ok i have my 81 f250 currently has the 351m with granny 4 spd 4x4,dana rear.spicer front,.im not sure on exact specifics of the tranny .shes currently covered in snow.iv found a 7.3 diesel motor .i want this because of the gas outrage.im not sure what trannys will fit on this motor???? im interested in keeping it standard 4,5,6 sp whatever, and i need it 4x4. just not sure what trannys i have to play with?????? anything possible in my book any ideas or help is appreciated.


thanks jim

 

well not sure on what trannies fit, the tranny that you have now is a np435(have the same config as you just 2 wheel drive) the 7.3 was used by both ford and International, so i cant help you there.

 

whatever you do dont get the 4 speed. Find a zf 5 speed with od. Any increase in mileage you'd get with the diesel will be ruined without the OD in the 5 speed.

The 5 speed is kind a pain. But its much better than the other options.. Unless you go with an industrial sae rear housing. Of course then you're into all kinds of trouble with the transfer case and getting it to fit in the tunnel.

 

im actually more leaning towards keeping my trans,the t-19 seems to be identical to mine.if i can just do a bellhouse and clutch swap would be best.im sorry but im in love with the granny 4 speed takes me any were and shes a tank.shes more my toy then daily driver.once again thanks a bunch guys

jimbo

 

The ford 289 302 351 bell housing is not the same as the 6.9 and 7.3 bell housing. Your only bolt in options are zf5 , zf6, c6, e4od, and aod. But they have to be the diesel versions that originally came with the ford diesels. Not only for bell housing, but for gearing as well. I am currently swapping in a 7.3 into my 1960 F600. Its a dang good motor.

 

1980/82 F250 351M/400 2WD or 4WD could have either the Borg Warner T-18 or the New Process 435.

1981/82: The TRANS code is listed the Certification Label: F = Warner T-18 / A = NP435.

 

Forgot the T19 4 speed. The diesel bell is just a bit different than the 460 and 351m-400 bells. You would need one from a 6.9-7.3, then all of the factory installs were hydraulic clutches. You could potentially retain your manual linkage with some fab work, as the slave is external on the diesels.

 

I think it's easier to use the hydraulic clutch.. the linkages are hard to get to feel right..

It can be done of course..

Just make sure to make a plate to stiffen the firewall, piece of cake.

 

the T-18 will not hold up behind the diesel..I have 2 blown up behind my diesel T-19 is the better choice,,and the z-f trans 5 speed is what i am putting in my 87 crew cab with a 7.3..the hydralic is a simple swap you will need the reinforced firewall..while we are on tranny's ..does anyone know if the 6 speed on the new truck will fit??

 

International used the same bell housing for there 355, 6.7 and 7.3's. I am getting a 5spd from a 67 IH Dump truck to put behind my 7.3 PSD thats going in my high boy.

 

Does the international version have better ratios? The ford zf has a ridiculous 1 & 2nd. Be nice to have a 5 speed granny low.

 

The 4 speed behind a diesel is nearly worthless. You would run nearly WOT on the highway, have nealrly worse milage than you have now, and your ears would be ringing. Is the 351 dead? Much cheaper to rebuild one of them than convert to a 7.3. Do you know anything about the 7.3 you want to put in? If the SCA level was not maintained, that motor is no good.

Rodney

 

You have to realize that these diesels are not high rpm machines. Whereas you might be able to wind a 351 out to 4500 rpms if need be, you simply cannot do that on a stock diesel. Not that its not reccomended, but its simply not even capable of it. I take that back, if you threw insane amounts of money into a diesel, you could wind it out then. But in stock form, most diesels redline at 2500 to 3000 rpms, and thats maxed out, pegged out, all the way to the governor. So if you have a towing ratio rear end, with a final gear in the tranny of 1:1, then you talking 45mph at redline in top gear. You are almost required to get an overdrive tranny, or change the rear end to a highway ratio.

 

I have 4.10's stock in the 86 250, and it will run about 70 with the stock T19 4 speed. If it had 4.56, maybe 45 top speed would be right, but not for normal gears in these 250s. The truck he is asking about is not a big truck. If I were to try to put one in the old 71 F600 I have, that would be more real as well.

 

One thing to consider is the gear splits. Most of those fairly wide ratio medium duty 5 speeds were really setup to use with a two speed rear axle for optimum performance.

My last manual transmission EVER in a full size Ford truck was a T19 behind a 6.9 (1983 model year) 1-2-3 were perfect, close splits. then a big jump to fourth, then a max out when on the freeway. The split between 3rd and 4th was 43 max in 3rd, 72 in 4th. I cannot believe Ford would put this garbage out. Of course, I was much younger and this was prior to my CDL driving so I was a bit nieve on the test drive, but once i hooked up a trailer - YUK! There was no way I was going to get past that 3rd - 4th gap, so I spent most of my towing time in hill country at 35-38 mph in the right lane, being passed by 80k semi's, with the proper amount of gears!!

That 1983 cried out for a gear below and above in conjunction with the existing 4th - a SIX speed.

Dropping the rear axle ratio lower would have only compounded the high cruise rpm - it really needed, and should have only been sold with a SIX speed.

I also swapped a NP540 5spd (out of a D700 2-1/2 ton dump) into a 1968 dodge D200 3/4 ton, to get four usable road gears (crawler first) and even behind a big block Dodge engine, it was definatly not the optimum as it really needed the two speed rear end to help with the gear gaps. I did find myself holding the transmission in a lower gear than needed, reving the engine much harder than needed just so the rpm would not be too low to keep moving when I shifted. The ONLY saving grace here was the Gas engine, with a larger usable RPM range to play with.

Of course - reformed now, after shoulder surgery and a bad knee/ankle from shifting those balky light and medium duty truck transmissions, there never will be another truck in my fleet with a manual.

Good luck with your project though, just food for thought.

David