Lockup issues?

[Yngwytprik]

I was just reading-up on that kit and it seems to be associated with at least two symptoms, i.e.,

- hard 1-2 shift at part throttle
- TCC lockup abnormalities

Do you have other problems besides the lockup "dithering" you mentioned?

No 9 times out of 10 it shifts smooth as butter although ive noticed here and there it will shift kinda hard out of 1st but its pretty rare. Also if i put the shifter in “3” it will shift 1st-4th and not use lockup at all. Thats what ive been doing once i hit the backroads where i live. Out here in the middle of oklahoma theres plenty of long 45mph roads and its alot nicer cruising them around 1900-2000 rpm than it is with lockup kicking in and out the whole stretch. 10 miles of them flowmasters growling up and down over and over and over steady cruising 45 mph gets pretty old lol

 

[1998_K1500_Sub]

No 9 times out of 10 it shifts smooth as butter although ive noticed here and there it will shift kinda hard out of 1st but its pretty rare.

OK, that's encouraging.

Also if i put the shifter in “3” it will shift 1st-4th and not use lockup at all.

In "3" it should shift 1-2-3 and then lockup the TCC in 3rd when conditions are met. TCC lockup isn't as noticeable in 3rd because the converter tends to slip less (higher converter RPM combined with less applied torque results in less converter slippage).

You might consider leaving that TCC kit on the shelf for a while, or longer, if the lockup symptom disappears when you replace the TPS. I'm thinking "if it ain't broke..."

10 miles of them flowmasters growling up and down over and over and over steady cruising 45 mph gets pretty old lol

I know what you mean, that's why I ditched the Flowmasters and installed Dynomax UltraFlows

 

[Yngwytprik]

OK, that's encouraging.



In "3" it should shift 1-2-3 and then lockup the TCC when conditions are met. TCC lockup isn't as noticeable in 3rd because the converter tends to slip less (higher converter RPM combined with less applied torque results in less converter slippage).

You might consider leaving that TCC kit on the shelf for a while, or longer, if the lockup symptom disappears when you replace the TPS. I'm thinking "if it ain't broke..."


I know what you mean, that's why I ditched the Flowmasters and installed the Dynomax UltraFlows

Hmm, so in 3rd it gets into lockup and doesnt have an issue staying in at the typical speeds 4th cant hold lockup. Weird. At least when i get goin 60+ in 4th it holds lockup perfectly fine. Uphill and all.

 

[1998_K1500_Sub]

Hmm, so in 3rd it gets into lockup and doesnt have an issue staying in at the typical speeds 4th cant hold lockup. Weird. At least when i get goin 60+ in 4th it holds lockup perfectly fine. Uphill and all.

Interesting... likely because the throttle position is different in 3rd vs 4th, at the same speed.

Replace that TPS

 

[JWOK]

No 9 times out of 10 it shifts smooth as butter although ive noticed here and there it will shift kinda hard out of 1st but its pretty rare. Also if i put the shifter in “3” it will shift 1st-4th and not use lockup at all. Thats what ive been doing once i hit the backroads where i live. Out here in the middle of oklahoma theres plenty of long 45mph roads and its alot nicer cruising them around 1900-2000 rpm than it is with lockup kicking in and out the whole stretch. 10 miles of them flowmasters growling up and down over and over and over steady cruising 45 mph gets pretty old lol

Just thought I would give you a little more info on my last experience with the TCC regulator/isolator issue. My own Yukon began the TCC cycling around 45-50 mph and that was the only noticeable symptom initially. When it was driven on longer trips towing a trailer it would start the hard 1-2 shift and set the 1870 code, but this would stop after the trans cooled down. This eventually progressed to the point that hard 1-2 shifts and code 1870 resulted from long trips without the trailer which finally prompted me to repair the worn valve bore.

I have no intention of steering you away from other repairs you are implementing. I only wanted to give you a little detail from my own experience where the symptoms may not exhibit exactly as they would seem to be outlined by a TSB or other fault description.

 

[Yngwytprik]

Snow storm put a delay in shipping on my parts. Still waiting…

 

[Yngwytprik]

Tps made no difference. I also ran the codes again and this time the tps code wasnt there? Who knows.
If i can find the time this weekend ill try to throw the tcc valve “upgrade” in and see if that fixes it.

 

[Yngwytprik]

Noticed today a whine i believe is coming from the trans. Only seems to whine in forward gears. No whine at all with any rpm in park and neutral. Almost sounds like a power steering pump whine but like i said only in gear with acceleration. In gear foot on brake at a stop no whine… im getting the vibe the trans is counting its last miles down. Still pulls hard, no slips, all gears are there no extra 4l60 neutrals. Yet. Guess ill start looking around to have a trans on standby.

 

[stutaeng]

If is truly coming from the transmission, then it's most likely not a good sign. Whine is usually from the pump (sometimes from not seating the converter correctly.)

I didn't read all 4 pages, but I didn't see if you have dropped the pan to see what it looked like?

 

[Yngwytprik]

It is truly coming from the transmission, then it's most likely not a good sign. Whine is usually from the pump (sometimes from not seating the converter correctly.)

I didn't read all 4 pages, but I didn't see if you have dropped the pan to see what it looked like?

Not yet but hopefully this weekend i can get to it.