Transmission Swap
 

I am wondering if there is an MB tranny (automatic 5 or 7 speed) that would bolt up to an M110 motor.

EZ:

From ~81 thru 85 the 722.3 was used with OM617s and M110s. There is the main case. Use all the internals and the tail housing from the 722.5.

Thanks Frank. The 722.5 seems to be the best the choice for replacement in my '77 280E because it's still hydraulically shifted rather than electronically. The question now is: With the electronic overdrive, are gears 1 thru 4 closer together than in the older 4-speed 722 trannies? This is what I am trying to accomplish.

EZ:

From inception the 722.3 had a 1st ratio of 3.68; mid-1988 that changed to 3.87. 4th 1:1

The 722.5 has a 1st ratio of 3.87. 4th 1:1 5th .75:1

The 722.1/2 boxes have a 1st ratio of 3.98. 4th 1:1

All have a 2nd of about 2.4, and a 3rd of about 1.43.

The only noticeable changes are in the 1st ratios. Does the 722.5 have closer ratios than a 722.1/2? Practically speaking, no.
Significantly closer ratio spreads are achieved with manual boxes, or with some much newer all-electric auto boxes.

Frank, I would rather give up the overdrive and have the 5th gear 1:1, thus allowing closer ratio spreads among all 5. I suppose I´m dreaming.

The 722.5 trans bellhousing is setup for the starter on the LH side, where as an M110 engine starter is on the RH side. You would need to cut the bellhousing off the 722.5 main case & weld in a M110 compatible bellhousing.This has been done by some manual conversions

See Post #2.

If you install the 5 speed with the O/D and then go with a lower (numerically higher) rear end you basically achieve a closer ratio (vs. road speed, not engine speed).

The OP's question, highlighted above, relates to the internal gearbox ratios, and the change in engine speed as the box is progressively shifted from one gear to the next, either up or down. A change in the final drive ratio does not affect the gearbox internal ratios.

The 722.5 (5-speed) has an overall ratio spread of 5.16 (3.87/.75).
The 722.6 (5-speed) has an overall spread of 4.34 (3.6/.83).
The Mustang T-5 (5-speed w/ close 5th) has a spread of 3.69 (2.95/.8).
The Ford AOD (4-speed) has an overall spread of 3.43 (2.4/.7).
The closest ratio T-10 (4-speed) has a spread of 2.20 (2.20/1).

Irrespective of the final drive, the change in engine speed from the lowest ratio to the highest is fixed by the internal gearing.

I agree with this one, it's a round-about way but will get what 280EZRider wants with the right rear-end choice, which is the same final drive ratio from the engine to the wheel, with more gears to pick from.

Sorry Tomy, but Frank is right. I am not interested in changing the rear wheel to engine/transmission ratio - just a transmission that may have closer ratios between its gears internally.