8l90 need help....
09-25-2020, 05:44 PM
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8l90 need help....
2016 gmc sierra 6.2 8l90 trans
tsp cam, whipple 2.9, 3200 stall(circle d)
Right after my last dyno tuning session where we were tuning for the cam and new converter is when this all started. Dyno pulls went great made awesome power, with no slip at all in beetween shifts. Get down the road about 5 miles and it acted like the converter **** the bed. Check the trans temp and she was at 170. Just neutral for every gear. Turn it off let it sit for 10 minutes or so and shes good got about another 5 miles. Temp staying right around 170-180. This being a brand new converter I was pretty pissed, tuner said when they drained the fluid it was pretty black and would bet the trans is just finally dying from bad fluid being in there for so long, k bit the bullet swapped in a brand new trans and converter, all is good for the day and today it just did the same exact thing with the wife in the truck(she hates going fast so I didn't floor it once) I've gotten it down to about 45 minutes to pull this trans so I swapped in the stock converter for ***** and giggles and it does the same exact thing. Fluid in this new trans looks perfect as it has 25 miles on it. No metal in the filter, nothing on the magnets.Any ideas what is causing this? This thing ran for 70k miles with the whipple only at the same boost level and never skipped a beat. Any guesses or information would be helpful. As I'm stuck tbh.
tsp cam, whipple 2.9, 3200 stall(circle d)
Right after my last dyno tuning session where we were tuning for the cam and new converter is when this all started. Dyno pulls went great made awesome power, with no slip at all in beetween shifts. Get down the road about 5 miles and it acted like the converter **** the bed. Check the trans temp and she was at 170. Just neutral for every gear. Turn it off let it sit for 10 minutes or so and shes good got about another 5 miles. Temp staying right around 170-180. This being a brand new converter I was pretty pissed, tuner said when they drained the fluid it was pretty black and would bet the trans is just finally dying from bad fluid being in there for so long, k bit the bullet swapped in a brand new trans and converter, all is good for the day and today it just did the same exact thing with the wife in the truck(she hates going fast so I didn't floor it once) I've gotten it down to about 45 minutes to pull this trans so I swapped in the stock converter for ***** and giggles and it does the same exact thing. Fluid in this new trans looks perfect as it has 25 miles on it. No metal in the filter, nothing on the magnets.Any ideas what is causing this? This thing ran for 70k miles with the whipple only at the same boost level and never skipped a beat. Any guesses or information would be helpful. As I'm stuck tbh.
