Hoping to get some technical advice here, especially from Mark but all comments welcome! Sorry for the long post. I have a 2000 f-250 diesel 4x4 (has it for about a year from PO) with a stock reman 4r100 with approximately 60k miles on it and the 7.3L rebuilt engine, bored .030 over, Chipped, pedestal turbo that can do 30lbs of boost. I have an aftermarket gauge pod showing Boost, EGT, and transmission temp, highest I’ve seen was 185 on the transmission. No idea if the TC is billet or multi-disk, my guess is that it’s bone stock (I know, not a good combo). I decided it was time for a tranny flush and some upgrades for towing to keep it cool. After getting a fluid flush at Jiffy Lube with synthetic multi vehicle aft I drove it about 5 miles home with everything operating normally. I then dropped the pan, changed the internal filter, added a bigger OTA cooler and a derale deep cooling pan, and plumbed an external filter with a pressure gauge on it. Changed out the cooler bypass tube and banjo bolts with a new unit from ford dealership just to make sure no issues. No leaks, pressure gauge in the green. I also installed new tranny cooler lines and a new radiator tranny cooler (old radiator sprung a water leak so I replaced that about a month ago). Did a flow test that passed with flying colors. Stock pan magnet had minimal material on it. I put everything back together, refilled the fluid to the correct level, and out for a test drive. The damn thing did not shift at all in drive, just stayed in 1 even close to redline rpm for a few seconds. It shifts 1-2 only in D2. In drive it feels like it’s slipping a bit at slow speeds. Once I hit the upper rpm band in d2, around 30mph, I can put it in drive and it seems to run normally in gear 4 with no slipping and normal acceleration. No clunks or abnormal sounds, temp is normal, just no shift in drive out of first gear. No tcil light flashing, speedo works fine, 4x4 works fine, even 4x4low works fine but still have the same no shift issue. I replaced the DTR sensor, reverse gear works fine and reverse lights turn on as they should, no change. I dropped the pan again and installed a brand new (not reman) shift solenoid, installed a performance reman accumulator valve body, dropped the main valve body and replaced the 1-2 shift spring with a new one (the original was not broken). Inspected all the pistons for movement and they seem fine. Lower Gasket was in great shape and all check ***** were in place. I checked the shift solenoid pigtail with a multimeter and the solenoids are getting voltage. after all that, re-installed everything and retorqued bolts to 100 in-lbs as specified in the ATSG. Refilled it and it’s STILL doing the same thing. Took it to a transmission shop in town. They hooked up a high quality reader and came up with no codes. Took it for a test drive with the code reader attached and he said everything looked to be operating normally; TSS and OSS operating normally, PCM commanding shifts normally, but it’s just not shifting in drive. He said it’s probably the sprag failed which I don’t necessarily agree with since it was fine until I dropped the pan to install a new filter and pan. I’m thinking it’s something electrical but I have no ABS light, no check engine light, nothing. I tried driving it with the alternator disconnected, no changes. Before I spend a ton of $ on a transmission drop, (if I have to drop it I’m just going to get a performance one and have the shop R&R it but I’m afraid the new transmission may not cure the problem), is there anything else I should look at? All the valve pistons in the valve bodies moved just fine. I’m going to replace the RABS sensor tomorrow (Cheap $15) and take it to autozone for an alternator test. I also have a shift solenoid replacement harness inbound (also cheap) and I plan to solder it in. The current harness and wires look ok but I’m wondering if there is a wiring issue somewhere as the truck was driven lots in the fields and mud by previous owner. I’m also going to add some additional grounds throughout the truck and check the current ground straps. I doubt that would be it since it worked just fine before the fluid/filter change. I’m at a loss at this point and trying to avoid a full transmission replacement. I appreciate any comments or advice anyone may have. Also tried driving it in all 6 chip settings, from stock to performance, still doing it.

 

Did you get a 4x4 filter for it? When you dropped the pan, how much fluid did you put back in? Are you checking the fluid level with the trans warmed up, in park, and engine idling?

 

Hi Mark, thank you for replying. I did put a 4x4 filter in it and added 7 extra quarts of fluid as called for with the derale deep pan. I checked the level when the trans was showing about 150 degrees on the gauge and it showed full.

 

Changed the Rear ABS sensor, still the same issue.

 

When you checked the level was the engine idling and the trans in park?

 

Hi Mark,
yes, engine was idling in park in a level surface. Fluid on the dipstick is at the Hot mark

 

You will need to look at what the PCM is seeing to find this problem. Get a laptop, an ELM327 adapter (available from Amazon for about $30) and Forscan (available free at www,forscan.org.) Then you can see what the PCM sees and what it commands. Then we can find out what's wrong. Or you can keep guessing at parts to change.

 

Thanks Mark, I’ll do that and report back what I find in a few days.

 

ok, I hooked up the cable to the port and my laptop with Forscan. Here are the codes it’s showing. ABS none. OBD2 none. PCM 0475 exhaust pressure control valve malfunction. Possible causes damaged PCM or damaged solenoid. PCM 0470 EBP sensor circuit malf. P0541 manifold intake air heater circuit. Possible causes short to ground harness wiring. P0640 Manifold intake air heater control circuit fault. Short to ground. No transmission specific codes

 

Ok did more troubleshooting with forscan. Also had the alternator tested, it passed. With shift selector in D, The PCM is commanding the gear change from 1 to 2 at the appropriate time, but the transmission does not shift from 1 to 2. TR 1,2,3, and 4 show open in D. In Man 2 TR 1 & 4 are open, TR 2 & 3 are closed. In man 1 tr 1 & 3 are open, 3&4 closed. TC slippage is within limits. Tranny temp is 150 degrees F. I have to move the shift lever to manual 2 for it to make the 1-2 shift. Interestingly, when I get up to about 35mph at the top end of manual 2, I can put it back in D and it drops to 4th gear immediately but I can accelerate to highway speeds. it up shifts to 3 automatically when needed. I haven’t replaced the harness pigtail yet and the shift solenoid is brand new (not a reman unit). TSS and VSS show no faults. Since the pcm is commanding the shift, it’s gotta be an issue with the harness right? Or is it the sprag that the transmission shop told me?

 

If it were a harness problem you would have a code for an electrical fault. Is that code there? If not, you can rule out the harness.

I suspect it is a bad intermediate one way clutch, also called the sprag. When you shift to manual 2 it engages the intermediate band. The band will replace the sprag for the 1-2 shift. The band is not used on automatic 1-2 shifts.

 

Thanks Mark! Guess it’s time for a new tranny...😟

 

No electrical faults.