Tranny question

[tpearia]

Just got my FU installed on my truck, and I noticed, especially with some of the more aggressive tunes, when shifting the tranny seems to sort of slide down in the rpms a bit before hitting the next gear quite hard.

I was wondering if this is just sort of how these trucks react to an aggressive tune, like maybe part of the tune, or if its just a product of a tired tranny.

Thanks for any input!

[rammertide07]

How agressive of a tune are you talking about? Have done any mods to the tranny (shift kit/torque converter)?

[tpearia]

Its a 140 tune, on a stock auto tranny.

[tpearia]

Check that, it does some fairly erratic stuff on all the the tunes. Wierd.

[rammertide07]

Its a 140 tune, on a stock auto tranny.

No, no, no...I recommend taking that chip off (unless you can resist the urge to put it on 140) before you tear that transmission up. I would not go over 75-80 on a stock transmission IMO.

[cleatus12r]

What is your invoice number?

[tpearia]

Invoice number 3833.

Only reason I had the 140 on it was just to check it out. Not something Ill use on a regular basis. Its a hauler not a hotrod. lol

Seems to do it with any tune really. Been driving with the fuel sipper tune, and it just seems whenever it shifts, not sure how to describe it, maybe locks the converter up immediatly? It goes into the next gear ok, for a second, and then the rpms drop way down, in somewhat of a jerk, almost bogging the truck. Does it under normal and moderate throttle.

[rammertide07]

Invoice number 3833.

Only reason I had the 140 on it was just to check it out. Not something Ill use on a regular basis. Its a hauler not a hotrod. lol

Seems to do it with any tune really. Been driving with the fuel sipper tune, and it just seems whenever it shifts, not sure how to describe it, maybe locks the converter up immediatly? It goes into the next gear ok, for a second, and then the rpms drop way down, in somewhat of a jerk, almost bogging the truck. Does it under normal and moderate throttle.


Sounds like the way your programming for your shift points were done.

According to my OHD, 140 is my fuel sipper. 80DD doesn't seem to do anything over stock except adjust shift points:shrug:

[cleatus12r]

You are using the most popular hex code we have for the FU, VRAA6S3 (PMT1). It is the same exact version of the program that every other PMT1 FU customer has access to. If there is something strange going on with the shifts, it would occur in every truck that is using the VRAA6S3 tunes with their FU. Is your transmission modified in any way? Sometimes shift kits will cause what you describe.

[tpearia]

Its a PMT2. No tranny mods that im aware of, doesnt feel like a shift kit.

It does have (slightly) different tire size on it from stock, which was given on the order form, if that makes any difference.

If I just knew that maybe the converter locking up sooner or something is causing what im feeling, thats fine. I have no issues with it as long as i know thats what its supposed to feel like.

Thanks!

[cleatus12r]

Your computer code may be PMT2, but the tuning on the chip is PMT1.

[tpearia]

Oh, ok, my apologies. Didnt know if that made a difference or not.

Thanks for your input!

[cleatus12r]

I suspect you're feeling the 2-3 shift and then an immediate torque converter clutch apply at certain accelerator pedal positions (happens when the 2-3 shift happens just above 35 MPH).