You may have seen an article in the August 2023 issue of Transmission Digest called “GM 10L80: A new kind of pump noise,” which goes over how the front cover housing in the 10L80 is fitted with a converter drive gear and idler gear. The idler gear drives the pump’s driven gear, and is press fitted to this housing by way of a ball bearing (see Figure 1). It is this bearing that goes bad, making the aforementioned new kind of pump noise. 

Many of the parts from a Ford 10R80 will fit in a 10L80, but this assembly is not one of them. Buying a front cover assembly from Ford is less expensive than buying one from GM. So, with GM having issues with this bearing going bad, one can be tempted to buy parts from Ford. Dino Romeo thought the same and discovered that there is a difference between them.

Ironically, Figure 2 shows how GM uses helical gears for a quieter operation. Visible in this image is the idler gear that meshes between the converter drive gear and pump driven gear.

Figure 3 shows how Ford uses straight cut gears. 

For Ford’s assembly to be used, a Ford pump would be required to mesh with straight cut gears (Figure 4). 

The good news here is that Ford’s Driven Pump Gear is available separately for $28 under part number HL3Z-7J048-A. Ford refers to this front cover assembly as a “Bracket Support,” and it costs $340 under part number JL3Z-7A130-B, for a total cost of $370 between the two. With GM’s front cover assembly costing anywhere between $460 and $500 under part number 24053051, using Ford’s straight cut gears may be a good solution, saving more than $100 in parts.

Dino Romeo recently had a different scenario which required purchasing a front cover assembly. The low roller clutch is part of this assembly (see Figure 5).

This roller clutch is known to get damaged, which is what occurred in Dino’s 10L80 transmission. In buying the Ford’s loaded front cover assembly, he took the converter drive gear and idler gear off his GM cover and put it in his Ford cover. GM uses a washer under the drive gear which he kept as a set in the swapping of parts. So, this is yet another way to cross-utilize these components if needed.

Read more stories from our Technically Speaking column series here.