4L80-E Shift Lever Kit for Custom Transmission Builds

• Short manual shaft with late-style flat angles ideal for use with many aftermarket shifters
• O-Ring helps prevent case leakage
• Zinc-plated for corrosion protection

Working on custom performance transmissions requires a different skill set than regular, OEM transmissions for daily use. Everyday builds often require going to great lengths to ensure everything is original and works like it did when new (correcting problems along the way). By contrast, a performance unit can see many things adjusted, customized or machined to tweak it for optimum reliability and function. That can include swapping one OE part for another when there’s a variant better suited to performance applications — think of a stock drum that holds more clutches or a planet with additional pinions. Collecting all these detailed preferences is what most performance transmission builders excel at.

One detail that came to the attention of Sonnax is the difference between 4L80-E early-style (short) and late-style (long) manual shafts. If all you ever deal with are OEM applications, you would never know there is a subtle variation in the shift lever flat angles that can make 4L80-E custom builds tricky.

Take this typical scenario: you use an aftermarket shifter with a late-style (long) shaft transmission and it works OK, but if you need clearances for headers, etc., and convert to an early-style (short) shaft, you can’t make Park range and/or Low range on the shifter work (Figure 1)!

This problem exists for both OE short-shaft transmissions and direct replacement, aftermarket short shafts: as shown in Figure 3, the early-style shaft’s flat indexing causes it to operate at different angles than the late-style, long shafts.

Once the root cause of this dilemma came to light, the solution was obvious: give builders a unique shaft that combines a short-length shaft with the flat angles of a long shaft (Figure 2).

Figure 1 – OE Shaft (Short, Early-style)
Exaggerated shift lever arm angle does not work well with aftermarket shifters.

Figure 2 – Sonnax 38512-03K Shaft (Short, Late-style)
Proper angle for use with aftermarket shifters.

And that’s what you get with the Sonnax shift lever kit 38512-03K. It’s the easy way to install a short-length manual shaft for extra exhaust clearance that also delivers trouble-free operation with many aftermarket shifters.

This unique upgrade is configured to work with the ’95-later detent rooster comb that features a square identification hole and .316" wide internal flats. It can be retrofitted into early 4L80-E units, but requires using a ’95-later detent rooster comb.

Use this kit or any of the other three manual shaft options from Sonnax to help you turn out top-quality builds for both everyday units and custom performance applications.