Tig

My tranny has been shuddering/vibrating at around or over 40 mph.
It only does it when I'm at a steady speed. If I'm under load/accelerating it's fine, its when I cruise at the same speed is when it happens.

Can someone help me diagnose this problem?

I have been told it could be the converter or the vb or both.

Its for an 07 Tahoe 2wd w/5.3.
Thanks

Someone had posted this on another forum = " It sounds like this is happening when TC lockup would occur, which is only when speeds exceed 43-45MPH and is kept at that speed, or higher, for an extended period of time.

So I would scan the ECM for possible codes concerning the transmission ASAP."

mrvedit

The post from the other forum sounds very likely.
Usually the TCC PWM valve doesn't wear out within 6 years, but perhaps it has.
If you have tuning software, it might help to tune the TCC Duty Cycle for both minimum and maximum to 100%.
Otherwise replacing the TCC PWM valve with the Fitzall valve or equivalent valve from the Transgo HD2 or Sonnax Performance Pack shift kits is more likely to fix it.

Tig

Thanks for the reply, I appreciate it.

I'll have to make an appointment for it to get tuned.
Does torque management need to be removed? I'm sorry I'm not a transmission guy at all.
Do they sell valve bodies already modified? If so do you know of a reputable company that has them?

Thanks again, I appreciate it.

Tig

I made an appointment. They were using HPTuners, nothing came up on the scanner. I guess if no codes have been thrown, they cant see anything.

He couldn't feel the shudder/vibration when he went out so, he asked me to go along for a ride. We went for a cruise so I could point out what was going on. I pointed it out and he finally noticed it. What he did notice was the converter was not locking or unlocking when driving at speeds and pressing the brakes. He asked how my MPGs were, I responded "terrible", he said "that's why".

Basically, long story short. I ordered a new converter, larger cooler, shift kit and he is going to tune it for me (engine and trans).

^^^^
That was last week. I picked it up Saturday and not only did it not resolve the issue, it is more pronounced and now it happens around 35mph. Not only does it shudder at 35 but it sounds like metal is rattling and then it clunks.

I don't know what he did with the tune either, he changed the shift points and I don't think I'm too thrilled with it. I think I would've liked it the way it was.

NewOrleansLT1

Bump up your lock up from 35 to maybe 45 or 50mph.. Having the converter lock that low is bogging your engine..

Tig

Is that what is causing the shudder and rattling at 35mph?
Is that something that could be done through HPTuners?
What about at higher speeds?

I'm getting confused because I am hearing it could be the converter or it could be a miss fire

Thanks

jimmyblue

iTrader: (11)

If it's a lockup clutch, pressure / PWM type problem
I think you're going to notice it more as a groan or
howl. If it's bucking, this might be more about bad
state-of-tune against a hard coupled driveline. With
a scan tool you could determine whether there is
slip attending or causing the "shudder".

My setup is happy lugging at 1500RPM locked, although
at higher pedal I set it (TCC) free. But I spent a lot
of time getting things how I like.

NewOrleansLT1

My car kinda did the same thing. I bumped up the lockup to 50mph/2000rpm in 4th gear

Tig

Its definitely a shudder/vibration What I do notice is when under acceleration its fine.
I don't think they properly tuned it either. They never hooked it up while driving to determine where the problem was actually coming from.

What I find odd is, it did it before and now its doing it again. After everything has been done, including the tune.
I'm stumped. I'm kind of hesitant to bring it back to them.

I took it out once yesterday and just came in from running to the store. If I am on the gas (not WOT), its fine at lower speeds. No shudder at that sweet spot (30/35mph). Its when I'm cruising, it shakes like a friggin earth quake, especially around 30/35 and it sounds like metal is vibrating.

Tig

I'm sorry, I was wrong. After speaking (through PMs) I had gotten in touch with one of the guys I'm dealing with.
He said he had the scanner hooked up when the mechanic took it out.
I am at a loss for words I'm so disgusted.

mrvedit

Do you know what your cam duration is?
Jimmyblue says he can cruise at 1500 rpm locked with his 224/224 cam.
However I have a 231/239 and I would get all kinds of lugging/shaking if I locked at 1500 rpm. Therefore I set my lockup speed (3.42 rear) at 52 mph.

It is sounding more like a tuning problem than a trans problem. Find another tuner or consider a mail order tune from e.g. Frost.

jimmyblue

iTrader: (11)

I specifically went with the wide separation cam to
avoid extra effort in tuning / drivability issues on the
street for the way I drive (low & slow with exceptions,
but exceptions must satisfy).

