My second M715 build. What was I thinking?

[jeeper]

I pulled the top cover off after work today and tried to tell why the transmission is not in neutral.

https://youtu.be/Sz33gz0oNEU

This video shows what I'm looking at.

I've tried moving the shift rings back and forward but am unable to find a location that the transmission is actually in neutral.

[jeeper]

So I've been trying to figure out what is going on with this transmission. I've drained the oil tonight. Tomorrow I hope to pull the tail piece of to inspect in there. I've read quite a few posts of the NV4500 getting stuck in 5th gear. Mostly it I've read it has been the Dodge tranny but...I'm guessing that must be what gear this transmission is stuck in.

[ray steadward]

I thought the Cummins transmissions usually stripped 5th gear.....

[67smith]

So the issue is the 5th gear retaining nut- fifth gear isn't fully spliced so extreme vibrations will eventually cause fifth gear to fall off-if you happen to be in fifth you could get it stuck.

This issue though has me a little perplexed, without the top cover on you should be able to find neutral pretty easy, and that would point to issues with the shift rails in the top.

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[Mikel]

I thought the Cummins transmissions usually stripped 5th gear.....

I think that as frequent as quadrajets leaking through the well plugs. It probably happens 1/100000 as often as it is mentioned

[Mikel]

I thought the Cummins transmissions usually stripped 5th gear.....

I think that as frequent as quadrajets leaking through the well plugs. Everyone has heard about it, but it's hard to find people who have actually witnessed it

[jeeper]

Well I've got the tail piece off the transmission. I didn't need to pull the transmission to do that. Even with the tail piece off I can't figure out what is wrong.

I can slide the shift rings freely on every combination I can get them into but every combination I can find still isn't neutral. I can see four slip rings. I believe they are in order from front to rear such that the front ring shifts first and second? The second one back shifts third? Third one back shifts fourth and the rear ring does fifth and reverse?

There must be something out of adjustment or worn out?

I've never rebuilt a transmission before and am not really wanting to try.

I'm just about ready to give up on this transmission. My problem is my project funds don't allow me to get this rebuilt. And I don't really have enough right now to go buy another used transmission. I am not really willing to take a chance on another used one anyway unless I can see it operate first.

The seller of this transmission seemed to be a stand up guy. I may see if he's willing to help me in any way.

[Von]

Man it really sucks that you're stuck in Transmission Hell, I want to see your truck on the road.

Watched your video a couple dozen times, even slowed it down to 1/4 speed trying to sort it out. No help at all, but the engine sounds weird with the video at half speed.

Might have a worn synchro ring stuck to a gear. That would be a lot easier to diagnose if the trans was out and on a bench.

I just rebuilt the old T10 4 speed in my Fairlane. My first transmission rebuild.. easier than I thought it would be. Not a "breeze" though.

[Mikel]

I pulled the top cover off after work today and tried to tell why the transmission is not in neutral.

https://youtu.be/Sz33gz0oNEU

This video shows what I'm looking at.

I've tried moving the shift rings back and forward but am unable to find a location that the transmission is actually in neutral.

It's hard to see from the video. I wonder if something is wrong with the shift tower (forks out of alignment?) so that the transmission does not go into neutral when the shifter is in neutral.

But yes, you should be able to slide the rings and put them all in a disengaged position. Don't give up! I bet it's something simple.

[jeeper]

Thanks for the moral support.

I decided I may as well remove the transmission since it was only 4 more bolts and a hydraulic line left to make it easier to see inside the transmission.

At this point I have the transmission out with the top off, the tail piece removed and both PTO covers removed.

I am studying the exploded view I found here.

What I'm having trouble figuring out is where the shaft should be split to ensure that the input shaft can not turn the output shaft. It seems logical that something is either jammed or broken to not allow the output shaft to turn free from the input shaft.

I've tried calling a few salvage yards and a couple transmission shops to see what it would cost to bring it in even though I have no budget to do that at this point. I was quoted in the $2000 range for a rebuilt transmission with exchange from a couple shops locally. None of the salvage yards I called even have one to sell me so they wouldn't even give me a price.

It looks like my option is to dive into this at this point.

It already doesn't work the way it is. I guess there is a chance I can break something internal to the transmission but that won't make it any less usable at this point.

If I look at it optimistically I may actually figure out what is wrong and be able to fix it so I can use it.