'll have a look hopefully by the end of tomorrow and let you know.

I need to get my bronco to my shop which is three miles away... Can I limp it there?

 

[Spott]

If you don't hear any grinding noises, it's not a problem.

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[Iceman21]

The guy who rebuilt it didn't really tighten anything.... The lock on the rear tail shaft let that bearing slip and just all went to hell.... Buying a new one. Thank your info tho.

 

[Spott]

No problem. If it were me, I'd make the shop that did the rebuild pay for repair or replacement, and have the work done elsewhere.

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