The only difference between a 4L80E & a 4L85E is the Reaction & Output Carriers, The 80E uses 4 Pinions & the 85E uses 5 Pinions. They use the same case. The 4L80E has a max input torque rating of 440 ft lbs, And 460 ft lbs for the 85E. But GM was putting 455 ft lbs through 4L80E's in the 8.1L (L18) equipped 2500 Suburbans & Avalanches for 2001 & 2002 model years......Though they were GVWR limited. I've built several 4L80E's for 3500 DRW Cab & Chassis Duramax vans because the 4L85E weren't salvagable.....The 4 pinion carriers are not & never were an issue. Torque rise killing the Direct Clutches, TCC lining burn-up, Forward Clutch failure from forward drum bushing wear allowing the Turbine Shaft to destroy the sealing ring lands in the forward drum, And Overdrive Roller Clutch failures are the main issues which also afflict the 4L85E. Everything besides Forward Drum bushing wear can be mitigated with modifications. Even the damaged caused by bushing wear can be mitigated by machining the forward drum ring lands oversize & running oversized sealing rings. TCC lining wear can be relieved NOW with HP-Tuners also allowing you to block the EGR & turn off the EGR DTC's.....Killing 2 birds with one stone!
Originally Posted by dareo
Thanks Cline. I saw on some vendor sites that HP was backwards compatible with Dex VI but i guess i won't experiment. This van has a re manufactured trans with a case stamped 24208421 and that seems to correlate to a 4l80e. Does a 4L85E use the same case? Maybe this thing is just gonna blow up soon and will need to be upgraded so i'l leave fluid alone.
Originally Posted by clinebarger
Dexron LV/HP is not applicable to any other units besides the 8L45E & 8L90E, Whether or not it will cause issues is anyone's guess.