Jax' L99 F350 7.3L Truck rebuild . . . .

Jax · Jan 6, 2020

Greetings, all;

I have been looking for a HD - any make - to pull a bigger travel trailer but all I find is a lot of people too super-proud of their vehicles with 200k+ mileage. Therefore, I bought this to build my own - the engine is a literal basket case...

1999 FORD F-350 SD LARIAT Ext Cab LWB 2WD
7.3L V8 OHV 16V Powerstroke . . . Orig mileage 245083
~~5 speed~~ 6 speed manual transmission

I want to build the entire power train - I suspect the rear is not limited slip - and want to fix everything Ford did not do right when it was built. I want to make it as efficient as possible in AZ's 120F heat to the northern regions.

I have rebuilt small block chevys, two motorcycle engines, but this is my first time on Ford and rebuilding a diesel (although I have worked on them).

Thank you all for all the wisdom posted on this website.

Best recommendations for aftermarket upgrades?

Cummins Junkie · Jan 6, 2020

What was wrong with the engine that made you want to rebuild it? Also, the kind of power you are trying to make will determine what people recommend to you.

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Jax · Jan 6, 2020

Thanks, Cummins Junkie -- First, the engine parts were in a crate, totally disassembled.

The engine broke a ring and pinged on top of a piston.

No scoring in cylinders but a definite ridge.

245K miles and I would like to get the same on the rebuilt power train. Efficiency and towing are the goals.

Cummins Junkie · Jan 7, 2020

Well, there is an absolute ton you can do to these things. Engine-wise is a book in itself. Upgrades/fixes I could list off the top of my head (that I personally would recommend or do if I were in your position):

-Up pipes. Factory ones tend to be leaking badly by the time 100k rolls around. I would go with BD Diesel's pipes. Great quality, I have installed numerous sets myself.

-Fuel bowl delete. I would do that because the factory bowl tends to be a common source of fuel leaks. Its a bit more in-depth in that this requires a regulated return kit with an aftermarket pump/filtration system (such as an Airdog, Fass, etc). Driven Diesel makes one of the best reg return kits out there, or you can build your own with the help of the numerous threads on the subject.

-Charge air cooler and CAC pipe boots. Your truck might already have an aluminum CAC, if so, then no upgrade is really needed. But you can and should get rid of those factory rubber boots and clamps on the pipes, which may blow off under heavy load and boost, and upgrade to BD Diesel boots and clamps. I believe they are hands down the best ones out there.

-Turbo pedestal. Factory pedestals have an oil cooled solenoid for actuating whats called the exhaust back pressure valve on the turbo (which I would also delete). It is a common source of oil leaks, so I would highly recommend getting a non-ebpv pedestal instead.

You should look into trans rebuilds or upgrades too if you want it to last. Those 4r100s are known to be just barely enough....

There are so many other things you could do, and I recommend you browse some online retailers and product manufacturers (such as BD or Driven Diesel) and see all the options for yourself. It should also go without saying, but the items listed are just my opinion at the end of the day, and Im sure they could be contested.

Jax · Jan 7, 2020

Cummins Junkie said:
You should look into trans rebuilds or upgrades too if you want it to last. Those 4r100s are known to be just barely enough.....

Thank you for your insights!

However, I have the 5-speed manual. I am going to have it rebuilt - Does anyone have opinions on looking for a 6-speed?

edit -- I actually have a 6-speed!

Jax · Jan 7, 2020

ZF5 versus ZF6 - I am keeping my ZF5

Thank you, PowerStroke Nation!

My first major decision - I will keep the 47 - ZF5 manual transmission.

Mostly due to this thread: https://www.powerstrokenation.com/f...orums/18-1994-1997-obs-power-stroke-aftermarket-performance/120534-zf5-zf6.html

Of course, I will have it rebuilt.

The primary reasons is that there is not that much gain on the swap. The ZF6 will require an oil cooler, and moving a crossmember. The ZF5 is strong, I don't need the lower Low gear, and the high gears are comparable.

Jax · Jan 7, 2020

Differential cover

Did all the reading, and I am going to go with the stock Ford '08 aluminum dff cover. It's finned and I don't care that much about looks.

cjfisher · Jan 7, 2020

Jax,

I have an off color opinion on the transmission... I would not have based my choice on reading the post. Reading through the link I kind of think that Bradbilt's thinking may be backward. I have a 1997 F350 that had a ZF-5/47 in it... I found that pulling heavy loads that I didn't have enough gears (or the right gears - rear end is 3.55) to keep my load moving down the road (not that I mind gearing down). What bugged me was how high I had to rev the motor before a shift in order to stay on top of the turbo. Keep in mind my engine is completely stock (perhaps with the added torque in later models this is not as much an issue). The other bit I didn't like was having to ride the clutch to back up my loads as the reverse is somewhat shallow with a 4.66 reduction. I ended up switching to a Roadranger 10 speed which allows me to better utilize the available torque. The calculations I use to compare transmissions (mirrors the ratios that you can find on the Roadranger website) is (GearX - GearY)/GearY = %. IE for the ZF5/47 you'd have (5.08-2.6)/2.5=0.95 (you can multiply the 0.95 by 100 to get the percentage). The 0.95 is the percent reduction between gears. For the ZF5/47 I got:
1-2:0.95
2-3:0.699
3-4:0.53
4-5:0.298

