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hey king nice write up very informative. i have a question for you. the stock fluid is dexron III is it safe to mix III and VI? i was told that was a no no. my fluid is a slight pink color at 121xxx miles. idk if the filter has been changed or if any other transmission maintenance was been done. my car was a cop car out of chicago until i bough it at 88xxx miles. 2003 3.8. what do you think?
Use dexron 4 by itself. It is the better fluid.
 

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For 2002 - 2011 transmissions I found a TSB that may help prevent or fix some of the harsh shifts/late shifts or even the intermittent neutral at stop lights that these transmissions develop. It's TSB#08-07-30-040C. It states that "A new transmission oil pan magnet, P/N 29535617, was released for service. The current square transmission oil pan magnet may become saturated with normal ferrous sediment and the Pressure Control Solenoid (PCS) is now collecting ferrous sediment, making it vary from design. For a given current the PCS electromagnet is stronger, causing the line pressure to be less than needed." So at your next transmission service it may be a good idea to upgrade the current magnet with the two new magnets (one placed in the current magnets location and one on the oil filter). Their is a post on another forum that has good pictures of where to place the magnets. 4T65E-HD Delayed engagement fix - LS1TECH
 

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Thanks for that thread and the TSB #. Very helpful. :eek:k3:

I'm coming up on the fluid service later this spring... Prolly more like summer as it doesn't look like we will get much spring this year.

Rocco360. They never made a Dexron IV (4). This is a pretty good explanation that's still on the wayback machine. DEXRON®-VI - GM Techlink
I think some folks get confused by Roman Numerals...

One I
02 II
03 III
04 IV
05 V
06 VI
07 VII
08 VIII
09 IX
10 X
11 XI
12 XII
13 XIII
14 XIV
15 XV
16 XVI
17 XVII
18 XVIII
19 XIX
20 XX
50 L
100 C
500 D
1000 M
That's all I can remember off the top of my head.
I was 4th grade in MCMLXXVII and it's MMXIV now. :devil:
 

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Bout my 2010 impala at 63k, looked like it was a rental car because of the oil stickers I found in it. The atf fluid was brown but did not smell burnt had it flushed at work for free and it seems ok still, when should I change the filter?
 

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Bout my 2010 impala at 63k, looked like it was a rental car because of the oil stickers I found in it. The atf fluid was brown but did not smell burnt had it flushed at work for free and it seems ok still, when should I change the filter?
GM says change tranny fluid at 50K miles for severe duty. Fleet use qualifies as severe.
I'd swap the filter with an AC Delco or Wix unit. I'd also install a Dorman drain plug pan with the new magnets from the TSB. The drain plug lets you pull the pan, next time, without wearing a gallon of Dexron VI or pouring it all over the floor. I'll be punching a hole in my old pan.
 

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Did 2010s even have filters? I thought GM went to screens on these things back in the early 2000s. The screens don't get changed but rather were designed to be cleaned via a transmission flush process from what I have been told by several tranny techs and GM Techs.
 

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my 04 has a filter.. the exact one shown..
 

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Mr. Handy
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The filter is actually a screen. Was told this by valvoline service anyways.

I have been experiencing hard shifts when fluid gets warm ever sincey Trans flush however. Likely due to crap being removed from the accumulators.

The fluid was black :-( when it got flushed out. Thinking of dropping the pan, doing a Trans go shift kit, adding a magnet, and replacing fluid.
 

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NO filter screens in ANY GM transmission for the primary filter, the OEM filter is a high quality filter. Some aftermarket filters may just be a screen. Now on the 6 speeds their is a secondary filter screen behind the TEHCM (pronounced "TECH-im") / Transmission Electronic Hydraulic Control Module to protect the solenoids from any debris that may escape the main filter or get created after the filter.
 

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The filter is actually a screen. Was told this by valvoline service anyways.

I have been experiencing hard shifts when fluid gets warm ever sincey Trans flush however. Likely due to crap being removed from the accumulators.

The fluid was black :-( when it got flushed out. Thinking of dropping the pan, doing a Trans go shift kit, adding a magnet, and replacing fluid.
That's what I did and it works great.
 

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Mr. Handy
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Did you have hard shifts before like I am experiencing? It's only once the fluid has warmed up and usually takes a 30min drive or so.
 

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Did you have hard shifts before like I am experiencing? It's only once the fluid has warmed up and usually takes a 30min drive or so.
Exactly.. after operating temp if the shifts are longer than the computer is expecting(which is like .65 seconds for a complete shift) 3 times in a drive cycle.. The computer commands max line pressure(max adapt). That's what causes the harsh shifting.. The kit optimizes the shift points by making the accumulator piston spring faster at my best guess.. My symptoms were precisely the same as yours..
 

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To add to that if I pulled over and turned the car off waited a few seconds with the key out, Then turned it back on I'd either get no harsh shifts for another 30 minutes or so or I'd at least get a few minutes of long but, not harsh shifts..
 

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One more thing.. It's imperative for whatever reason to scuff the shit out the walls in the accumulator where the pistons are with an emery cloth or whatever abrasive material you have.. I believe I used sand paper and ensured no residue remained.
 

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Mr. Handy
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Ya I did some reading on the transgo installation procedure and found that scuffing was necessary. Did your hard shifting throw a code and check engine light or?

Looks like I'll be doing this sometime this summer when funds allow me to do so
 

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Also .. What did u use to clean the accumulators after sanding them? What grit paper? Any idea?

I wonder if a tuned PCM from overkill with the increased line pressure would fix this hard shift problem?
 

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Also .. What did u use to clean the accumulators after sanding them? What grit paper? Any idea?

I wonder if a tuned PCM from overkill with the increased line pressure would fix this hard shift problem?
the kit is cheaper but the pcm has other benefits.. as far cleaning it out.. brake cleaner and lint free cloth is what I used on everything including the pan..
 

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DallaSS 214
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could my tranny be going out?

I replaced the tranny filter, and replaced the oil

Now, when stopped at a red light, then green, I press on the gas, and it feels like the engine revs up, there's like a 1-1.5 second LAG where it just stays there, all of a sudden a JOLT and the car goes

I plan on getting an overkill tune but if that won't help, what do i do from here?
 

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could my tranny be going out?

I replaced the tranny filter, and replaced the oil

Now, when stopped at a red light, then green, I press on the gas, and it feels like the engine revs up, there's like a 1-1.5 second LAG where it just stays there, all of a sudden a JOLT and the car goes

I plan on getting an overkill tune but if that won't help, what do i do from here?
Have you checked the fluid level and what type of fluid did you use?
 
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