Stoffregen Motorsports
Explorer
Finally, some great news.
After spending a week at Jim Miller's Zero Gravity shop in Arizona, the project has finally come to an end. He was able to work his transmission tuning magic to bring it up to snuff, while also adding in some tuning goodies. With the flexibility of the tuning on this trans, the shift modes can be individually tuned or programmed with unique characteristics. So park, reverse, neutral and drive retain their normal functions, but he was able to program the 2nd gear slot with a sport mode. No "tow/haul" button needed. Just drop from D into 2 and you're now in sport mode. Pretty cool.
Lots of small details extended the duration of the project, but I would say about 99.5% of the entire vehicle's systems have been gone through and modernized. Let's take a look back at the journey.
We started this project about this time last year, and quickly realized that the 6L80E trans we bought was actually a 6L90E. Not being compatible with the Advance Adapters split case adapter, we had to source another trans. A call was made to Pacific Fab to rectify the situation. After the new trans was installed, it was known that the new trans computer would have to be re-flashed with the body computer connected to it. So we loaded it on the trailer and took it to Motor Machine in Sacramento for our re-flash.
During the re-flash and tune session, we realized that the trans computer was not compatible with the ECM, so another call to Pacific Fab had a new ECm on the way. That computer was then installed and back to Sac we went. It all seemed to be working fine on the trailer, but when I got it back to the shop and off the trailer, I soon found that none of the gears worked as they should. It would go into reverse and drive, but it would drop out of gear at times.
After another call to Pacific Fab the decision was made to bring the truck to their shop in Gilroy, so back on the trailer it went and two weeks before Christmas, I made the 3.5 hour journey south. We figured that something was getting lost in translation and the best way to handle the situation would be to have them go through it wire by wire. All appeared to be going well, but then I was told that the transmission was no good, and that it was my fault. Not wanting to get into an argument, I owned the situation and had the truck brought back home.
The trans was pulled and brought to my transmission shop in Olivehurst where Ed Okray went through it to give it a clean bill of health. This was touch and go. Because of the nature of the clutch design in the 6L80E, they don't hold up well when the clutches start to slip. We didn't even know if it would be repairable. It was and I picked it up a week later. While I was there, we discussed possible causes of the failure and we found that the transmission had undergone previous repairs that were not done properly, exonerating me from causing the trans to fail. We also decided that a larger cooler would be a good idea. A low pressure drop cooler was sourced from Ed. At this point I wish he had opted to install a new pump, for reasons you will soon find out.
Ed had his toque converter service build us a custom, billet faced converter and that was installed here with the rebuilt trans, as well as the new, larger cooler. Installing the larger cooler meant completely re-doing the brackets and lines to get it to fit in behind the grill alongside the power steering cooler.
Two days later I had the trans back in and hooked up to my laptop. Some tuning is required after a rebuild, so the engine was fired up and brought up to temp. The tuning requires that the trans is up to temp.
Excited as all hell, I hopped in the truck and drove it around the neighborhood to find that the same symptoms reappeared. At this point I was utterly deflated. I picked up the phone and called the owner to give him the bad news. A day later the truck was on a transport to Arizona.
Jim Miller runs the Betty Ford clinic for GM electronic automatics (it's actually called Zero Gravity). His resume is extensive including actual design of a handful of GM automatic transmissions so we had faith that if there was anyone on the planet that could help us, it was Jim.
This week brought us great news, that after only five days in his shop, the truck was done and ready to go back home to Texas. During the process, Jim discovered that the pump in the trans was bad (ughh), so it was replaced and that was that...sort of. Not leaving well enough alone, Jim decided to kick it up a notch by adding the shift functions mentioned above.
Upon reflection, it was a very convoluted process. Many hands were involved and that only added to the confusion, but at the end of the day, it should be very fun to drive.
Thanks to everyone who offered advice or support during the process and thanks for watching. I am closing out the build with a handful of pics, but I hope that the vehicle's owner will update the thread as he sees fit and as time goes on.
