Two transmissions, both stamped 8HP70. One came out of a Jaguar, one out of a Ram. They share gear ratios, they share the basic architecture, and they will not share a single piece of your swap hardware.
This surprises people, and it explains most of the fitment questions we field. ZF supplies the 8HP to a long list of manufacturers, and each specified their own version. The gearsets and clutch packs are common. Almost everything you physically interact with during a swap is not.
The five places same-family units diverge
1. The bellhousing is part of the case
This is the big one. On the 8HP the bellhousing is not a separate bolt-on bell — it is cast into the main transmission case. The engine mounting face, the bolt pattern, the starter provision and the overall bell geometry are all fixed characteristics of the unit you bought.
A BMW-sourced 8HP70 and a Dodge-sourced 8HP70 have physically different castings where they meet the engine. There is no adapter that converts one into the other. That is not a gap in the aftermarket; it is a consequence of how the transmission is built.
A 2JZ going in front of a BMW 8HP needs SKU 81001. The same 2JZ going in front of a Dodge Ram 8HP needs SKU 81003. Same engine, same family number on the transmission, entirely different adapter.
Manufacturers also optimised their castings differently. Passenger car applications tend toward weight-optimised ribbed cases; truck and off-road applications tend toward heavier, thicker sections. Even within a family, physical size and mass vary meaningfully by donor.
2. The output flange varies — and so does your driveshaft plan
The rear output is the second place where OEMs went their own way. Bolt circle diameters differ. Flange styles differ. Some applications use a flex-disc arrangement, others a conventional or slip yoke output.
| Donor transmission | ASE driveshaft adapter | SKU |
|---|---|---|
| BMW transmission, 96mm bolt circle | 96mm to 1310 / 1350 U-joint flange | 13860-1 / 13860-2 |
| BMW N54 / N55 / B58 8HP, 105mm bolt circle | 105mm bolt circle flange adapter | 11418 |
| Dodge Mopar 8HP50 / 8HP70 | Mopar to 1310 / 1350 | 11421 |
| Dodge Mopar truck 8HP70 | Mopar truck to 1310 / 1350 | 11422 |
| Jaguar 8HP45 / 8HP70 | Jaguar to 1350 | 11425 |
Note that two of those are both BMW, and they are different parts.
3. The converter is matched to the donor engine
Converters vary by application in diameter, stall characteristics, lockup clutch design and damper arrangement. Diesel applications generally use heavier converters with substantial torsional damping to handle combustion harshness; petrol applications use lighter units with different stall behaviour.
The converter is also the heaviest single rotating component in the transmission, so it is a large part of why nominally identical units weigh differently on a scale. More importantly, it is a large part of how the car will feel to drive. We cover the selection logic in our guide to torque converters and stall speed on 8HP swaps.
4. The oil pan tells you what the donor was for
Most passenger car 8HP applications use an integrated pan and filter assembly in a moulded composite housing — light, and replaced as a unit at service. Some truck and towing-oriented applications use deeper or metal pans for extra capacity and cooling.
For a performance swap this is an opportunity rather than a problem. Fluid capacity and heat management are directly linked to clutch pack life, and the factory pan was not designed around sustained abuse.
5. Cooling provisions are not standardised
Some OEMs bolted a heat exchanger directly to the transmission case. Others plumbed cooling lines out to a remote cooler elsewhere in the vehicle. That decision changes what ports exist on your unit and what plumbing work is ahead of you. Look at the actual unit rather than a reference photo of a nominally identical one.
Five patterns covered — BMW 96mm and 105mm, Dodge Mopar car and truck, and Jaguar — all converting to 1310 or 1350 series U-joints.
Browse the range →Fits 8HP45, 845RE, 8HP50, 850RE, 8HP70 and 8HP75. Adds volume and serviceability over the factory composite pan and filter assembly.
View product →The family number tells you the torque capacity and the gearset. The donor vehicle tells you everything about whether parts will fit. When you contact a supplier — us or anyone else — lead with the donor vehicle and the nameplate, not just "8HP70."
Start from the donor, not the family number
Our ZF 8HP conversion kits are listed by donor transmission for exactly this reason. We build for BMW, Dodge Mopar, Dodge Ram, Jaguar and EcoDiesel sourced units, across 2JZ/1JZ, K20/K24, SR20, LS/LT and BMW N-series engines. Everything is designed and CNC machined in Lakeland, Florida.
If you have the transmission in front of you and are not sure which category it falls into, send us a photo of the nameplate and the rear output flange. Those two images answer most fitment questions in a single reply.