1994 Ford F-350 Diesel - Transmission Problems

I remember accidentally putting the wrong computer/controller

in a V6 Dodge.Parts man missed one number.

The computer was for a V8.

When I "Finally" got it into high gear,

I was doing 85 mph at around 7-8K rpm.

Awesome! the motor seemed to run effortlessly, I felt

that I could have pegged the speedometer easily,and still be

under 25,000rpm.

Quite a remember-able experience.

Joe in Texas

You needn't baby that 7.3 let it breathe.

Upgrade to a 6-speed Allison or follow

tcmtech advice.

When you disassemble the transmission which parts are worn out? A careful failure analysis and examination of the worn parts might suggest the cause. Have you talked with mechanics at truck transmission rebuild shops and asked them to identify the cause of the problem?

I suggest there might be several problems. 1) Has the transmission case been bent or warped in some way so the gears are not in perfect alignment? 2) Is that a trouble prone transmission? Ask the dealer and check on some truck websites to inquire whether the transmission was correctly sized for that engine. Diesels produce a lot of torque and I wonder whether Ford used an older transmission that was not designed for the torque that engine produces. 2) Use a very heavy duty transmission lube that contains a great deal of zinc and other anti-wear additives. Ask the technicians at the MOBIL and Chevron websites for a recommendation because those two companies have a major commitment to lubricants.

Dennis Waller

Automatic transmissions don't require lubricants, instead high detergent value fluids are spec'd

I have a nice 5 speed in my 98 F250 that I ruined my 7.3 D within the week of a new clutch and transmission overhaul... I either need the engine you have, or you need my entire truck so you can make yours work.

Let me know...

It's been waiting to do something with it for so long I am about ready move on.

JL Mealer
http://mealercompanies.com

Hi Davnbec, I've been rebuilding these pain in the asses since they were released by Ford. I don't do as many now but still enjoy, yes enjoy, building them to keep up the skill and now rebuild them for some of my contractor friends who do not baby them, like at all!

Yes there are absolutely many things that can be done internally that will provide some longevity. Yes some electronic "interceptors" as we called them are good, however I personally haven't experienced any of recent, especially for the price, that work as well as one that was offered from 96 to 99. Unfortunately I haven't seen any on the market since. Most now only work just "ok" for TCC. But you can only go so far with that anyway.

The first decent up grade is the Art Carr VB reprogramming kit and Trans-go make a decent one as well. (I might ad, they REALLY must be installed correctly and their kit includes modifications to internal parts to truly get the desired effects and the overall efficiency increase they were designed for.) They are designed for over all operating efficiency and fixing the haunting problems related to the torque converter lockup, or TCC. There are pump up grades and I have a couple of my own "tricks" that I utilize that help with particular componants. Chamfering area of the planets and on the sun gear are just two of 7 manual upgrades I do for better oiling and or to address strength issues. Line pressure drops are common but due to a number of VB problems, oil density issues, heat of course, tolerance problems in the drum bushings, clutch pack set ups, (the center support in the old days was a bushing type that went out constantly, then they when to what is now a bearing type, it still fails and is always typical to one of the main causes of this transmissions failure) not to mention the case can warp. They used and still do sell an after market VB case-to-plate gasket that's .20 thick just to try and take up the slack. That's after the recommended, taking a hand honing stone to the surface of the case VB channeling. Clutch pack set up is critical in the fwd and intermediate drum along with utilizing of Kolene steels and Alto Reds or Borg Warner performance clutches. There are some snap ring up grades as well as torrington bearing replacements. Sonnx makes some great VB valves that hold up to replace where the bores ware out in the aluminum valve body bores which create major pressure losses. The transmission fails due to pressure losses that can occur in many areas, including the inevitable slow leaks from areas like primarily the shifter lever seal. They did well with the pan gasket they utilize. I can go on and on.

Transtar and Sonnax are just two companies I use for hard parts related to drums, planets and upgraded components that should be replaced to make those units hold up to the torque of the diesels and the load demands we put on them. Most ALL of my past customers would over load these trucks then proceed to climb up grades doubling or tripling load weight! (we have steep mountains here) Hmm, why do they not last? Because the cases are so long anytime a vibration is created due to drive line twisting, or bad U-joints, it will cause problems typically faster than most other AT's.

Utilizing good oil and maintaining proper heating or cooling to the oil is critical. For us in the southwest heat is our enemy during the summer. So, to some small degree, yes electronics can be a problem but referencing ATRA's sight (you have to be a member) and national failier accounting history of this unit, it's primarily been internal componant failier. Some due to abuse or mis-use but primarily interal componant failier due to internal pressure losses. Hope that gave you a little more insight to this jewl of a transmission. I will say with all the right up grades it's a pretty hardy transmission. What I see these guy's haul for well over a hundred thousand miles before a rebuild amazes me.