On the ZF6
1-2:0.75
2-3:057
3-4:0.615
4-5:0.30
5-6:0:0.388

My transmission choice would have been based on the fact that a well designed transmission generally has ratios that have less and less reduction the higher you shift and (at minimum they have consistent ratio reductions - my 10 speed has between 0.25 to 0.30 reductions all the way down). When you look the ZF6 this is not the case as the reductions tend to jump around (however, the deeper reverse in the ZF6 would have been nice). If I hadn't changed transmissions all together I think the ideal would have been the Zf5/47 with a 3.73 rear end. Good luck on the build!

Cj

PS.. You'd also have to shorten/lengthen the drive lines with the ZF6 speed

Jax · Jan 8, 2020

Transmission, Rear end . . . . smh

Thanks, CJ;

However, I finally got the truck body towed to my house, and I have the door sticker info.

Manufacture date was 12/98, yet the Transmission is supposedly the 6 — Six-speed manual ZF (M6HD-6), and the rear end is 3.73 limited slip, F-350, single rear wheels

I thought I read that the early 1999 were all shipped with the ZF5. Sigh. Come daylight, I will take a better look.

Jax · Jan 8, 2020

Re: Transmission, Rear end . . . . smh

Jax said:
Thanks, CJ;

However, I finally got the truck body towed to my house, and I have the door sticker info.

Manufacture date was 12/98, yet the Transmission is supposedly the 6 — Six-speed manual ZF (M6HD-6), and the rear end is 3.73 limited slip, F-350, single rear wheels

I thought I read that the early 1999 were all shipped with the ZF5. Sigh. Come daylight, I will take a better look.

CONFIRMED - my early 99 has the ZF6 Transmission.

cjfisher · Jan 8, 2020

Jax,

There is a blurb about single mass flywheels being introduced for 1998 models: 7.3L Power Stroke Diesel Model Year Changes . This may also be of interest: Power Stroke Horsepower & Torque by Model Year . I don't really know when they made the switch. If your interested search for "Project Jumbo" - this is my truck and has the details about the transmission.

Cj

Jax · Jan 8, 2020

Single Mass Flywheel versus Dual Mass Flywheel

I could not find a definitive answer here, so I am posting this link for others that may search.

https://www.eeuroparts.com/blog/single-mass-vs-dual-mass-flywheel-why-convert/

It's a good explanation.

That said - does anyone have a favorite SM flywheel? Mine is a hot mess. :frown:

Jax · Jan 8, 2020

Jax' 1999 F350 7.3L Truck Door Sticker

BM External Paint Code
71 Region Code
Domestic Special order Code (none)
158 Wheel Base Code
5 Brake Code
2X Interior Trim Code – Cloth Captains chairs Med Prairie Tan
Tape / Paint Pinstripe Code (none)
9 Radio Code – AM/FM cassette clock
D1 Axle Code - 3.73 limited slip, F-350, single rear wheels
6 Transmission Code - 6 — Six-speed manual ZF (M6HD-6)

JB Spring Code –
Front Springs
• Base part number — 5310 (RH/LH)
Rear Springs
• Base part number — 5560
• C — 5588, auxiliary rear spring
• D — 5588, auxiliary rear spring

Jax · Jan 8, 2020

Re: Jax' 1999 F350 7.3L Truck Flywheel

May I cry, please? :crying:

Jax · Jan 8, 2020

Can anyone identify this axle / differential?

The tag code is not in the Workshop Manuals I downloaded.

Diff Tag: 3S 409 C
?L 73 10 5 8M11

Web search - https://www.diyford.com/ford-axle-history-identification-ford-differentials/

The axle tag typically has two lines of numbers and letters stamped on it. The format has changed over the years but mostly follow this sequence:

The top line typically starts with a three-digit axle model code (or the prefix of the part number), followed by a dash, and then the suffix. The axle model codes are interchangeable, typically the suffixes are different for a revision change but the axle is still interchangeable with one having the previous suffix.

There may be a second dash and more numbers and letters on the top row if there are specifics that are unique for interchange information. Typically with just this information, you can cross reference what you need to know about the axle.

The last set of digits on the top row on the right side is the date code.

The bottom line begins with the ratio being the first set of numbers. If an L is included, it was equipped with a limited-slip differential or Traction- Lok.

The middle number is the ring gear diameter in inches, typically an 8 or 9.

The last set of numbers is the vehicle plant code.

