A few questions New owners of a 1969 4X4

[stldesign]

1. I understand this truck has gearing in the front that doesn't work with rear. At some point an axle was swapped in to truck.
Current owner says in snow etc. the rear of truck wants to kick out and pass up the front end. Should the gearing be exactly the same front and rear?

2. This is a strait 6 truck which we wanted vs a v-8. Is there a max speed you can drive in 4 wheels drive with hubs locked.

3. What trans and transfer case does this truck have? its a 4 speed granny low floor shift. Both operate well but there is a leak somewhere and we want to replace and seals or gaskets we can.

[jreb333]

it sounds like you may have identified your issue already. generally you want to keep your gear ratios within 1% (3:54/3:55, etc). if you do have a faster gear ratio if the gap is not too bad you can also adjust it somewhat with having different tire sizes front and rear. you do want your faster ratio to be in the front if there is a difference.

[Madman]

First thing, is it a F100 or an F250? Next, when you say "different gear sets" do you know the numbers? I don't necessarily believe that because the back tries to pass the front in the snow means the ratio is off, there are plenty of folks who don't know how to drive in the snow!

What makes you suspect the components aren't original? Have you done the research on the door tag data?

Let's start with this and go from there!

[stldesign]

Just going by what the owner told me.

We test drove on pavement no real way to test the situation with the gearing. Its a f-100 with a 340 6 cylinder. We are in the St. Louis area where every old truck is rusted to hell. This is a rust free Oklahoma tuck but fairly beat up. Picking it up on Monday will see if we can figure out the ratios and get back to post response.

[tnlprt]

Not all of them in the St Louis area are rusted to hell

Where abouts in St Louis are you

I am south on 55

A gear swap for the rear will be the easiest fix if it is a F100

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[stldesign]

Collinsville Ill.
Nice truck.
Thanks for the info.

What about the max speed driving in 4 wheel drive??

[Madman]

The max speed depends on your condition of equipment, but I always went with the thumbrule of no more than 45 MPH in four high.

The transfer case should be a Dana 21 in an F100, which means it should only have 4x4 high range.

[tnlprt]

The current Max speed in 4 wheel drive is Zero till you figure out if the front and rear gears are the same

[Madman]

The current Max speed in 4 wheel drive is Zero till you figure out if the front and rear gears are the same

Good Point!

[stldesign]

According to the door tag (09 on door tag) the rear end is a 3.70 (3.3M) Ford WDM-K -U

One thing that confuses me is that this is the only rear end available for this model but it looks like there were three different front axles available?

4WD - F100 Dana 44-7
3.73 (3.0M)
3.54 (3.0M)
4.09 (3.0M)

Tomorrow we will remove dif covers to check ratios on the dana 44s no tags on them.

[Madman]

If you have a 3.73 and a 3.70, that is not an issues. I've heard of F250's having a 4.09 up front and a 4.11 rear.