That was 1 of the things that turned me off to GV OD the big one was the 3K for the unit.
I have heard of people overriding the below 30 MPH engagement but I dont know what the long term would have on the unit as I have not heard.
I also believe that when GV OD first came out there was not the 30 MPH rule so dont know why they put it in with the newer units?

What is nice of the GV OD is it can be used with a auto or manual transmission where the AA OD can only be used with manuals.
The not nice is the GV OD CAN NOT be used in 4x4 mode where the AA OD can be used in 4x4 mode.

As for the twin stick shifting it is not bad but not as easy as flipping a switch for high / low range in the trans like the 10 speed tractor trailer I drove. Start in low range and run thru 5 gears and flip to high and start over thru the 5 gears or the Chevy C60 dump truck that had a 2 speed rear and had to split the gears just to drive it.
After driving the 10 speed all day and only using the clutch to start & stop, you float the gears, I would hop in the pick up and would kick it out of gear when time to shift and say to self 'what the hell you doing" and use the clutch to get it into gear.
I would also start off in granny as that is where 2nd was in the work truck that you started in when loaded.
Dave ----

 

The trans I swapped in was a zf 5 speed. It's a larger 5 speed found mostly in f250/350 trucks.

Caution on counting the turns to find your ratio; Make sure you turn BOTH rear tires at the same time to find your ratio. If you turn just one and the other is not turning, it will mess the count up.

You have to be careful with that 300 six. It has some low end grunt, but overall it doesn't have a lot of power. If you installed a conventional 5 speed overdrive, it will be more enjoyable to drive without that large gear spread of the 4 speed overdrive. You need to call that guy back you talked to, and ask him how much money he will give you for that 4 speed overdrive. They are considered a pretty lousy transmission. They are weak for towing and the gear spread is too great between some of the gears. Their saving grace is the overdrive.

2000 rpm should be a doable goal, though it might be a little low for 80mph. These trucks are pretty much bricks going down the highway, believe or not I am not sure the 300 has enough horsepower to maintain 80 mph at 2000 rpm, just from the wind resistance. If it did, it would take all it had.

 

If it is a open diff I have not had problems with having 1 wheel on the ground, other in the air and mark the driveshaft and wheel.
Turning the driveshaft and count how many times it comes around for the wheel to make 1 full turn.
He should get the drive shaft to turn a little more than 4 turns for the wheels 1 full turn.

Yes our trucks are a brick when trying to push thru the air at speed but I dont have any problems running 80 MPH @ 2200 RPM.
Heck even at 90 MPH it will maintain that speed for miles if I have to and have to catch out to people on the highway.
I think a lot of modern truck would be shocked if they knew it was a little old 300 straight six staying up with them at 80 MPH even on hills.

I look at what a 302 v8 puts out for power and the 300 six puts out that are not all that different.

🛠️ 1981 Ford 300 Inline-Six (4.9L)

• Horsepower: 117 hp @ 3,000 RPM
• Torque: 223 lb-ft @ 1,600 RPM
• Fuel System: Carbureted
• Compression Ratio: ~8.0:1
• Known for its low-end torque and legendary durability — a real workhorse for trucks and utility vehicles.

🏁 1981 Ford 302 V8 (5.0L)

• Horsepower: ~133 hp @ 3,400 RPM
• Torque: ~243 lb-ft @ 2,000 RPM
• Fuel System: Typically a 2-barrel carburetor
• Compression Ratio: Around 8.4:1
• The 302 had more top-end potential, but in 1981 it was still feeling the effects of emissions regulations.

I dont see the need to get the RPM over 2000 when shifting my 300 motor.
Dave ----

 

[QUOTE=Franklin2;21649261]The trans I swapped in was a zf 5 speed. It's a larger 5 speed found mostly in f250/350 trucks.

First off, thanks for that and all the other info!

I was reading an old thread here last night on an M5OD swap that both of you Daves are in. Tranny swap do not bother me at all but I gotta say I am a little intimidated by the change to a hydraulic clutch! I hate working under the dash!

OH MAN! Youtube screwed me! The video I watched said just the opposite! Now I gotta do it again AND I still dont really know what I have! Frustrating, thinking you know what you have and you don't.

It was a couple of weeks ago he told me that and at the time I found the forums like this one but for much older Ford -- 20s and 30's as I remember. The T170 is not only bolt-on for those guys but the shifter matches their floor hole, so they dont have to cut up 80-year-old floor pans. It may be a crappy transmission for 44-year-old trucks but apparently it is fantastic in 80-90-year-old cars! (and they did not make a lot of them I have read)

So last night I was on eBay. A rebuilt M5 is $1,200. A used as in fresh out of the vehicle still black from oil is listed for $1,200 as well.

Well, I am not pure stock. I have no idea how much HP I am making but its gotta be better than the stock 115. On my road trip last July I hit 90 once on a pass. 90 is about as fast as I want to go in a 44-year-old truck though!

You remind me, though, when they deleted the national 55 mph speed limit and Texas announced, "If you see 55 you can do 70 until we get all the signs changed out" I was excited to go 70. I had a 91 Ford Ranger with the 1.3. I can't remember the mileage but it was tired and they were well known for rounding off the cam and losing duration. Anyway, she just would not do 70 on level ground - maybe 65 depending on wind. 55 uphill. So I got in the habit of just putting both feet flat on the floor in cruise and staying in the right lane. One day, a trooper pulls me over and writes me up for 80. WHAT? I looked back and yeah, he got me on a downhill! Right in front of the trooper, I patted the dashboard and said, "I did not know you had it in you girl! Good job!"

 

Well, I successfully hijacked my own thread! lol!

I started this because I thought there might be an option other than Gear Vendors out there.

When I was looking a month ago, the GV's were in the lower 3,000 like $3,395. Pricey but doable - but still had me looking for options.

Gear Vendors apparently increased their prices. Now they are just above and below 4K depending on the model but as Dave F said at the beginning, with rebuilt 5 speeds available for $1,200 and brand new Tremec 5 speeds available for $2,000 (or a TKX for $2,500) a $4,000 overdrive just makes no sense.

 

[QUOTE=Nerdyredneck;21649355]Found it!