Hi everyone!
Got a 1997 GMC Savana 1500 with L31/4L60E approaching 150K miles. At one point last summer (the rig is mainly used as a vacation-vehicle for me and the family) when driving home from our holiday, the gearbox started to shift really hard between 1-2 and I lost the lockup. This was after a few hours of driving on a hot day with the van fully loaded. We pulled over, read the codes and it was the infamous P1870. After like an hour, we took off again and the code and hard shifts were all gone and lockup had returned as well. Managed to drive another 3 hours without any further hassle and it has not returned since then, though it has not been driven any long distances either.
So, I´ve read both on this forum and elsewere that this is more or less typical for the 4L60E and that the cure is to install some sort of PWM delete/block off valve instead of the OEM version.
If I were to buy a Fitzall valve like the one suggested in the very informative thread by @NickTransmissions, is it possible to install this without removing the valve body ? I´ve seen some clip on youtube saying it is possible with a bit of fiddling, but what do you guys on this forum say? The reason I´m asking is that I´m fairly experienced with mechanical work but have only done fluid and filter changes as far as transmissions are concerned, so I´m not sure whether i would be able to pull it off if the valve body has to come out.
Aside from changing the valve, is there anything else you think be worth replacing "while in there"? The transmissions shifts fine in my opinion and the oil seems to have normal red color without any funky stuff on the dipstick.
Are there any negative aspects of deleting the PWM as far as transmission durability goes? I´ve read on Sonnax´s website that it puts stress on different transmission components and that they recommend to use their solution, but it requires more tools and, not to say the least, more money.
Sorry for all the questions, but like I wrote, this is a bit uncharted territory for me and there aren´t many US transmission specialists close to where I live (middle part of Sweden). Any help or advice would be appreciated.
Thank you!
//J
Got a 1997 GMC Savana 1500 with L31/4L60E approaching 150K miles. At one point last summer (the rig is mainly used as a vacation-vehicle for me and the family) when driving home from our holiday, the gearbox started to shift really hard between 1-2 and I lost the lockup. This was after a few hours of driving on a hot day with the van fully loaded. We pulled over, read the codes and it was the infamous P1870. After like an hour, we took off again and the code and hard shifts were all gone and lockup had returned as well. Managed to drive another 3 hours without any further hassle and it has not returned since then, though it has not been driven any long distances either.
So, I´ve read both on this forum and elsewere that this is more or less typical for the 4L60E and that the cure is to install some sort of PWM delete/block off valve instead of the OEM version.
If I were to buy a Fitzall valve like the one suggested in the very informative thread by @NickTransmissions, is it possible to install this without removing the valve body ? I´ve seen some clip on youtube saying it is possible with a bit of fiddling, but what do you guys on this forum say? The reason I´m asking is that I´m fairly experienced with mechanical work but have only done fluid and filter changes as far as transmissions are concerned, so I´m not sure whether i would be able to pull it off if the valve body has to come out.
Aside from changing the valve, is there anything else you think be worth replacing "while in there"? The transmissions shifts fine in my opinion and the oil seems to have normal red color without any funky stuff on the dipstick.
Are there any negative aspects of deleting the PWM as far as transmission durability goes? I´ve read on Sonnax´s website that it puts stress on different transmission components and that they recommend to use their solution, but it requires more tools and, not to say the least, more money.
Sorry for all the questions, but like I wrote, this is a bit uncharted territory for me and there aren´t many US transmission specialists close to where I live (middle part of Sweden). Any help or advice would be appreciated.
Thank you!
//J