It worked yesterday an today it does not. I drove and it feels like it shifts really hard but it does not feel like it is shifting at the right time. Does the speedo/speed sensor control the shift points?

I turned the back or the speedo on the dash by hand and it appears to work/read fine, but when I try to drive it does not read anything.

I then attached the speedo cable from the transmission and turned it with a cordless. Still works/reads fine but not when connected.

I then disconnected the speedo transmission gear cluster and connected to the speedo cable and spun it with the cordless. Still works fine but does not work when I reconnect it to the transmission.

Tell me I don't have to tear the transmission down....please.

Any help is appreciated!!!!!!!!!

 

Bad gear? Remove the small bolt that holds the speedo pinion gear and pull it out. It's a plastic gear that may be bad...

 

Give us the specs on your truck. I suspect you have an E4od trans. It is controlled by the speedo. If the speedo fails or it BLOWS A FUSE the trans doesn't know how fast you are going so it will shift stupid. Check the fuses and report back.

 

Sorry, its E40D with a gas 460.

I pulled the speedo gear set out of the transmission and it looks fine and when I spin it the speedo moves but it doesn't when I reinstall it into the transmission.

The speedo has fuse????? I'll do some checking and get back with you.

 

If the speedo gear failed would the remains be in the trans pan?

 

Could it be the speedo drive gear in the trans?

How hard is it to remove?

 

What year truck do you have? I guessing you have a 89 to 91 truck as they have the speedo cable driven speedometer.


Most likely its that gear the others have said that failed.

 

That would be my guess. The wires leaving the plug on that small generator go to the computer so the computer can run the transmission right.

You will need to pull the tail housing off the transmission to replace the drive gear as it more than likely melted.

Is your 1990 F550 an RV?
Do you have an parking brake mounted on the end of the transmission?

If so the VSS is mounted in the brake housing as in the photo below.


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That's my baby, she is a 1990 Super Duty with the parking brake attached. I got the tail and parking brake assembly off but I am not sure what to do with it now. The parking brake does not want to come off the tailshaft and there is nothing in the manual that tells me what to do next. Any suggestions?

 

Did you take the six bolts out?
Removal
1. Place the transmission into gear and release the parking brake control cable. The pedal (or lever) must be in the fully released position.

2. Raise the vehicle on a twin post hoist and install safety stands.

3. On F-Super Duty Motorhome and Commercial vehicles, disconnect and remove the speedometer cable from the left hand side of the parking brake assembly.

4. Apply penetrating oil to the adjusting clevis, jam nut and the threaded end of the brake cable.

5. Loosen the jam nut and remove the locking pin from the clevis pin. Remove clevis pin, clevis, and jam nut from the brake cable. Remove cable from the bracket on the case.

6. Remove the bolts attaching the driveshaft to the parking brake assembly output flange. Remove the driveshaft and move it to one side out of the way. Wire it up to the frame.

7. Remove the six hex head bolts attaching the parking brake assembly to the transmission extension housing and remove the complete parking brake assembly from the transmission.

NOTE:
Make sure parking brake is stored with vent breather up to prevent oil leakage onto brake shoes.



Installation
1. Using two guide bolts or drift pins, attach the parking brake assembly to the transmission splined output shaft, and transmission extension housing.

2. Install six new hex head bolts to attach parking brake assembly to the transmission extension housing (Do not reuse old bolts). Tighten the bolts to 34-58N-m (25-43 ft-lbs).

3. With the parking brake assembly in the as installed position, fill the parking brake assembly with Motorcraft MERCON® Multi- Purpose Automatic Transmission Fluid XT-2-QDX or -DDX E4AZ-19582-B (ESP-M2C166-H) or equivalent to the bottom of the filler hole. Install and tighten the filler plug to 35-40 N-m (25-30 ft-lb).

4. Attach the driveshaft to the output flange, and tighten the bolts to 20-27 N-m (15-20 ft-lbs).

5. Install the parking brake cable into the mounting bracket, and snap into position.

6. Screw the jam nut and adjusting clevis onto the threaded end of the brake cable.

7. Screw the clevis clockwise (tightening) until the clevis pin can be inserted freely into the clevis and the brake actuating lever, while the lever is being held tight in the applied position, and the cable is held tight.

8. Remove the clevis pin. Rotate the clevis 10 full turns in the counterclockwise (loosening) direction (about 12.7mm [1/2 inch]).

9. Install clevis pin and locking pin.

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Thanks SubFord...thanks for all the help!!

I got the unit out but the its got like a 3" nut on one end and I've got to borrow some bigger tools.

Can I access the drive gear if I get the nut off?

 

Sorry I do not know of the nut you speak of. I am under the impression that the drive gear comes off with the brake unit along with the VSS if it is still installed.
I have the unit on my F53 but have not taken it off yet. I did work with a guy on it but he wound up just replacing the entire brake unit to fix his as a bearing locked up in his after he he had lost all of his oil.

Here is the write up he sent me, sorry I do not much more than what is in his report other than the tare down of the unit:

I had the VSS sensor gear issue, really I had an erratic speedo and a rough shifting transmission. You pointed me towards the VSS, when I pulled it I found a melted driven gear (20 tooth, black, part number CASZ-17271--B, unfortunately I was not smart enough to conclude there was a reason for the melted gear. As far as the drive gear, it is a green plastic 6 tooth worm gear part number E8TZ-2N598-A. You find many different opinions and such out there in the Ford world, there will be those who will tell you there is no plastic gear, that it is a metal gear off of the output shaft, BS, it's not the data I gave you is the straight poop, had bust my entire ZF brake assembly apart, this was on a 1996 F53 460 with an E4OD trans, 5:13 rear end. The part number stamped on the trans brake assembly is F5TD-2598-CA this is labeled as a Ford Part number. Ford however says the translated (whatever that means) is F5TZ-2598-C, there is an F5TZ-2598-A too, the difference is supposedly the A is a flat faced flange that fits certain applications, the C fits the flanged end that bolts directly to the U-Joint assembly. So Ford says the part (ZF assembly) is not rebuild-able, it is, I know, the biggest failure item in it is the bearing that is on the rear most part of the shaft, (Timken JLM 704649) The seal is numbered IPC 65-90-10 0734 310307. In my case the 4.1 ounces of Mercon trans fluid went someplace, where I don't know, there was no sigh of leakage, it was clean as a whistle on the outside, and empty on the inside. Ford wanted 2200.00 for the entire assembly, I found a place that remanufactured them for 1050.00 6 month warranty, I found a salvage one off a motorhome in Mo. for 450.00 with a 6 month warranty, I bought it, received it a few days later, it was clean, the brakes shoes were not contaminated, the VSS and gear were good, did not smell burned, filled it with the 4.1 in called for then a tad more and put it back together, so far she is working like a charm. My bearing spun in the housing so would have to have been machined and sleeved, and cost more than the salvage one.
Bill thanks for all you help and guidance, it was a godsend. Much appreciated, sorry I am so tardy in this report.

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Thanks SubFord!
I took it last night to a friend of mine who has a race car transmission shop to see if they could break it down. He said he was not real familiar with e40d but knew some of his guys at the shop were. I'll let you know what we find and how they got the assembly apart.

Thanks everyone again for your help!

What an awesome site!

 

Here is a photo of it taken apart but I do not see the drive gear for the speedometer.
I can send you a PDF of how to take it apart if you email me your email address.



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By the way if you can get any photos of the drive gear mounted on the shaft you can send them to me at the email address below.
As I would very much like to see them.
Thanks