SunlitComet
OBS Jedi-Do Good
it's how i roll foo.
170K 4L60E Harsh 1-2 upshift.
- Thread starter 99Vortec
- Start date
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Jerky Arm Ape
Full Access Member
Well it doesn't matter, but I'd still like to know what might have not been right in the trans I had rebuilt?
I see servo swaps and such in other threads is there something external on the trans that will make it happen?
---------- Post added at 04:55 PM ---------- Previous post was at 04:52 PM ----------
Like the tsb you mentioned early on what is that for sunlit?
Hope you don't mind the brain pick...
I like to house as much knowledge as I can so when I have an unusual problem with mine in the future, I have a few things to check.
I see servo swaps and such in other threads is there something external on the trans that will make it happen?
---------- Post added at 04:55 PM ---------- Previous post was at 04:52 PM ----------
Like the tsb you mentioned early on what is that for sunlit?
Hope you don't mind the brain pick...
I like to house as much knowledge as I can so when I have an unusual problem with mine in the future, I have a few things to check.
SunlitComet
OBS Jedi-Do Good
tsb for valve body rework and/or replacement along with separator plate. not external work but just inside the fluid pan.
Trans ended up giving up. I got a hard shift between first and second, then a slip. Lost second gear and reverse on way to work. 
Had it rebuilt. Torque converter was blue, sunshell and input planetary hub were damaged I believe.
Also had the transfer case "Pump rub" kit put in.
Gotta make a trip out to Napa County tomorrow. Will see how it goes...
Had it rebuilt. Torque converter was blue, sunshell and input planetary hub were damaged I believe.
Also had the transfer case "Pump rub" kit put in.
Gotta make a trip out to Napa County tomorrow. Will see how it goes...
xanatost
Full Access Member
The sun shell has always been a big problem with these transmissions. Chevy used crap steal to make them and the one in my hoe went out i think around 55,000 miles. I rebuilt mine and I do fluids once a year just because I do off roading.
SunlitComet
OBS Jedi-Do Good
Trans ended up giving up. I got a hard shift between first and second, then a slip. Lost second gear and reverse on way to work.
Had it rebuilt. Torque converter was blue, sunshell and input planetary hub were damaged I believe.
Also had the transfer case "Pump rub" kit put in.
Gotta make a trip out to Napa County tomorrow. Will see how it goes...
sounds like the lubrication got restricted and some parts got overheated.
300 Miles into rebuilt transmission now. Just threw a P1870 code at me.
Hard 1-2 shift right after extended highway driving.
I see this TSB #01-07-30-023A as a GM Issue as the condition was originally reported to be occurring in as little as 20K miles.
Although, I am surprised that the re-builder did not address it. But then again, I did not specifically ask for a valve body upgrade at the time of the rebuild. (Just added on the tcase saver.)
Guess I need to be MORE specific!
The valve body upgrade doesn't look too tricky. I'm gonna consult with the builder first and see if he is willing to cover it with or without my help$.
Technically though, a P1870 code will fail an emissions testing if it throws out on the dynamometer?
Hard 1-2 shift right after extended highway driving.
I see this TSB #01-07-30-023A as a GM Issue as the condition was originally reported to be occurring in as little as 20K miles.
Although, I am surprised that the re-builder did not address it. But then again, I did not specifically ask for a valve body upgrade at the time of the rebuild. (Just added on the tcase saver.)
Guess I need to be MORE specific!
The valve body upgrade doesn't look too tricky. I'm gonna consult with the builder first and see if he is willing to cover it with or without my help$.
Technically though, a P1870 code will fail an emissions testing if it throws out on the dynamometer?
SunlitComet
OBS Jedi-Do Good
yep because it effects mileage and therefore emissions.
So the SES light set last Friday with the P1870 code. Last Sunday I swapped out the Throttle Position Sensor on a whim. And then Monday morning, the SES light shut itself off without me having to clear the code. (I was driving and saw it switch off.)
I wasn't aware that a B type code could clear itself?
So far it hasn't hard 1-2 shifted yet. Though, I Haven't had to do a 70MPH run for miles since then either.
"DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).
When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL)."
I wasn't aware that a B type code could clear itself?
So far it hasn't hard 1-2 shifted yet. Though, I Haven't had to do a 70MPH run for miles since then either.
"DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).
When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL)."
SunlitComet
OBS Jedi-Do Good
it can clear itself by four means. scanner reset, 3 consecutive trips with out the error. error no longer exists and pcm shut down by key off. your fluid level is correct right? when it get low it can do that because you suck in air not to mention the temp of the tranny climbs really high.
---------- Post added at 11:56 PM ---------- Previous post was at 11:50 PM ----------
the shop actually told me that someone attempted to install a shift kit but did not complete it. no further details on what parts were completed.
the tsb addressed the code p1870 issue that was resolved with a revised valve body assembly. involved just dropping the fluid pan. there was a valve bore that would wear out and leak thru to cause the issue.
---------- Post added at 11:56 PM ---------- Previous post was at 11:50 PM ----------
the shop actually told me that someone attempted to install a shift kit but did not complete it. no further details on what parts were completed.
the tsb addressed the code p1870 issue that was resolved with a revised valve body assembly. involved just dropping the fluid pan. there was a valve bore that would wear out and leak thru to cause the issue.
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