68RFE Sticks In Neutral

Hey all, this is my first post for help on the form, so please let me know if I should change anything with my post.

I have some knowledge when it comes to Cummins engines, but I am a pretty novice with auto transmissions and tuning general.

To start, I bought my truck already deleted and tuned.

The previous owner had his buddy in a small town shop do the tuning, so I have no idea how good it is.

The truck runs and drives fine, but the shifting is pretty harsh.

It sometimes jumps around a bit after a shift, it's completely random and fairly rare when it does, but the biggest problem is that when the 68RFE is shifting from 2nd to 1st when coming to a stop, the transmission will stick in neutral.

If you start to slow to about 10 mph and hit the pedal, it will just free rev.

Then the CEL will come on with a gear ratio error.

Shut the truck off and open the door, and put it in drive, and you are good to go again.

The strange thing is, if I use the gear selector to tell it to shift to first at about 8 mph, it will do that no problem.

Then put it back in drive, and off you go.

There is more shift flare between 1st and 2nd than any other shift.

I am not sure if this is tuning related or valve body or the whole transmission is toast.

If I totally come to a stop-in drive, sometime, it will find 1st but with an aggressive clunk and the truck's lurch.

Did anyone hear of this?

I have changed the fluid, the filters, the input and output speed sensors, the pressure sensor, and the solenoid pack with no change.

Thanks for any help or experience anyone has!

Not sure if Ray @DRD has heard of anything like this caused by a bad tune before.

I was thinking about getting a tune from Ray anyway, so I know it is solid.

It's tough to troubleshoot anything when you don't know how much the tune is screwing up.

Quote:

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Originally Posted by Ferds

Not sure if Ray @DRD has heard of anything like this caused by a bad tune before.

I was thinking about getting a tune from Ray anyway, so I know it is solid.

It's tough to troubleshoot anything when you don't know how much the tune is screwing up.

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That almost sounds like a locking shift which is miserable on a stock trans and very bad for it.

It really sounds like bad tuning for us, but once tuned, DRD would usually be able to tell you, friend.

God bless,
igotacummins

So won’t engage 1st unless you manually put it there?

If so you probably broke the one way clutch.

If you got gear ratio codes you have something slipping it’s going to be a trans issue.

You still need to get good tuning.


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Quote:

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Originally Posted by Chrisn162001

So won’t engage 1st unless you manually put it there?

If so you probably broke the one way clutch.

If you got gear ratio codes you have something slipping it’s going to be a trans issue.

You still need to get good tuning.


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Well it will engage 1st if basically come to a full stop.

Then it lurches in.

Most times I just manually shift it so its smoother.

I am going to order a tune from Ray and load it on the truck.

Is it worth reach out to him before to explain the issue or just order it and flash the tune.

If so, what's the best way to contact him?

Quote:

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Originally Posted by Ferds

Well it will engage 1st if basically come to a full stop. Then it lurches in. Most times I just manually shift it so its smoother.

I am going to order a tune from Ray and load it on the truck. Is it worth reach out to him before to explain the issue or just order it and flash the tune. If so, what's the best way to contact him?

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I believe what @Chrisn162001 is saying is because you are receiving a transmission trouble code this indicates you have a problem with your transmission.

I would check with DRD prior to ordering a tune.

To contact him follow this link.

https://www.igotacummins.com/threads...)-Coupon-Codes


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit and 50 Gallon auxiliary fuel tank.

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I got my new tune from Ray loaded up yesterday.

Well worth the money.

The shifts points are so much better timed and truck just came alive compared to the old tune.

Unfortunately I am still having the neutral stall issue from 2nd to 1st.

It seems better.

When I let the truck shift on its own at a stop the lurch was much less but if I try to take off from a 7 mph roll it still free revs.

Even when manually shifting the shifts are smoother from 2nd to 1st so that's good.

Love the tune but I still have a hurt transmission I guess.

I only drove for a few miles, the relearn hasn't finished yet but I doubt it'll change much.