T19 to ZF5 1986 F250

[NaiveRancher]

Late to the party. I used a Phenix friction clutch and 13” flywheel behind my 7.3 IDI. It should fit the 6.9, it also comes from the 7.3PSD. Considering Diesel model ZF5 is different than gas and and small block versions. I know mines not a 6.9 but the clutch is nice and smooth and SMF too. Lite chatter.

 

[IDIBRONCO]

The 6.9 and 7.3 IDI have the same bolt [pattern for the flywheels so it will work behind a 6.9. The PSDs use 10 bolts for the flywheel while the IDIs use 9 so they won't work on a 7.3PSD. You could use the clutch and pressure plate for a PSD if you have a PSD flywheel.

 

[the86s]

Update on the swap, I was able to get it all put together after a few tough cross member bolts and about a day spent on getting the hydraulics for the clutch working. I was really happy with the perfection kit I bought from Rockauto, went together super smooth. I ended up using the cross member in my truck and the support/damper block from the donor truck. I did have to use the bolt holes further back in the frame for the cross member and I switched the brackets side to side to get everything to line up. All new hardware in those aside from the very top bolts that are stuck under the cab. Reverse light wiring and speed sensor from the truck fit right up to the zf. Drive shaft fit right up after loosening the bearing mount bolts and replacing with new. For anyone else doing this swap make sure you take u joint cap hardware if pulling from a donor truck, the zf had straps and bolts where my T19 had u bolts. The slave cylinder in my truck ended up coming apart when bleeding the system, luckily I had the one from the donor truck to swap in. If you are having a hard time bleeding the system make sure the master is secure to the firewall and the linkage is adjusted properly. Fought the system for a while thinking it wasn't bled when it just needed adjusted. Fixed a bunch of rust in the cab while I had it apart and threw in some sound dampening material and new carpet. Drove about 300 miles this weekend and super happy with the performance and improved efficiency. Hardly any rollover noise at a stop although I did use 4 quarts of atf compared to recommended 3.4 after reading other posts. Little bit of gear noise when lugging between 1500 and 2000 rpm but nothing to worry about in my mind. Definitely much better on the highway now, the combo of 4 speed, holes in the floor and no exhaust was punishing my ears.

 

[Old Goat]

This last post was a month ago,...
How is she running and still like the 5-spd swap?
Any improvement in fuel mileage?


Goat

 

[the86s]

Truck is much improved for the highway compared to the 4 spd. Old thing keeps up with traffic much better now. Although I haven't got a good trip in to run both tanks down and get a solid average, I noticed an immediate difference if fuel economy. If I was able to stick to just highway miles 18-20 mpg would be well in range. I've been getting 14-16 with some city driving compared to a consistent 10-12 before. I would expect a bigger improvement for trucks that don't have mud terrains and the 4.10 axle. I also did a trip towing another truck on a trailer, nice to be able to use 4th on some of the hills and get back to OD when the road flattens out, with anything lighter than a full-size truck behind me I could have left it in 5th the whole time. For the price of the SMF conversion kit I went with I have been really happy with the feel and performance and would definitely get the same kit if I had to do it again. For city driving the zf makes more noise than the 4 spd at low-mid rpm for sure but nothing too crazy, and the rollover noise in neutral is a lot quieter than I expected after reading some of the other threads about this swap. Aside from that the zf is just a lot smoother shifting, not to mention the 4 spd had 1st and reverse in different zip codes. Really like the spring assist in the zf that brings the lever into the 3-4 column as well. If I end up with another of these trucks this swap would be one of the first things I'd do.

 

[IDIBRONCO]

the zf is just a lot smoother shifting,

This is why I've always preferred the ZF over a four speed.

 

[franklin2]

Only thing I have noticed with the two zf's I have driven, when putting it in reverse, you need to hold pressure on the lever while slowly letting out on the clutch. When you do this sometimes the lever will go a little bit further into reverse. If you don't do this, sometimes the lever will pop forward out of reverse and make a awful grinding noise. If you keep pressure on the lever while slowly letting out on the clutch, it never does it.