It'd be unreasonable to expect the same with more
duration and less separation, and the shiftpoints and
lockpoints want to be adapted to the reality of the
final motor tune and how you want to drive - though
these themselves may not be all that consistent if a
track-oriented set of choices is applied to a daily
driven vehicle.

Tig

mrvedit,
As far as I know, its a stock 5.3 cam. I'm not sure if the PPV models have different cams, from my understanding they get a tune and gears. Everything else is factory. Though I did notice they have 243 heads. I was not aware of Tahoes coming with 243 heads.
I have 4.10s out back.

Sorry for my ignorance but, how do you do a mail order tune?

jimmyblue,
From the way you describe you driving, we have something in common.
Who did your tune? How did you figure out what you wanted.
This is a very weak point for me, I know nothing about tuning/transmissions.

What do you do with the previous tunes? I liked how the tune was before the parts were installed. I'm hesitant to go back but I'm not sure how I'm going to get it back the way it was without going there to hook it back up to HPTuners.

A little update.
After a long day of rain, I started to change the plugs and wires. All of the old plugs were gapped from .47 to .50. New plugs AC Delco 41-110 were gapped to .45.
The plugs came apart on 1 and 7. I cant reach the passenger rear. It started getting dark and I couldn't see to finish. Is there a trick to removing that passenger rear plug?
Seriously, I'm not sure how to get to it with my mitts.


Thanks guys, I appreciate your help and info

Whats up with the forum?

mrvedit

OK, I guess we got off-track with the cam thing.
If you have a stock cam, you should be able to run a stock tune (other than a few mods for your stall converter) and the TCC should lockup properly at around 35mph and run smoothly.

Obviously you need to get the new spark plugs and wires installed and see how things run.

If the shuddering continues, then unless you get better advice, I would suggest replacing the TCC valve in the valve body with on on/off valve, e.g. the Fitzall. Most (all?) aftermarket converters prefer an on/off valve anyway.

You still need to get a tune for the high stall converter. Mostly to reduce the WOT shift MPH, disable the misfire tables and disable a few other codes.
jimmyblue is a wizard tuner and obviously does his own. The tuning section has sponsors that provide mail-order tunes; I think "Frost" is one.

I cannot help you with the spark plug problem as I don't have a Gen 4 (partly due to difficult engine access). I always put dielectric grease on the spark plug connectors as it also acts as a lube. Then to remove a wire, I turn the boot a bit and it slides off easily.

01dropTOP

iTrader: (3)

I have the same shudder issue with mine right now too. Mine isnt tuned yet, so hopefully it goes away with that.

As far as the #8 plug, jack up the passenger side and you can access it easily from below. Hope that helps

Roarin_8

iTrader: (5)

Yes they have 243 heads, I got my 243s from a Tahoe.

Tig

mrvedit,

What mods are necessary for a new stall? In my 99 Tahoe, I had a built tranny and a Yank 3200 billet converter and I did not have a tune and it ran like a champ. Does it depends on the year?

Swapped plugs n wires and it still happens, awesome. I also put dielectric grease on them.

Is the TCC valve included in a Transgo shift kit Jr? That was also installed when I got the work done.


I wish I new more about all this tuning stuff, its like Chinese to me.


01droptop,
I hope a tune straightens yours out. I'm hoping to find out soon.
As for the rear plug, you got it. Going from under the truck certainly helped. I also used a pair of needle nose pliers to pop the plug wire off by the metal boot protector.
A 1" ratchet extension also made it worlds easier.

Roarin 8
Thanks, I had no idea. But, am pleasantly surprised

Thanks again for the help fellas, I hope everyone enjoyed there holidays and have a safe and happy new year.

Tig

I broke down and brought it to a local dealer.
I took it for a ride with the tech, fortunately he felt and heard everything.
They scanned it and it seems the converter is the issue.

I'm going to wait until Monday to hear back from the shop for there results before I jump to conclusions.
They will get me a new converter if need be.

mrvedit

What converter are you going to get - I'm sure you don't want a stock one.
(Sorry I didn't answer your question - Yes the TCC valve is part of the HD2 kit, assuming it was installed.)

Tig

This is the one I got, I'll probably get the same one in return. It would be a warranty issue so, this is the least expensive way around forking out another $750+.
http://shop.fticonverters.com/LS-SER...L-SRLS3082.htm

That's cool, I'm hoping they did.

thanks again