Blew first gear

[kevinbmx77]

I have a 1994 3.0 manual that i blew first gear apart in. All other gears work, is there a way i can open it up and get the broken bits out so i can keep driving? I cant find a new transmission anywhere around me, and i also dont have a way to get it if i found one

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[RonD]

No, you will have to disassemble the transmission.

1st gear is actually 3 gears, counter-shaft gear, main shaft gear, and dog gear(output shaft), and input shaft gear but if other gears work then that should be OK.
And hard to say which one has failed
2nd, 3rd, 5th and reverse are 3 as well, only 4th with 1:1 ratio isn't

Only access on the M5OD-R1 is thru the top cover, which means pulling the transmission, or you could cut the floorboards away but still don't think that would help you much, although you could ID the problem, maybe.

Google: images m5od rebuild

There are a few rebuild threads with pictures to give you an idea of the layout of this transmission

What does "blew 1st gear" mean?
It isn't there any more?
It grinds when trying to shift to 1st?

 

[kevinbmx77]

No, you will have to disassemble the transmission.

1st gear is actually 3 gears, counter-shaft gear, main shaft gear, and dog gear(output shaft), and input shaft gear but if other gears work then that should be OK.
And hard to say which one has failed
2nd, 3rd, 5th and reverse are 3 as well, only 4th with 1:1 ratio isn't

Only access on the M5OD-R1 is thru the top cover, which means pulling the transmission, or you could cut the floorboards away but still don't think that would help you much, although you could ID the problem, maybe.

Google: images m5od rebuild

There are a few rebuild threads with pictures to give you an idea of the layout of this transmission

What does "blew 1st gear" mean?
It isn't there any more?
It grinds when trying to shift to 1st?

When i put it in first and try to drive it feel like some of the teeth broke off a gear. I didnt try to hard to drive it in first. Just stuck it in second and drove it home. Every gear made noise but i was assuming first was still moving

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[kevinbmx77]

First gear will move the truck but it jams hard enough to stall the truck. I think im just going to have to park it and look for a new gearbox or possibly a manual extended cab with a blown engine for cheap

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[kevinbmx77]

Idk if this helps at all but if its in neutral and i let off the clutch the banging noise will start too

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[RonD]

When the clutch pedal is out ALL the gears are turning, even in Neutral.

Watch this short animation: https://www.youtube.com/watch?v=QPaUJfA1KsY

They call them Dog Clutches but most say dog gears, these are what "grind" if you mis-shift, the 1st, 2nd, ect.... gears are always meshed and always spinning(if clutch pedal is out)

In Neutral all 3 dog gears are in between their specific gears so no engagement of Output shaft(main shaft)

When you shift into 1st you are pushing the 1st/2nd dog gear toward the 1st gear syncromesh which is a softer metal and causes 1st gear to match the spin of the dog gear(output shaft), when speed is matched dog gear locks into the slots/tabs of 1st gear and output shaft is in 1st gear when you let out the clutch.
If output shaft speed is 0 RPMs, truck is stopped, then syncromesh must slow down 1st gear to 0 RPMs so 1st and dog gear can mesh/lock
If clutch disc is not fully disengaged from flywheel it can be hard to get trans into 1st when stopped.

So your noise and issue could be a few things, and trans could just freeze up at anytime, so yes, probably best to park it until it can be pulled and looked at or replaced.
No reason to add a towing bill to the price

 

[kevinbmx77]

When the clutch pedal is out ALL the gears are turning, even in Neutral.

Watch this short animation: https://www.youtube.com/watch?v=QPaUJfA1KsY

They call them Dog Clutches but most say dog gears, these are what "grind" if you mis-shift, the 1st, 2nd, ect.... gears are always meshed and always spinning(if clutch pedal is out)

In Neutral all 3 dog gears are in between their specific gears so no engagement of Output shaft(main shaft)

When you shift into 1st you are pushing the 1st/2nd dog gear toward the 1st gear syncromesh which is a softer metal and causes 1st gear to match the spin of the dog gear(output shaft), when speed is matched dog gear locks into the slots/tabs of 1st gear and output shaft is in 1st gear when you let out the clutch.
If output shaft speed is 0 RPMs, truck is stopped, then syncromesh must slow down 1st gear to 0 RPMs so 1st and dog gear can mesh/lock
If clutch disc is not fully disengaged from flywheel it can be hard to get trans into 1st when stopped.

So your noise and issue could be a few things, and trans could just freeze up at anytime, so yes, probably best to park it until it can be pulled and looked at or replaced.
No reason to add a towing bill to the price

Thank you for all your help, i drove it home when it happened since i was only a half mile away. I will be looking for a new one tomorrow at the junkyard. Merry Christmas btw ?

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[kevinbmx77]

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[kevinbmx77]

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[RonD]

Yup, that looks like a problem

 

[kevinbmx77]

Yup, that looks like a problem

Found a new one at tge junkyard, literally just had to pick it up from next to the truck. Someone pulled tye engine and left it, it was a crashed truck, trans spins good and is almost all the way bavk in tge truck, just need to bokt up my exhuast and crossmember

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[adsm08]

Yup, that looks like a problem

Oh come on Ron, you are too picky. That's good for at least another 5 feet.

 

[kevinbmx77]

Oh come on Ron, you are too picky. That's good for at least another 5 feet.

Five foot toss into the core bin at the junkyard

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[RonD]

Oh come on Ron, you are too picky. That's good for at least another 5 feet.

A little magic oil could fix it................................or maybe not



Replace the 3 rubber plugs for the shift rails on the top of transmission with metal plugs.
It is a common leak point that can cause trans to run low on oil.

Read here: http://www.therangerstation.com/tech_library/shift_rail_plug_maintenance.shtml