4.10 to 3.54 gear swap??

[young_gun17]

I got a 93 d250 with 3.54 gears. I just bought a d350 chassis and bed. i want to do a dually swap on my pickup, but I don't want the slow 4.10's. I wanted to swap the hubs but from what I read the spindle, bearing, and bearing sizes are bigger on the dually axle. Can I swap 3.54's into the dually axle out of the single wheel axle? Thanks

 

[Deathrowdave]

If it is a Dana 70 it’s good to go . It one (SRW) is Dana 60 and one (DRW) is a Dana70 then no go .

 

[JR]

Depending on transmission and intended usage, you may want to rethink that. I had both in a 2nd gen and the 3.54 was too tall with a 4 speed auto for what I towed. I much preferred the 4.10s.

 

[young_gun17]

i rarely tow. very rarely. if i do, i’m not going far and i’m going slow.

 

[RobertGray]

Given your usage I believe you will be better off with a 3:54 rear axle ratio. I have never towed and if I did tow a big load I would go slowly and not far. With a 3:54 I can cruise on Irish highways at 70-75 miles an hour and it still runs sweetly if I let the speed creep up to 80+mph on the clock. The speed limit is 120 kph = 75 mph. This is with 265/75 tyres instead of 235/85s.

 

[HHhuntitall]

Personally, I've never found too tall a gear, as long as it will start rolling when loaded.... Having driven many 10, 13, 15, and 18 speed trannies, there is always the downshift option.... seeing as later first gen autos have an OD lockout, I think you'd be fine, in my opinion. Personally, I'd try to find a whole axle assembly.... Swapping gears is a technical challenge, and sometimes labor intensive. I believe you have a Dana 70u dually axle, IIRC, and most likely a 60 or 70 rear in the D250, so it's not possible to swap those gears. A gear set can be bought reasonable, but has to be set up correctly or won't last. For the cost of the gear set, you can usually find a donor axle to swap in.... But these 1st gen parts are getting harder to find....

You'll need to identify your axles to make certain. There should be tags bolted under the diff covers, which identify axle ratio and build codes.

 

[RWherley]

I swapped my 350 from 4.10s to 3.54s, it was one of the best things ive done to my truck, empty i come off the line in 2nd and when ever i do hook to a trailer i just use 1st and run the rpm a little higher before shifting.

 

[young_gun17]

did you just take it to a rear end shop and have them swapped?

I swapped my 350 from 4.10s to 3.54s, it was one of the best things ive done to my truck, empty i come off the line in 2nd and when ever i do hook to a trailer i just use 1st and run the rpm a little higher before shifting.

 

[RWherley]

No I did it myself, but I have the correct tools to do it, the most important part is to make sure you have the back lash right in the gears

 

[surfbeetle]

On my 95, I took it to a gear shop and had them swap the 4.10's to 3.54 gears, at the time it was around 2,000 for parts and labor and I added limited slip as well. I have the NV4500 manual that has the low granny first gear. With the 4.10 gears, I never used first to start unless towing. Once swapped, I use first quite a bit more. Also at the time I had the gears swapped, I also changed out the plate in the injection pump and gained more power. Towing my 11,000 lb fifth wheel hasn't been a problem.