January 05, 2023

How to Identify Allison® LCT 1000 Input Shafts

Did you know that there was a change to the input shaft in the Allison LCT 1000?

In model year 2017, the shaft went from 25 to 26 splines. The 25-spline version has splines that extend all the way to the tip of the shaft. The 26-spline version has a smooth tip at the end of the shaft.

Another quick way to verify which shaft you have is to take a caliper measurement of the spline O.D. The caliper will show approx. 1.273" for the 25-spline version and 1.320" for the 26-spline (Figures 1 & 2).

Figure 1 – Shaft Spline Comparison
Allison LCT 1000 – Shaft Spline Comparison
Figure 2 – Measure Splines with Caliper
Allison LCT 1000 Input Shafts – Measure Splines with Caliper

Related Units

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