Transmission 68RFE Curiosity Questions

[JDC]

I've been curious about my transmission after getting into my weight loss program about a year ago.

2012 Dually, max tow, 4:10, 68RFE, white 110k miles.

I will admit the relearning process was not ultimately achieved, so this might be some of my concerns.

The trans worked great before and still performs well.

I am unsure if this is normal or if my trans is going out.

Hoping some of you could give me some of your thoughts.

- When accelerating slowly, the truck will "lunge" when shifting; sometimes, it shifts hard, and you feel like someone kicked the bumper.
- Accelerating from 50-75% throttle shifts quickly and smoothly.
- I understand shift flare and why, but it will flare, then shift, then act as if you are riding the clutch for a second or two before it engages fully.
- In tow haul, 4th gear will only hold for about 2 seconds then quickly shift to 5th, but 3rd gear will hold until 2400 rpm no matter how much throttle.
- While shifting down from 2nd to first, it waits until I almost stop, then shifts to 1st. This pushes the truck (not through the brakes, but it's annoying).
- Each shift is like described above, where it is not smooth; it either hits hard or feels like you are slipping the clutch if it was a manual, but the clutch popped, and the gear is too high (if that makes sense).

The trans just has not been smooth, and I have put several thousand miles since the modification.

I see average temps while driving or towing, respectively, and do not have any slip while pulling the camper, 15k.

I am just concerned I am losing the trans but hoping a relearning would be the first place to start.

It's always hard to explain what you feel and hear in your own vehicle, but I want a smooth-shifting trans again.

Thanks for any help or insight you can share.

JDC

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[AK Bob]

I've been curious about my transmission after getting into my weight loss program about a year ago.

2012 Dually, max tow, 4:10, 68RFE, white 110k miles.

I will admit the relearning process was not ultimately achieved, so this might be some of my concerns.

The trans worked great before and still performs well.

I am unsure if this is normal or if my trans is going out.

Hoping some of you could give me some of your thoughts.

- When accelerating slowly, the truck will "lunge" when shifting; sometimes, it shifts hard, and you feel like someone kicked the bumper.
- Accelerating from 50-75% throttle shifts quickly and smoothly.
- I understand shift flare and why, but it will flare, then shift, then act as if you are riding the clutch for a second or two before it engages fully.
- In tow haul, 4th gear will only hold for about 2 seconds then quickly shift to 5th, but 3rd gear will hold until 2400 rpm no matter how much throttle.
- While shifting down from 2nd to first, it waits until I almost stop, then shifts to 1st. This pushes the truck (not through the brakes, but it's annoying).
- Each shift is like described above, where it is not smooth; it either hits hard or feels like you are slipping the clutch if it was a manual, but the clutch popped, and the gear is too high (if that makes sense).

The trans just has not been smooth, and I have put several thousand miles since the modification.

I see average temps while driving or towing, respectively, and do not have any slip while pulling the camper, 15k.

I am just concerned I am losing the trans but hoping a relearning would be the first place to start.

It's always hard to explain what you feel and hear in your own vehicle, but I want a smooth-shifting trans again.

Thanks for any help or insight you can share.

JDC

I am sure others with 68RFE experience will chime in.

One thing you could try is another relearn by returning to stock and reload your tuning.

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[ricky_bobby]

With 4.10 gears, you are taking some of the stress off but with 110k miles and especially if a good amount of towing.

I think you would be doing for service/valve body overhaul, or at least doing a quick relearn and trying to make it learn again.

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[kgharrin]

Is DRD your tuner?

My comments will be assuming he is.

Otherwise, the shifting and lockup strategy may differ.

Addressing some of your thoughts 1-6:

1: Sometimes, the TCM will do this if under the right conditions, and it usually is under light to moderate throttle. I notice it mostly goes from 3rd to 4th, and it will essentially go right from unlocked TCC 3rd --> Locked TCC 4th. Usually, it will shift from unlocked TCC 3rd --> unlocked TCC 4th --> Locked TCC 4th to smooth it out, but when it quickly locks the TCC in 4th after the shift, it feels more abrupt. I understand this to be normal.

2. Good

3. It sounds to me like the TCC is just re-locking after the shift. If there is a slip across the converter when it starts to lock up, it will feel like you are slipping the clutch (because you are). As long as it isn't excessive, it sounds normal to me

4. It seems a little high of a shift point if you are under light throttle and cruising at low speeds; does it only do that in tow/haul? Tomorrow I'll check what RPM mine will shift to 4th under light load - maybe others can comment if this is normal.

5. The shifting down from 2nd to 1st only at low speeds (<10 mph) is normal. The pushing the truck part is interesting; is it in all conditions or just tow haul? Is your TCC unlocked during this time?

6. No comment.

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[JDC]

Thanks for the comments.

Yes, DRD tuned.

I haven't tried the re-learn process yet, but I think that is my next step.

I might not have been too clear, but the only scenario described above in tow haul would be the quick shift out of 4th; the rest would be without tow haul on.

Again thanks for the comments; I'll get the re-learn complete and check back in.

It just doesn't seem as smooth and precise as most state on here when they get tuned, or maybe I'm picky.

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[ricky_bobby]

For what it's worth, it probably took about 1000 miles to settle in completely, and the truck drives differently in Tow/Haul vs.

T/H off than before.

After driving around lately, it is holding gears better without T/H than it used to.

I also changed my exhaust brake to Auto operation instead of full, which made a difference in shifting behavior.

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