'94 Bronco E4OD won't shift into 2nd

[idjeffp]

Hi All,
Was hoping someone else may have crossed this bridge already and found their way past this?

Shortly after starting, warm up and taking off, I'm finding my '94 Bronco XLT (5.8L + E4OD) won't always shift into 2nd. Usually the speedo crashes to 0 mph and the engine revs without shifting. What I've found is that if I initially rev the engine in the driveway @2K rpm for 10 - 20 s before taking off I don't have this issue. Sometimes if I'm down the road and play with shifting into 2nd then back to Drive... It engages and I get a big "slam" from the rear end and the speedo goes "Boing!" back up to speed. Was half wondering if this might be PCM related (bad e-lytic caps perhaps?) since there's a #2 Shift solenoid driven by PCM pin 19 - that I see in the manual schematics?

Reading more and seeing some TPS connection perhaps?

If this has been covered before here or elsewhere, any leads would be greatly appreciated. Searching the web as I have time... Wife and I bought this white '94 Bronco XLT new 3 days before OJ did his epic freeway run.

Thanks ahead of time!
Jeff P

 

[Tiha]

Is your speedometer working all the time?

Or does it stop working? When it is acting up?

The VSS on the rear end has a lot of control over shifting. If your speedometer is not working you should start with that.

 

[miesk5]

Yo Jeff,
Try a Self Test for Diagnostic Trouble Codes by my pal, BroncoJoe19 @ Code Reader.....
PCM stores the Self-Test program in permanent memory. When activated, Self-Test checks the EEC system by testing memory integrity and processing capability, and verifies that various sensors and actuators are connected and operating properly.

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test. Run it around to heat the engine up and shift thru all gears including Reverse. Make sure A/C is off and transmission is in Park (automatic); or in Neutral for a Manual and; release clutch. Then turn off engine, all accessories/lights (close driver's door) , etc.

Do KOEO test First. Post Code(s) here according to KOEO and KOER.

A helper can assist you by counting the codes. Some use their smart phones to record them.

BEWARE OF FAN, BELTS, PULLEYS, HOT HOSES, IGNITION HIGH TENSION WIRES, AND ENGINE COMPONENTS⚠

Or ask local mom and dad parts stores if they will test it for you.

Or purchase a coder reader such as Equus 3145 Innova OBD I Code Reader for Ford EEC IV Engines at Walmart & most parts stores.
●
TSB 94-09-12 Visor Screws

Publication Date: MAY 4, 1994

LIGHT TRUCK: 1994 BRONCO, F-150, F-250, F-350

ISSUE: The Instrument Panel Electrical PSOM (Programmable Speedometer/Odometer Module) may be inoperative or not function properly and the #8 fuse may be blown. In addition, if the vehicle is equipped with an E4OD transmission, it may exhibit a harsh shift. These conditions may be caused by trim screws installed through the 17K745 visor wire between the left hand "A" pillar and the left hand visor bullet connector.

ACTION: Tape the damaged or exposed wire conductor and add scrolling to protect the wiring from trim ***** shorts. Refer to the following service procedures for service details.

SERVICE PROCEDURE
1. Remove the garnish moulding. Refer to the 1994 Econoline, F-150-350, Bronco F-Super Duty Service Manual, Page 01-05A-5, for the removal procedure.
a. Inspect the wiring condition against the trim screws.
b.Check screws for burn marks.
2. If burn mark is found, use electrical tape to protect exposed/damaged wire. Add 1/4" (6.35 mm) scrolling to maximize protection.
3. Replace #8 fuse.
4. Reset the PSOM to see if it is functioning properly. Refer to the 1994 Econoline, F-150-350, Bronco F-Super Duty Service Manual, Page 13-01A-8, for the reset procedure.
5. Reinstall trim. Refer to the 1994 Econoline, F-150-350, Bronco F-Super Duty Service Manual, Page 01-05A-5, for the installation procedure.
6. Recheck fuse #8 and PSOM final verification.

