Transmission / Shifting Issues C6 2WD E4OD on 1992 Ford F-350

The truck will drive and pull fine for weeks at a time then I have the following issues. 1. I'll drive down the road and the truck will slip out of gear and rev up. I can let off the gas so the rpms drop and it will go back in gear. 2. I'll drive down the road and the transmission doesn't completely disengage but the rpms will creep up and down, up and down. For example 70 MPH rpms will be 2300 most of the time. When this happens they will jump to 3000, stay there for a minute, then drop back down. This will repeat for a while. The next time I'm on the highway it will run fine. I have had my truck to 2 different transmission shops and they tell me the transmission is fine. Apparently it's the first year the tranmissions had computers to the codes it provides are ok or they didn't have the equipment to read them. Any thoughts?

by in Blacklick, OH on March 08, 2011
2 answers 3 comments
ANSWER by on March 08, 2011
when it neutrals out, that is a pressure issue and that is pump related. the rpm rise and fall sounds like the converter clutch kicking in and out. i think you need a more expierenced shop that can handle your issues. i believe you have an E4OD trans which is a real problematic trans and thank god they got rid of them. Roy
COMMENT by on March 08, 2011
Am I looking at a transmission rebuild/replacement or are these things a good shop can find and fix without pulling the entire thing? Ball park cost? Thanks for your help
COMMENT by on March 08, 2011
if you love your truck, ford makes a reman or new trans with a 3 yr 36k warranty which is better than a rebuild. it is pricy. the reman are about 2900 and 8 hours in labor. add about 600 more for a new but worth it. sorry, i am from pa. area and not familiar with any shops. you can check our list of supporting shops in our web site. cannot be fixed in the truck, this is a removal only. whatever you do, dont get a used unit because of the very high failure rate of the trans. Roy
ANSWER by on March 08, 2011
To clarify Roy's info - the Ford warranty is now 3 years and 100,000 miles I believe for a remanufactured unit. Yes, this is an E4OD and it does have some limited diagnostic capability, but to test it right you need to have a transmission tester that plugs into the unit, and a set of pressure gauges. You could hypothetically have a Transmission Range (TR) sensor issue, causing the unit to go into a neutral gear - these and the wiring harnesses for them can be suspect. Same thing could apply to the high and low RPM at freeway speeds. It could be seeing a deactivation of overdrive - back and forth. Hard to say. A good diagnosis is really needed. A quick opinion regarding reliability - the E4OD is basically a C6 with electronics and overdrive, which all accounted for spent about 40 years in Ford vehicles. It has the worst rap for being behind the 7.3L Power Stroke Diesel, because it was at the edge of capability for supporting the amount of torque and gross vehicle weights that the Super Duty trucks featured. I would say more than 50% of the E4OD's I have seen failed were the result of "chipping" that 7.3L engine to produce far more torque and power than that transmission was ever built for. True, it was at the limit to begin with, but when the performance of the engine was modified, it didn't stand a chance, overheated often, and caused catastrophic failures as a result.
COMMENT by on March 09, 2011
thanks dave for catching that mileage on the warranty. Roy