 

[the86s]

Yeah, I have noticed the same thing. Luckily, it's pretty easy to notice if its fully engaged or not. I'm sure if I park it for a bit and come back I'd get complacent and forget. One thing that helps is my 4 speed was getting real hard to find reverse with so I had to do the same trick with that one or even roll a bit forward/back to get it fully engaged.

 

[IDIBOBS]

I would expect a bigger improvement for trucks that don't have mud terrains and the 4.10 axle.

As far as gearing and axle this would really only hold true while driving with no/light load in flat level ground at speed. Any other time, city, hauling towing, hills, mountains ect usually the same or better milage happens with lower gears since you can upshift faster and stay in higher gears longer. and use less fuel to get the same hp and tq to the ground. Remember gears are torque multipliers.

 

[the86s]

That was the intent with keeping the 4.10s. Not trying to squeeze all the mpgs out anyway and it definitely tows and handles hills better this way. Super handy to get into OD at lower rpms in the city too. Way easier to match traffic speed on the highway, basically drives like an auto above around 30, granted not the best acceleration in that case but gives the left leg a rest in slowish rolling traffic. See a lot of that on my commute.

 

[Old Goat]

the86s thanks for the feed back on your over view of your
5-spd conversion.
I like the T-19 except for 1st being a bit too high starting on a grade with a load, or reverse backing up, especially backing into my car trailer at 10 MPH, plus the 3:55 diff.
4th in both gear box`s should be direct. 5th with the OD is a plus.
With not going into reverse sometimes it`s the gears not lining up, I let the clutch out a bit to get then to move a bit and she goes right in. No synchros for reverse. Maybe the 5spd is the same problem?
I have never driven a 5 spd ZF, plenty of 10 & 13 spd Road Rangers,
especially some with no synchros.

One of these days I`ll eventually come across a 5-spd.
I did come across a GV at PNP a while back and a 3 spd Brownie
from another IDI guy several years ago.

HMMM a 4spd, with a Brownie and a GV, what a combo of gears.....
Just kidding.
Lately been getting 18+ MPG with the T-19 & 3:55.

Being a 6.9 NA, and now almost 365K, she is a bit slow on a steep
grade pulling a load. Was hauling 3 Cords of Fire Wood on my Car Trailer from Bosie, ID area, taking Hwy 95 south Or - NV, to I-80 some steep looong grades. 2nd gear doing 24 MPH.
Don`t know how a 5-spd would help in that set up.
Maybe a 7.3 Turboed and 5-spd, maybe be in 3rd gear pulling a bit faster...IDK. It`s all about power and gearing...

Goat

 

[the86s]

Yeah, mine has around 328K so I feel your pain on the miles wearing things down. Pulling that 7.3 IDI F250 for my buddy with a not so light trailer and too many spare parts in the bed wasn't the easiest for it. I was able to stay in 4th for most of the hills but the longer ones I kept losing speed and debated 3rd. No different than the 4 spd on that trip but it's nice to have OD as an option when the terrain allows for it. I have been debating a turbo setup for this thing since before the trans swap. Don't feel like it's as needed now but would be a good power addition to help in the hills. My truck started life with an equipment dealer, so it had been used for towing a lot before I picked it up, not to mention whatever the other owners have used it for. The 4 spd appeared to be factory so even if I didn't make towing easier by gearing, I at least have a lower milage trans to put some trust in. I wouldn't say reverse is much different with the 5 spd but I'm sure the 3.55s make that tough, I feel that mine backs up a little quick even with the 4.10s. I lucked out with finding the 5 speed I swapped in, good luck in your search if you plan to do the swap.

 

[KansasIDI]

Maybe a 7.3 Turboed and 5-spd, maybe be in 3rd gear pulling a bit faster...IDK. It`s all about power and gearing...

I had such a setup in an 86 F250 with 3.55s. I was usually in 4th to pull up hills, with 12-14k lbs behind me. I didn’t shift to 5th unless I was trying to go over 70

With my 91, which has 5.13 gears, and an intercooled turbocharged 7.3 and the ZF5 5 speed, I am always in 5th to pull, unless at speeds under 55. It will pull any load at any speed, just kinda wrapped out on the interstate highways and such. Max speed of 84, in 5th gear on the governor. If you put 20k lbs behind it, then she’ll still lumber up to 84 if you keep the foot down. EGTs have never been a problem with this big intercooler behind the grille.