PART NUMBER PART NAME
D4FZ-14A099-B 1/4" Scrolling (25 Ft. Roll) (100 Ft. Roll)
D6AZ-19627-A Electrical Tape
D9ZZ-14526-D Fuse
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of The Bumper To Bumper Warranty Coverage

OPERATION DESCRIPTION TIME
940912A Check And Repair Wiring 0.6 Hr.
●

E4OD
No 2nd Gear


A complaint of a 1-3 upshift (in D) is often described as a late 1-2 shift (25 mph). The most common cause is a stuck intermediate accumulator regulator valve (Fig. 1).
View attachment 217472

This is extremely common either after overhaul, or as the customer’s original complaint. On some models a trouble code 49 or 617 may be stored by the vehicle computer.
The intermediate accumulator regulator valve is extremely sensitive. Take the extra time during overhaul to thoroughly clean the valve body, flush the cooler, and on mid-91 and later units, reinstall the small spring and filter in the case (Fig. 2).
View attachment 217473



Diagnosis Tip: To help verify a stuck intermediate regulator valve, road test as follows:
With Selector in Manual Low, accelerate to 15 mph. Maintain 15 mph in Manual Low for 5 seconds, then move shifter to "2" position. A soft or weak shift into 2nd should occur. If transmission operation responds as described, a stuck intermediate accumulator valve is suspected.
The intermediate accumulator regulator valve is the small valve (and spring) held in by the retaining plate.

The location of the intermediate accumulator regulator filter and spring assembly is shown below. Only mid-91 and later units have the spring and filter assembly. Checkball locations shown are for 90-94 models Only – not 89 models.
FIGURE 2
Bulletin: #106

 

[idjeffp]

Is your speedometer working all the time?

Or does it stop working? When it is acting up?

The VSS on the rear end has a lot of control over shifting. If your speedometer is not working you should start with that.

Thanks Tiha for the reply... the speedo works normally most always, but stops working when this shift issue occurs. It goes to zero... then snaps back to speed when the slam occurs. I saw the post above and will also check for that pillar scr*w short ... and run the PCM diagnostic to check for codes.

Thanks for the leads!
Jeff P in Boise

 

[johnnyreb]

I don,t know if this can help or not--since c I have a2001 Dodge Ram (since 2002) One day I was coming back from Beckley and my radio stopped playing--air conditioner,all of the gauges---except the motor kept running. I pulled off at Arby,s near Fayettville and checked the fuses--pulling out and putting back in--didn,t see anything wrong with any of them. Got my order of food and started it back up and EVERYTHINGwas working fine and has been since----except it will add mileage up while it is parked--racked up 95 miles one night .--So you might want to check the fuses and see the tips are clean and getting a good connection. Good luck

 

[L\Bronco]

Hey Jeff:
Tiha is on the mark. The diff sensor runs both the speedo and shift timing.
They are prone to mechanical issues in the diff as well as electrical faults as well. As Miesk5 stated, try codes first and see if it has logged any vss codes.
If it did, check the wires at the vss plug on the diff. (They tend to break inside the insulation.) Also look on the left side where the harness passes the left rear shock, the harness sometimes rubs through and damages the VSS wires.
If there are no codes, pull the sensor out of the diff and look for metal filings on the sensor, plus look in the hole and make sure the reluctor wheel is still firmly attached to the diff case inside.
Hope that helps
Cheers

 

[L\Bronco]

Thanks for the leads!
Jeff P in Boise

Funny thing,
I was just in Boise Aug 5&6th for the nightfire at Firebird raceway.
Small world.
Good luck with your shift issue, keep us posted.
Cheers

 

[idjeffp]

L\Bronco would have been fun to meet up!

So is this sensor something like this one?
diff speed sensor kit

There's another issue with the rear axle rocking on acceleration / deceleration as well... probably the cause of this connector / sensor cable issue. Need to check the axle mounting bolts / nuts to see if that's the source? Probably be this weekend before I can get underneath and take a look around. Last mechanic had it up on the rack and said he thought is was a weak spring issue. trying to get the Bronco in roadworthy shape to make a trip to pickup a 3000 lb metal shaper.
Thanks!

 

[L\Bronco]

L\Bronco would have been fun to meet up!

So is this sensor something like this one?
diff speed sensor kit

There's another issue with the rear axle rocking on acceleration / deceleration as well... probably the cause of this connector / sensor cable issue. Need to check the axle mounting bolts / nuts to see if that's the source? Probably be this weekend before I can get underneath and take a look around. Last mechanic had it up on the rack and said he thought is was a weak spring issue. trying to get the Bronco in roadworthy shape to make a trip to pickup a 3000 lb metal shaper.
Thanks!

