My daughter recently bought me an old 1993 Ford Bronco
Engine: 5.0L V8 OHV 16V
This is a project vehicle she wants me to fix up for her
Vehicle runs but tranny seems to slip. I took it to O-Reilleys as the check engine light is on it found a few issues but two worry me the most and I need help as I am a novice mechanic.


DTC 621 Shift solenoid #1 Circuit Fault
DTC 628 excessive converter clutch slippage

I looked up parts and I see Shift solenoid packs does not sure where located and not sure if have to pull tranny to replace. Not sure if second issue is directly related to first issue. Any help would be greatly appreciated.

Thank you

 

The E4OD transmission can be as fickle as a girl shopping for a prom dress. However, the fault Codes you have gotten are fairly common. Unless it has already been done recently, I would suggest automatic transmission service (fluid, filter...have the fluid evacuated rather than just drained and refilled. It gets the old stuff out of the torque converter as well). Clear the Codes after that and see what, if any, improvements there are. If the problems persist, the solenoid pack is inside the transmission and is replaced as a unit if necessary.

 

my two cents worth would be to operate the transmission mainly in drive, not overdrive, I found that my 1990 AOD works better like that. Shift to overdrive when at freeway speeds.
After AT service, maintain the fluid, the fluid should be between the holes on the dipstick when cold and off, fluid should be on the hatched area when at operating temperature and running.

 

Those tranny codes bring back memories.
I dropped the pan. Then drained the TC, it has a plug. Remove the rubber on the bottom of the bell housing, pull coil wire then bump the starter until the plug is accessible. After you drop the pan the solenoid pack can be replaced.
Loosen two bolts at the right rear of tranny and slide heat shield back and up to get to the solenoid pack connector. Be very careful to push on the tab low and pull the connector up. You will need a torque wrench in inches to replace the solenoid pack, metric socket and Torx. Replace filter and be sure old filter gasket comes out.

Did that twice, then VSS, MLPS, both connectors, pulled and tested the wiring harness, cleaned connectors under the master cylinder. Messed with it for six months.

It was the PCM. Runs like new now with only 197K miles.

Kwowing what I know now, capacitors on the PCM fail with heat and age.
Send the PCM to ECMTOGO and let them test it and repair if needed. The PCM will fail eventually even though it is usually the last to go but age is affecting our beloved Bronco electronics now. Southern heat accelerates the demise. The PCM repair was in the low two hundreds, the solenoid packs in the low three hundreds each plus fluid and filter. All DIY.

I should have said this first, the transmission will not be happy until the engine is but those codes suggest selonoid pack, wiring or PCM. Correct the codes for engine KOEO and CM also. You want it reliable for her.

 

Morning thoughts..btw, welcome to FTE, We try our best to give you accurate information.

DTC 628 excessive converter clutch slippage
Yes, mine had the exact same code and the torque converter is great now after repairing the PCM. I suggest you disregard 628 for now.
When you drop the pan clean it well and see what is around the magnet. I suggest it even if you go for the PCM test first. I think it takes around 14 qts with the TC drained as suggested.