F450 Going from 4r100 to zf5 or zf6 with 4.88

[yngbuck19]

Here is a question for a friend of mine with a F450 dually and he just wants to know which manual trans would have a better final drive with the 4.88 gears he has and what would be need for the swap a basic list of parts main concerns are axels and yokes transfer case and comfortable cruising speeds and decently low rpms when cruising thanks I know this is a tall order and any info is appreciated!

[7.3HeavyHauler]

a donor truck will eliminate all your parts needs, as far as gear ratio go to randys ring and pinion they have a calculator that will tell you what the rpm's will be.

[yngbuck19]

His truck is the crew cab custom flat bed style Superduty what would be a good donor truck for that and I think the final drives for the two manual Trannys are about identical in final drives how does the auto 4r100 final drive compare to the manual zf6 tranny he tows a 35ft goose often hauling tractors and dozers thanks for the response

[7.3HeavyHauler]

any manual truck is a good donor, provided you can get one with the tranny still in it, as far as gear ratios, look at randys ring and pinion website, and yes it is better to tow with a manual than an auto especially when your talking about dozers and what not, but thats my personal opinion

[dieselcrawler]

I love towing with my man trans truck... wish my dually was a stick too.

The ZF-6 is a better choice, it has the same or simular final drive ratio, but the added low gear is great.

['01SilverBullet]

From what I've heard, the 6 is stronger, too. But as far as final RPM is concerned, with 4.88s, that motor is going to pretty wound up at speed, even in high gear.