Rough Shifting Chevy

I apologize for posting a car question in a truck forum, But I couldn't find a Chevy forum here to ask my question.
I have a 2001 auto-trans Impala that normally shifts as smooth as silk.
Occasionally though after driving awhile it will begin to shift really hard and rough through all of the gears. After it sits overnight or for awhile it will go back to shifting smooth again as if there is no problem at all.
The problem isn't too frequent.. but I was hoping that somebody could steer me in the right direction what might be wrong so I will know what I am up against here.
Thanks for any help.. It is much appreciated!
Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 16 Nov 2007 01:39:45 -0500, snipped-for-privacy@webtv.net (Toad Monster) wrote:

First thing to do is have it scanned for codes. Some codes will cause the tranny to raise the line pressure to max when they set. This increase in pressure will often be felt as hard shifts. -- Old Crow "Yol Bolson!" '82 FLTC-P "Miss Pearl" '95 YJ Rio Grande BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Nov 15, 11:39 pm, snipped-for-privacy@webtv.net (Toad Monster) wrote:

Though I can't specifically answer about your car, I can tell you that Chevy's 4L60E trans has this same problem due to a design flaw with the valve body. Transgo makes a rebuild/shift kit that fixes this problem, if it is caught in time. One of the check ball seats gets worn to the point it becomes slightly larger then the ball, allowing it to sit in the hole and not come out. The kit replaces this with a larger ball and addresses other issues.
Depending on the tranny in your Imp, you may have a similar problem. Hope this helps a little bit.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@webtv.net says...

This is probably related to the Pressure Control valve. Either its sticking or the computer is detecting slippage. Sometimes cold weather causes these valves to stick if they sit a little while.
Here's a possible related TSB: _____________________________________________________ Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace Pressure Control Solenoid Valve Assembly) #00-07-30-002B - (07/19/2002)
2000-2002 Chevrolet Impala
Cause
The above condition may be due to any one of the following which may affect line pressure output:
* Sediment inside the pressure control (PC) solenoid valve, causing the PC solenoid valve to mechanically bind.
* Sediment in the valve body, causing the torque signal regulator valve to stick.
* Incorrect transaxle oil level. _____________________________________________________
(Now watch out for Snoman. If he see's your thread he might confuse your 4l65e with a Powerglide.)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@wah00.com says...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

So, it sounds like the 4t65e and the 4l60e have the same problem
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Basically:
That's why they went to the 4L65 and the 4T65 due to some mediocre upgrades.
RK
says...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

So, will a 4L65E bolt in place of a 4L60E? Would it even be worth the swap?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I'm sure it will:
The updates are electrical, and the two issues in the valve body. But, the 4L65E fits the LS series small blocks, I don't know if they have the same bolt pattern, or a dual bolt pattern.
I've yet to rebuild a 4L65E, but the valve bodies are visually different.
RK PS I don't know if the electronics are the same impedance either, but that can be worked out any way.
says...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hmm, maybe I should ask the tranny expert of 1870, Snofraud and see what he has to say about this? LOL
Thanks for the info though, I'll keep that in mind if I keep the Silvy much longer then I plan too. Right now, it hard shifts a little, but I know the transgo kit will correct the problem and that is something that I can install myself.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I highly recommend the Trans-Go kit,
I especially recommend you install it yourself also. You'll take the time to look at the filings and see if there is more clutch than steel, iron and brass than any tranny shop would.
RK
says...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I was going to post on the pressure control solenoid:
Just to add on your post, these solenoid valves have the tendency for the coil to break down: (wear and short internally) under the higher temperatures that are generated by the slippage.
So I would use a scanner and look at the rpm and output shaft speed in third gear. This is how the leakage and non operation is found.
RK
says...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.