1870...maybe...

1870...maybe...

Postby TucsonRay [OP] » May 22nd 2014, 6:12pm

So interesting thing going on with my 03, not too worried about it yet. Check this out.

So for awhile now Ive been getting the hard 1-2 shifts. Ive done a lot of research and have read all about the TCC and such.
from what Ive read most folks experience the rough shift after extended highway miles or just when things get real hot.

My van does it always. pulling out of the driveway on a cold morning it will do it on the very first shift to second. However, it only does it when you accelerate slowly. the faster I push the pedal the smoother the shift. it shifts perfectly if I push it just a little harder than "normal" at a light or pulling out etc. Ive gotten in the habit of goosing it just a bit and now barely ever get the rough shift.

Soooo...last night I swapped the ATF and the gasket and filter and such. the oil was just a little dark, but no chipps in the pan, no chunks, overall an extremely sexy pan lol. I was relieved Ill tell you that much,

buttoned everything back up check the fluid and drove to O'Reilly to get my check engine soon light checked out.

First shift out of the driveway....I went slow on purpose to test....no harsh shift! yay. however the 3rd 1-2 shift I went extra slow and did feel a slight bump, but not nearly as bad as it had been before.




SO long story short, its waay better now but not completely fixed....so I don't really know whats going on

could it still be 1870? (no 1870 code thrown btw)
maybe just basic old transmission wear? (its got 120k very well maintained miles but who knows...)
:confused:

by the way every time I check my fluid level before the flush, it was always way high, I assumed I was doing it wrong, but after the refill, it was just under the high HOT mark (when hot) so maybe it was overfilled......'

sorry for the rambling all thoughts on the issue are appreciated!

and the code was a P0420, so Ive got that to deal with now lol, Ill put that in another thread

thanks!
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Re: 1870...maybe...

Postby 97cargocrawler » May 22nd 2014, 6:25pm

As the tranny wears out the lag time between gears increases. The PCM commands a higher shift pressure to keep those times within acceptable parameters. It's call TAP (transmission adaptive pressure). Mine did that for about a year before it imploded on the highway. My new tranny does it because I have a shift kit and it makes me paranoid as all hell because it's a constant reminder of the previous tranny.
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Re: 1870...maybe...

Postby gavio » May 22nd 2014, 6:43pm

I had some similar odd behavior in my 03 Astro that I had for a few months.... I took it to a tranny shop (a good one) and they used a professional code scanner to look in the transmission module at the history and it had been intermittently logging a code related to the pressure control solenoid and the shift solenoids... They replaced the solenoids to no avail, but eventually found a broken wire going to the PCS... fixed that and the tranny was like butter again... That van had over 200k miles on it....

The scanner they use at parts stores doesn't access the tranny module and it doesn't access the history - those were the keys....

Something to consider.
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Re: 1870...maybe...

Postby TucsonRay [OP] » May 22nd 2014, 8:25pm

97cargocrawler wrote:As the tranny wears out the lag time between gears increases. The PCM commands a higher shift pressure to keep those times within acceptable parameters. It's call TAP (transmission adaptive pressure). Mine did that for about a year before it imploded on the highway. My new tranny does it because I have a shift kit and it makes me paranoid as all hell because it's a constant reminder of the previous tranny.



that sucks!! hopefully your new one lasts!

that scares me a bit not gonna lie...but its a good place to start

gavio wrote:I had some similar odd behavior in my 03 Astro that I had for a few months.... I took it to a tranny shop (a good one) and they used a professional code scanner to look in the transmission module at the history and it had been intermittently logging a code related to the pressure control solenoid and the shift solenoids... They replaced the solenoids to no avail, but eventually found a broken wire going to the PCS... fixed that and the tranny was like butter again... That van had over 200k miles on it....

The scanner they use at parts stores doesn't access the tranny module and it doesn't access the history - those were the keys....

Something to consider.


thanks excellent info!
a buddy of a buddy (buddyamine lol) runs a transmission shop, its probably time to stop putting it off and have him check it out.
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