Advance Adapters GM 6L80E / 6L90E 6 speed automatics to the GM & Dodge

SKU: 1L69E | MPN:  50-9551

Sale price$655.20 USD

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Advance Adapter

This adapter kit will adapt the New GM automatics 6L80E or 6L90E 4WD to either GM & Dodge NP205 Figure 8 bolt pattern NP205's. Kit 50-9551A, 6L90E adapter assembly includes new female 29 spline NP205 input gear and shaft, NP205 adapter ring, 6L90E conversion tail housing, input shaft bearing and fastening hardware.

Kit 50-9551B, 6L80E adapter assembly includes new 32 spline female NP205 input shaft , NP205 adapter ring, 6L80 conversion tail housing, input shaft bearing and fastening hardware

Transfer Case

The kit is designed for GM NP205 figure 8 front bolt pattern NP205 10, 27 or 32 splines and Dodge NP205 figure 8 bolt pattern 23 & 29 spline NP205 transfer case. Please note that there is no machine work needed on the GM & Dodge NP205 with big bearing bore cases (29 & 32 spline inputs). Note: Small bearing bore case Dodge 23 spline & GM 10, 27 spline NP205 transfer cases will need the front input bearing bore machined to big bore specifications.


GM's new Hydra-Matic 6L80 & 6L90 transmissions are the first of a new family of modular six-speed rear-drive transmissions. The transmissions feature two overdrive gears and a wide, 6.04:1 gear ratio spread to improve performance and fuel economy when compared with conventional four- and five-speed automatic transmissions. With two overdrive gears, engine rpm is reduced by approximately 9 percent at 60 mph - a reduction to about 1,500 rpm. Lower engine rpm can bolster fuel economy because less fuel is used. A lower-rpm cruising speed also enhances smoothness and reduces noise heard in the vehicle's cabin.

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