Transmission issues

[PipeHitter]

Looking like I may need to replace my transmission. Purchased the truck and drove it 6 hours home with no issues. Had whipple update my tune a few months ago. Upon flashing the updated tune I noticed that the truck certainly seemed more aggressive and lively. So much so that I had to remove the pedal commander the previous owner put on before I could even get out of the driveway. I noticed some shuddering while driving around and shifting that was not there before.

I asked whipple about it, and they had me re-route a vacuum line that did improve drivability quite a bit, however I still noticed a slight amount of shuddering between 3-4, and sometimes it felt like the transmission skipped a bit while shifting 3-4 under moderate acceleration. There are other little 'pulsating' or shuttering/stuttering type sensations sometimes while shifting, and I felt I noticed it while just coasting around. I thought I still had some sort of vacuum issue, so ordered a smoke machine to try and track it down. Never managed to test that theory as things got worse.

Took about an hour drive on the intestate and had 5th gear slip for the first time. I noticed the dash flash down to 1 gear then jumped back into 6th, skipping over 5th. If I attempted to force a downshift (like in passing) 5th gear would slip, the truck buck a lot, and then skip back up to 6th. Thought it might be a lead frame issue.

Drove the truck a week or so back and forth to work (about 10 min each way) and it seemed ok. Still had the above mentioned shuddering. Then took a longer trip (1.5) on the interstate and the truck repeated the 5th gear issues only now its consistent. As in 5th gear is not usable, either upshifting or down shifting. Again I suspected lead frame issue, exacerbated by heat driving down the interstate.

Not lead frame related, or valvebody/solenoids as I've replaced all three. And now 5th gear is always jacked. No need to ge ton the interstate. So issue had progressively gotten worse.

So, it may be new transmission time. Does anyone know, or have any experience with:

1.) As I just had my tune updated from whipple. Any chance this could be tune related? I don't think it is, and probably just coincidence. But still want to be sure.
2.) Can I just swap in a different transmission (of the same model) considering the truck is not on a stock tune? Are any programming changes needed on Whipple's end?

Thanks in advance.

edit: forgot to mention the code that triggered: p0735 "5th gear incorrect ratio"

 

[Guardrail]

Wasn't there a recall on the output shaft speed sensor that caused the 6th to 1st shift n the highway? Worth a shot changing that. If the computer is getting the wrong info it would shift crazy

 

[New recaros]

Have you tried going back to stock on the trans tuning

 

[mprice1234]

^^
I agree that this would be the best thing to do before tearing into the trans or replacing it.

 

[FordTechOne]

So it has a Whipple supercharger? Slipping in a specific gear ratio is unlikely to be a tuning issue, especially with P0735 setting. 5th gear is achieved by applying the Direct (B) and Overdrive (E) clutches. The direct is also used in 3rd gear and reverse, while the O/D is used in 4th, 5th, and 6th.

You could have it overhauled, but if you have a power adder it really needs to be upgraded to hold the additional load. The factory unit is only designed to handle the stock engine power output.

 

[MTF]

Check the harness from the PCM down to the tranny, make sure nothing is burnt by the exhaust.
Now, not knowing how the previous owner drove the truck with the pedal commander is a concern.
He or she could have had it at the highest setting and just harmed the tranny.

Do you know the shop that did the tranny work and trust them?

Ford Tech One is incorrect with stock tranny not handling the extra HP and Torgue.
Unless you go overboard with the Tune or bad Tune.
You did state it's the Whipple Tune, so you're good.

 

[BSouders80]

for sure check what @MTF said on the harness. Happened to me.

I’ve read to where one guy went and got a 6R80 from a junkyard while his tranny was being built. Worked just fine. Just got to update the strategy in Forscan.

I sent my transmission to MS Racing for rebuild. If I had to do it all over, I’d send it to Circle D. Longer lead time but in totality, would have been much quicker in the long run.

 

[FordTechOne]

Check the harness from the PCM down to the tranny, make sure nothing is burnt by the exhaust.
Now, not knowing how the previous owner drove the truck with the pedal commander is a concern.
He or she could have had it at the highest setting and just harmed the tranny.

Do you know the shop that did the tranny work and trust them?

Ford Tech One is incorrect with stock tranny not handling the extra HP and Torgue.
Unless you go overboard with the Tune or bad Tune.
You did state it's the Whipple Tune, so you're good.

No, you are incorrect as usual, because you don’t know anything.

P0735 is not a circuit or component code, it’s a conditional code. It sets when the PCM detects 5th gear ratio cannot be achieved. Slipping in 5th gear validates that condition.

The 6R80 was never designed to handle more power output than the stock engine. You have no idea how it works and you’ve never had one apart, so your comments and claims are irrelevant. One of the most common failures when putting more power /torque through it than stock is failure of the planetary carrier thrust bearings. The clutch holding capacity is also a weak point when exceeding stock power levels. Cranking up line pressure and shift speeds through a tune is just a bandaid to try and prolong failure.

 

[MTF]

No, you are incorrect as usual, because you don’t know anything.

P0735 is not a circuit or component code, it’s a conditional code. It sets when the PCM detects 5th gear ratio cannot be achieved. Slipping in 5th gear validates that condition.

The 6R80 was never designed to handle more power output than the stock engine. You have no idea how it works and you’ve never had one apart, so your comments and claims are irrelevant. One of the most common failures when putting more power /torque through it than stock is failure of the planetary carrier thrust bearings. The clutch holding capacity is also a weak point when exceeding stock power levels. Cranking up line pressure and shift speeds through a tune is just a bandaid to try and prolong failure.

You're just the greatest, I guess your parts book tells you that, you never disappoint. LOL

It has maximum HP of 600 a maximum torque capacity of 570 ft. lbs., stock.

 

[mprice1234]

Here we go again!