Hey Gary, also... how could I keep my 4W drive?

 

You would just have to regear the front end to match the new 4.10's in the back.

You'd also of course need a 4wd ZF5 and your current transfer case will bolt up to it.

A D70 would also be a reasonable alternative to the sterling. There were 4.10's in those in some trucks.

 

I took an NP435/NP208 combo out and am going back w/a ZF5/BW1356 combo. Mine took some doing, but in your case it would be easy. You won't have to change the transfer case as it'll bolt up to the ZF5 just fine since Ford kept the bolt pattern the same on them. And, since others have swapped from an NP435 to a T19 (Ken Blythen, I think), I'm pretty sure your tranny is the same length as the one I had. Turns out the ZF5 is really close to the same length, so I was able to use the same drive shafts as well. Basically, replacing the T19 with a ZF5 is a bolt-in.

You'll want to start looking for a 4wd ZF5 from a 460. And, you'll have to get a clutch for a 460/ZF5 combo. But, you should already have a 12" clutch/flywheel/pressure plate, so all you will need to do is replace the clutch disc as the ZF has a larger input shaft than the T19 and takes a different clutch.

Here's a comparison of the two transmissions and rear axle gear ratios:




As you can see, your overall gear ratio would be much wider, meaning you can get anything rolling with first, and still have a reasonable highway gear with 5th/OD.

If you'll tell me what tires you have I'll add an RPM column to the spreadsheet so you can see how fast the engine would be turning.

Now, what's it gonna cost? Lots less than another truck. I paid $500 for my 4wd ZF, including the clutch, flywheel, pressure plate, and BW1356 transfer case. However, I've had to do almost $1,000 in parts and labor to it in order to make it "new". So, you might consider buying one from someone who rebuilds them, and that might cost $2,000 or so. Installing that might be $500, although that is just a guess. But, it is a bolt-in if you get the transmission crossmember with the tranny.

As for the cost of the axle re-gearing, I don't know for your axle. But, you will have to change both front and rear. Hopefully someone else has some experience with the cost of those gears.

 

All of the transmissions for these trucks come in 2wd and 4wd versions. You need to buy a 4wd ZF5 as conversion is not easy. But, with that your mechanic will remove the T19 and replace it with the ZF5. All else will bolt back up - with two minor exceptions. First, as said, you need the transmission crossmember from a truck with a ZF5, including the two Z-brackets that go to the upper part of the frame, and it'll bolt in. Second, you need the taller transmission cover, meaning the sheet piece that bolts into the floor and through which the shift levers go. The ZF is taller and requires the taller cover.

 

Were F250HD's solid axle or TTB these years?

Solid axle regear isn't bad, motive gears would be about $200, ykon would be $250, add a master install kit ($100~) and labor if not doing it yourself. TTB is a similar process with a little more labor.

Or maybe another (diesel?) 4x4 already has the 4.10's you want?

 

I was recently quoted ~$600 to regear my 8.8, with labor. I'd expect a Sterling or D70 might be a little more. And of course it all depends on where you are and what the local market is like for this kind of work.

 

Thanks everyone... this is alot to think about!

Rgds

nonrev

 

Don't forget my offer on RPM. Just give me your tire size.

 

An empty F-250HD 4x4 with a big block is going to be over 5000 lbs. Figure at least 6K loaded (maybe more, depending on what "loaded" means to you).

An '85 F-250HD had either a Dana 44 HD TTB or a Dana 50 TTB. The easiest way to regear either is to buy a used center section with the gearing you want. You can then swap it in pretty easily.

If you need to get an axle regeared, a general rule of thumb is about $1000 / axle for parts and labor. Sure, someone will say that's too high, that they've got a local shop that'll do it for $600. but if you go in expecting $1000 you won't be far off, and you might even end up pleasantly surprised if it does come in cheaper.

 

They only offered 3.55's and 4.10's in the larger 4x4 trucks, and the 4.10 is a very common easily found gear, the 3.55's are less common.

Your cheapest solution would be to find a used 89-up f250 or 350 and buy it, and swap everything over, axles and all. If you buy a f350 you will be getting the famous dana 60 straight axle which would be a nice upgrade and increase the value of your truck some.

Just bolt in the tranny/transfer case and both front and rear axles. You could even go newer than 93 if you keep your old transfer case so you can hook up your old cable speedometer.

 

Thanks Gary,

I want to think over my options a bit more. My wife doesn't like the 85 F-250 too much and one thing I know... if your going to be spending a lot of time with someone in the passenger seat that someone better be happy! ha!

 

Wise choice ... Happy wife, Happy life!

-Enjoy
fh : )_~

 

I'd say it's too high cause I do my own gear setup, but I know that most people don't. I also prefer regearing to swapping diffs because there's no hunting and you know that the PO hasn't trashed something, but again, I do my own gears.

I don't really think of a 4x4 as a tow rig though, unless you're pulling on muddy dirt roads in which case it's f350 with HP60 all the way, wouldn't touch a 250 for that.

 

IIRC a ZF5 is not a "drop-in" replacement (although doable) but Tim Meyer may have fixed that situation, don't remember.

 

Chris,
This is an '85 with a 460 already.

TMI has come up with a flywheel and pilot that work with the 335 series engines to properly space the clutch because of the difference in where the crank flange is in relation to the bellhousing mounting face.