That is the one, If you have banging and locking up going on back there, I would strongly suggest you pop the cover off and do an inspection. If you don't find anything, its just a diff service, no loss there.
we take the nitro funnycar to Boise (Eagle) twice a year, Ignitor in may and Nightfire in August.
Look me up next spring. This is what she looks like.
Good luck
Cheers

 

[idjeffp]

L\Bronco that's a NICE ride your "Happy Hour" - Holy Mole...I can only imagine what it's like to drive! Reminds me of my old C*X .049 powered Pinto dragster we used to run back in the '70's!

It's a clunk on the rear axle as the rotational force shifts direction between acceleration and deceleration. The diff was just serviced and the mechanic said all was well... so suspecting axle mounting hardware - or at least wanting to check that. Probably from one too many washboard road trips.

 

[L\Bronco]

L\Bronco that's a NICE ride your "Happy Hour" - Holy Mole...I can only imagine what it's like to drive! Reminds me of my old C*X .049 powered Pinto dragster we used to run back in the '70's!

It's a clunk on the rear axle as the rotational force shifts direction between acceleration and deceleration. The diff was just serviced and the mechanic said all was well... so suspecting axle mounting hardware - or at least wanting to check that. Probably from one too many washboard road trips.

Sorry I missed a couple words in the thread, makes more sense now.
They liked to break leaf springs as well as loose U bolts holding the diff down. You should see lots of witness marks if its been shifting around.
Make sure you check the slip joint in the driveshaft for binding as well. They can cause a similar symptom.

Sadly, Its not mine, I'm part of a 4 man crew that services it between rounds.
She runs 5.6 ish in a 1\4 mile at 255MPH (Not for the weak of wallet!)
I drove roundy rounds (Stock cars and late models) for 25 yrs, this is by far the coolest thing I've been part of.
Full engine overhaul every run.
The owner drives it. (I steer it to and from the strip.)
Good luck with your diff
Cheers

 

[idjeffp]

Got an INNOVA 3145 reader headed to the house... should be helpful to see what it says!

 

[idjeffp]

Hi all,

Thanks for the guidance on this won't shift into second issue... Also had harsh thump when shifting from Park into Drive.
Well a bit of detective work checking out that cable to the rear diff speed sensor showed me the problem... The Red wire was badly frayed and separated when I was looking at it. So got the Weller soldering gun out and got it spliced back together. Works like its supposed to now!
Thanks again for all the input!
Jeff P

PS: Now if I can sort out that rear axle klunk issue! Rear leaf spring U-bolts are torqued up correctly... Shop guys that had it on the rack said the axle is rotating eg. driveshaft is pitching up/down. Hear a klunk when accelerating off from a stop. Should probably post a new thread...

 

[miesk5]

Yo Jeff,
A possible issue:

Excessive Noise

Shock absorbers. Springs. Suspension components.

PERFORM Pinpoint Test E.

PINPOINT TEST E: EXCESSIVE NOISE​

E1 INSPECT SUSPENSION​

• Raise vehicle on hoist. Refer to Section 00-02.
• Inspect shock absorber mount bolts.

Are mounting bolts loose or broken?

Yes	No
TIGHTEN/REPLACE shock absorber mount bolts. REFER to Section 04-01A, Section 04-01B or Section 04-02.	GO to E2.

E2 INSPECT SPRINGS​

• With vehicle on hoist, inspect springs for damage.

Are springs damaged?

Yes	No
REPLACE springs. REFER to Section 04-01A, Section 04-01B or Section 04-02.	GO to E3.

E3 INSPECT FRONT SUSPENSION​

• Inspect front suspension components for excessive wear or damage.

Are front suspension components worn or damaged?

Yes	No
REPLACE front suspension components. REFER to Section 04-01A or Section 04-01B.	Vehicle OK.

 

[L\Bronco]

Glad you got the VSS sorted.
That band/ cluck on accell is often a binding slip yoke at the front of the driveshaft. They make a special teflon based grease to stop the clunk.
Cheers

 

[idjeffp]

I've recently gone through the suspension components - 6 new Bilstein HD's front and rear, R/R radius arm bushings. Checked the rear spring u-bolts and they're torqued correctly. I will get under the rear axle again and take another look around and see if I can move anything. Didn't see anything last time - no rub marks... etc.