If the axle tag is missing, as most are, you need to remove the third member in order to know what ratio you have and if it has a limited-slip or not.

cjfisher · Jan 8, 2020

Jax,

Your rear axle is most likely a Sterling 10.5. Ford has used that axle in both single and dual wheel applications for a long time (though I think they have gone to using Dana 80s for dually applications with the 6.7 trucks and maybe even some of the late 6.4s). It is equivalent to a Dana 70. Why cry?? Your clutch looks like a single mass - if the rest of the parts are in OK shape you might see if you can have a clutch shop surface grind the flywheel. I'll bet you can save it. As much as I dislike the ratios of the ZF6 if I were in your shoes I'd keep it - it has a higher input torque capacity which will allow you to really turn the motor up. With the added power you probably won't notice the shortcomings of the ZF6. As for your post up with the clutch dedate... I switched my old 87 over to a single mass and didn't notice much of a difference. My 97 came with a Luk. With the right friction plate it is hard to notice the difference.

Cj

Jax · Jan 8, 2020

Flywheel . .

cjfisher said:
Jax,

Why cry?? Your clutch looks like a single mass - if the rest of the parts are in OK shape you might see if you can have a clutch shop surface grind the flywheel.

Cj

Thanks, CJ . . . the pressure plate is also rusty.

I thought I might get a complete kit like
https://www.southbendclutch.com/clutches/1944-6OFEK-7884/

But I am concerned because it says "Not recommended for stock applications!!"

Why would that be?

Cummins Junkie · Jan 8, 2020

Yea I certainly wouldn't worry about zf5 vs 6. It's not like you would be able to tow a bunch more with the 5...

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Jax · Jan 8, 2020

By the way, I am a spot on the map in SE AZ.

I will have to drive 100 miles to any shop.

Cummins Junkie · Jan 8, 2020

The higher hp/torque rating the clutch has, the stiffer it's going to be, and as a result, less-daily driver friendly...

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Jax · Jan 8, 2020

Thanks, CJ!

I sprayed off my transmission tag and it seems to be gone.

Is the xmsn serial number stamped anywhere?

cjfisher · Jan 8, 2020

Jax,

I'm no help on the transmission tag or serial #.. As for clutch... that clutch you linked to is a Stage 3. That is going to have a HEAVY (read - hard to push the clutch petal) pressure plate and a grippy friction plate to handle the torque and power a really souped up truck will have. That clutch is for someone really reving up and letting it out. With normal starts that stage 3 will be really jumpy. You would be better off looking at a stage one like https://www.southbendclutch.com/clutches/1944-6OK-7880/. Incidentally - I've pulled 21k (trailer + load) across town before with an old Luk clutch and a worn out friction plate so that stage 1 should pull quite a bit.

Cj

Jax · Jan 9, 2020

Thanks for the insight, CJ!

cjfisher · Jan 10, 2020

Welcome... Though I'd say there are guys on this forum that could easily run circles around my knowledge of these motors/trucks.

Cj

kenrh · Jan 10, 2020

IIRC Southbend has three stages, number 2 is what I have, good for around 400 hp over stock.
It needs their flywheel for installing.
There MAY be a version using the stock flywheel too.
The clutch requires less bedal pressure than stock too.

Touchy forum, will not allow me to post link. So to hell with them

cjfisher · Jan 10, 2020

Ken,

You need at least 10 posts... then you can add links. Or you can do something tricky like leaving spaces where the Dots should be.. When I was looking at Southbends site they have 4 levels then they jump to a level 6 which is a multi-plate competition setup.

Cj

Jax · Jan 10, 2020

Good morning, all; thank you!

The flywheel and clutch surfaces look new - no marks. Whoever let them get wet and sit should be shot!

C'est le vie . . . .

Sbluke55 · Jan 10, 2020

So your axle code is a d1 from your door sticker. That means it has a 3.73 with a limited slip. The luk clutch will be ok for stock power but I would up grade it. I had a stage 3 and it was so heavy and grabby. I now have the dual disk and love it. It’s expensive at $1350. It’s rated to 650 hp. Don’t forget to replace the clutch fork and pivot ball.

Jax · Jan 10, 2020

Clutch fork?

Sbluke55 said:
Don’t forget to replace the clutch fork and pivot ball.

Why would one want to replace the clutch fork?

Sbluke55 · Jan 10, 2020

https://www.southbendclutch.com/clutches/1944-6OK-HD-7882/

This is a great clutch too. You want an organic clutch, they are not grabby.

Jax · Jan 10, 2020

Jax' Pistons

The first piston is the piston on which the ring broke and pinged around on top.

The "cleaned" piston is the previous owner's attempt - I think he may have used a sander.

The third picture is what the rest look like. The "shiny parts" are from him drilling or milling and the particles fell into the piston box.

The block is wrapped in plastic for the trip to Tucson. There is no scoring in the cylinders, and i have not looked at the heads, yet. I expect, from my fully calibrated fingernail, that the ridge at the top of the cylinder will require it to be bored .020".

Jax' L99 F350 7.3L Truck rebuild . . . .

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