2002 F350 Diesel shifting hard

[jrushing]

Hi. I bought this truck about 2 months ago to tow my 5th wheel. I've only been towing the 5th wheel around town to get used to it and learn to park it (WIP...)

It wants to shift hard into the higher gears. I am getting it checked out on Monday.

the shifting problem doesn't show up much when not towing, but noticeably when towing. truck does great on the freeway when towing. FYI it's towing a 9100 dry weight 31ft 5th wheel that I thought was strong enough to tow it.
(7.3L diesel dually).

Hoping it's not going to be an expensive repair.
Anyone else have this problem?
thanks

[ajohansson]

Im assuming you have an automatic which is the 4R100 and it is the weak point on that truck. I have 2 of them (excursion and F350) My X has 225k on original tranny. My F350 blew its guts out finally and i had a john woods transmission put in. When you get a new one put in a BTS or John Woods. You chose wisely on the truck.

Remeber its a 4 speed tranny. Around town you probably arent getting past 3rd gear. You dont want to lug it which increase your exhaust has temps (EGTs)

The tranny cooler on those trucks are tiny. A common mod is to put in a tranny cooler from the 6.0 motors. Its 3 times larger. They bolt right in. You need to get a real tranny temp gauge and a exhaust gas temp gauge commonly called a pyrometer. I would not tow with out them.

And finally get over to the dieselstop or ford truck enthusiasts forums to get a good education on your 7.3 rig.

You can pm if ya want and i can share any of my 10 plus years of owning these rigs. Just as a testament i dont ever plan on getting rid of my trucks i just assume paint them and redo the interior then dick around with a modern dieselthat required def fluid. Ill say it again you chose wisely.

[jrushing]

Thanks. I'll do that!

[SmokeyWren]

Yeah, the 7.3L PowerStroke is a great engine. I put 200,000 miles on one, after a few mods to pump up the towing power and to bulletproof the 4R100 tranny.

The 7.3L engine has 230 HP standard, but it can handle up to 300 HP without reducing the longevity or reliability of the engine. I added the towing tune that claimed 80 HP, and actually resulted in about 300 HP at the rear wheels. With that mod, the tranny no longer downshifted out of OD for every little bump in the road.

But before you add horses, you must have gauges, including a tranny temp gauge and a pyrometer (gauge for exhaust gas temp or EGT). And if you want the 4R100 tranny to last, you must increase tranny cooling to be sure you never exceed 225° sump temp.

You can add gauges and tuning with one "black box", like this one:
https://store.gopowerhungry.com/en/p...tom-tunes.html

That tuner requires you to add additional pyrometer parts to make the EGT gauge work.
https://store.gopowerhungry.com/en/p...tom-tunes.html

Yes, you need the EGT gauge if you increase HP over the stock tune. The EGT redline is 1,250°, and above that you can melt stuff in the combustion chamber. The stock tune can get up to 1,250°, but more horses can cause more than 1,250°. So when towing heavy up a mountain pass or in hilly country, you have to "drive by the gauges" and don't allow more than 1,250° EGT (or 225° tranny temp). You will soon learn to feather the go pedal to maintain right about 1,200° EGT all the way up the pass.

The easiest way to increase tranny cooling is to replace the small stock oil-to-air heat exchanger (tranny cooler) with the much bigger one from a 6.0L diesel. The 6.0 tranny cooler is a bolt-on replacement for the stock cooler, using a few simple plumbing parts from the hardware store.
Trans Cooler for 2004 Ford F-250 Super Duty|5C3Z-7A095-CA : AutoNation Ford White Bear Lake | Parts & Accessories

Even if you never allow the tranny to overheat, the torque converter and tranny will need an overhaul at about 100,000 miles. On mine, I drove to northwest Arkansas and had Bryan's Truck Shop (BTS) bulletproof my tranny and torque converter. Not cheap, but Bryan guarantees his trannys for the life of the truck. Custom Built Transmissions - Brian's Truck Shop | Lead Hill, Arkansas

If you are closer to SoCal than Arkansas, then John Wood is another excellent 4R100 overhauler.
John Wood Automotive - *

[jrushing]

thanks a lot. I am going to print out your reply and bring it to a good mechanic. thanks again.
Julia

[SmokeyWren]

Originally Posted by jrushing

Hoping it's not going to be an expensive repair.

To fix only the hard-shifting problem, I suspect you need only to replace the torque converter with a premium torque converter. The torque converter that Brian includes in his BTS overhaul is the Stallion by Precision Engineering. A new Stallion will cost about three times as much as an ordinary torque converter, but it's worth it.
Stallion Torque Converters | Precision Industries

https://puredieselpower.com/ford/e4o...converter.html

Or you can buy a new Ford OEM torque converter for less than $400 from a discount Ford parts dealer:
Converter for 2002 Ford F-350 Super Duty|1C3Z-7902-CARM : AutoNation Ford White Bear Lake | Parts & Accessories

But check with an expert tranny pro before you replace the torque converter without also rebuilding the 4R100 tranny.