Packard Forum Index » Pre-War (1899-1942)

We want to change the ring & pinion gears in our '38 Packard Six model 1600 4-Dr. Touring Sedan. The ration is 4.54:1.

We've seen ring & pinion sets and 3rd members listed for car years older & newer than ours.

We would like to find out, if possible, which years & models are interchangeable with ours.

Can anyone tell us where we can find out this information?

Thanks.

Perhaps one of the savvier souls here gathered can confirm,
but a 3.9:1 rear cog out of a junior bathtub delivered without overdrive or '51-'52 Ultramatic 200 might fit. If you're going to change rear gearing, go to the tallest you can find, because Packards are laughably undergeared.

Packards are laughably undergeared.

Yes - for today's roads and driving habits but not for their era and prevailing conditions of the time. Their ratios were pretty much the same as the other heavy cars of the time, and some of the others had even higher ratios.

PS - I just looked up some just-prewar axle ratios for some of the heavier Chrysler, Buick and Cadillac chassis - several models of each were between 4.5 and 4.6 to 1 so Packard wasn't really out of step for the times.

Jampard - have you checked a Hollander's for interchange information?

Check the parts book on this site and you can easily find out what other years will fit your car.

The parts book takes quite a bit of searching, but here is a basic summary of units that have a ring & pinion which should fit the 1938 carrier:

1937 - 39 Six & 120
1940-42 Most models except 6 cylinder
1941 Clipper
1942-47 Super & Custom Super Clipper
1948 - 50 Custom 8

In most cases the entire carrier assembly should bolt in except for the 1937 models which still used the angled housing

1942 - 47 Junior Clippers are different as are 1948 - 50 Standard & Super 8 models

Thank you very much for this information that you dug up. This will be very helpful in our search.

I started looking in the '35 - '41 Packard Parts Manual and found quite a few model numbers that had the same Ring & Pinion part number. I'm trying to convert all the different model numbers to model names.

The '38 Six 4.54:1 Ring & Pinion part number is supposed to be 900066. These are the model numbers I found that have the same Ring & Pinion part no.: 115C, 120C, 120CD, 120CA, 138CD, 120B, 120BA, 120, 1600, 1601-1D, 1700, 1701, 1703, 1705, 1801-T1900-1901, 1801-1901, 1803A-1903A, 1805-8-1905-8.

Now, all I have to do is find a NOS set, or a set in very good condition. I'm looking for maybe a 3.54:1 ratio.

The lowest Packard offered was 3.92:1. I have a used ring/pinion in this ratio if you desire, $450. The only lower option is a newly produced 3.54 set that is advertised. Packard never made this.

Buy Flackmaster's 3.92 pumpkin AND retrofit overdrive. Then you'll have a wonderful road car. Any competent shop can cut down your existing driveshaft and balance it, or get the right driveshaft out of a '39-'41 Six, or '42 110 conv. parts car, as these all share your 122-inch wb, that came with overdrive. It's hard to overgear a Packard, and your 245-ci six was spunky enough to be offered as a marine engine in 1950, and in White Trucks in the '50s.

Didn't realize the 3.92:1 from senior cars would fit, which is why i suggested earlier the 3.9:1 differential from a junior tub, or 1951-52 200 w/ Ultramatic. The above poster's right. No junior Packard came with a 3.54.

A 3.9/3.92 if it fits will still leave you with enough snap around town, while giving you long legs for relaxed cruising in overdrive. A 3.54 might be a little tall, strain your pressure plate, but i defer to others' experience. I know a fellow who so geared (3.54) a junior '47 Clipper 8 club sedan with overdrive, but said it was too tall, no power on the freeway, and so went with a 3.9.

Any Packard can benefit from more relaxed, taller gearing, being wonderful, torquey cars.