After spending a week at Jim Miller's Zero Gravity shop in Arizona, the project has finally come to an end. He was able to work his transmission tuning magic to bring it up to snuff, while also adding in some tuning goodies. With the flexibility of the tuning on this trans, the shift modes can be individually tuned or programmed with unique characteristics. So park, reverse, neutral and drive retain their normal functions, but he was able to program the 2nd gear slot with a sport mode. No "tow/haul" button needed. Just drop from D into 2 and you're now in sport mode. Pretty cool.
Lots of small details extended the duration of the project, but I would say about 99.5% of the entire vehicle's systems have been gone through and modernized. Let's take a look back at the journey.
We started this project about this time last year, and quickly realized that the 6L80E trans we bought was actually a 6L90E. Not being compatible with the Advance Adapters split case adapter, we had to source another trans. A call was made to Pacific Fab to rectify the situation. After the new trans was installed, it was known that the new trans computer would have to be re-flashed with the body computer connected to it. So we loaded it on the trailer and took it to Motor Machine in Sacramento for our re-flash.
During the re-flash and tune session, we realized that the trans computer was not compatible with the ECM, so another call to Pacific Fab had a new ECm on the way. That computer was then installed and back to Sac we went. It all seemed to be working fine on the trailer, but when I got it back to the shop and off the trailer, I soon found that none of the gears worked as they should. It would go into reverse and drive, but it would drop out of gear at times.
After another call to Pacific Fab the decision was made to bring the truck to their shop in Gilroy, so back on the trailer it went and two weeks before Christmas, I made the 3.5 hour journey south. We figured that something was getting lost in translation and the best way to handle the situation would be to have them go through it wire by wire. All appeared to be going well, but then I was told that the transmission was no good, and that it was my fault. Not wanting to get into an argument, I owned the situation and had the truck brought back home.
The trans was pulled and brought to my transmission shop in Olivehurst where Ed Okray went through it to give it a clean bill of health. This was touch and go. Because of the nature of the clutch design in the 6L80E, they don't hold up well when the clutches start to slip. We didn't even know if it would be repairable. It was and I picked it up a week later. While I was there, we discussed possible causes of the failure and we found that the transmission had undergone previous repairs that were not done properly, exonerating me from causing the trans to fail. We also decided that a larger cooler would be a good idea. A low pressure drop cooler was sourced from Ed. At this point I wish he had opted to install a new pump, for reasons you will soon find out.
Ed had his toque converter service build us a custom, billet faced converter and that was installed here with the rebuilt trans, as well as the new, larger cooler. Installing the larger cooler meant completely re-doing the brackets and lines to get it to fit in behind the grill alongside the power steering cooler.
Two days later I had the trans back in and hooked up to my laptop. Some tuning is required after a rebuild, so the engine was fired up and brought up to temp. The tuning requires that the trans is up to temp.
Excited as all hell, I hopped in the truck and drove it around the neighborhood to find that the same symptoms reappeared. At this point I was utterly deflated. I picked up the phone and called the owner to give him the bad news. A day later the truck was on a transport to Arizona.
Jim Miller runs the Betty Ford clinic for GM electronic automatics (it's actually called Zero Gravity). His resume is extensive including actual design of a handful of GM automatic transmissions so we had faith that if there was anyone on the planet that could help us, it was Jim.
This week brought us great news, that after only five days in his shop, the truck was done and ready to go back home to Texas. During the process, Jim discovered that the pump in the trans was bad (ughh), so it was replaced and that was that...sort of. Not leaving well enough alone, Jim decided to kick it up a notch by adding the shift functions mentioned above.
Upon reflection, it was a very convoluted process. Many hands were involved and that only added to the confusion, but at the end of the day, it should be very fun to drive.
Thanks to everyone who offered advice or support during the process and thanks for watching. I am closing out the build with a handful of pics, but I hope that the vehicle's owner will update the thread as he sees fit and as time goes on.
