2spd rear problem

[Dualie]

2SPD rear problems

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1989 F-800 ford boom truck 5spd w/ 2spd rear end 36,000 gvw. the two speed rear started acting up earlier in the weak was very touchy. Slight bump in the selector *** would send it into low range. then stopped working all together.

I know this setup uses an electric motor to shift the gears in and out. How do I go about trouble shooting this system? Is there somewhere that I can get a manual or info on this system?

This truck really is a gutless wonder it needs that two speed to be working to actually get up to highway speed. 170hp seen better days wouldn't surprise me if it was no putting less than 145hp at the flywheel.

Luckily its stuck in high range so 55 mph is actually possible for now just takes a damn while.

 

[Dualie]

Just bit the bullet and got a new switch. Still no low gear.

Local ford HD dealer wanted 48.50 for the OEM part which they did not have in stock.

Called around 3 different places that didn't have it finally got a Cole Hersee PN. 50036 for $8.69 +tax.

Replaced part and still not working. Getting a good clean signal at the rear end for high/low changes. Used a Test light on the 3 wire harness connector. Gets 12 V at the two outer pins one at a time when high and low are switched key on, engine off trans in neutral.

I can hear the motor run when the switch position is changed but there's no solid gear engagement under power. but some times makes a popping sound from the rear like it tried to go into gear when going from throttle to coasting or vice/versa

The shift Motor assembly has Eaton stamped on it.

Truck also has juice brakes. :***:

Disks in front. Drums in back. I think they might be the Lucas Girling setup. Doesn't stop well at all even with $3K+ worth of new brakes on it.

I checked googled around for a while and didn't find any info on this rear end or the 2spd assembly. Is there any where I can get a diagram and repair info for this rear end. I just need to see how this thing goes together. Just want to make sure I don't open a can of worms if I pull the cover off the shift motor.

Heres the trucks VIN. 1FDPK84P5KVA29221

Build decal on the door says:

Chassis manufactured 2/89

238" WB

Trans code: J

Rear end code: 3hp

Rear GAWR 21,000 lbs.

Front GAWR 10,860 lbs.

National crane SN/20516

 

[Jarlaxle]

1) Go to junkyard.
2) Find truck with air-brakes & 2-speed axle.
3) Swap both axles into 89.
4) Pull crane apparatus & put it on new Freightliner.
5) Sell cab & chassis to my boss cheap, since a 5+2 F-800 rollback would be a GOOD thing.

Seriously, sounds internal. Axle might be FUBARed.

 

[PackRat]

If it is sitting still, in neutral, and shifted, will it select correctly?

If the shift motor is turning and stopping, then the motor and limit switches are working correctly. Could have been as simple as an adjustment. Since it has completely stopped working, it will probably take a rebuilt pumpkin, to fix it.

They are not designed to shift under power. Most people don't shift them correctly anyhow. The correct way is to pre-select, and use the clutch to ease the drivetrain backlash. Most people just let off the throttle and bang it across. NEVER shift the 2-speed while decelerating.

 

[Dualie]

1) Go to junkyard.
2) Find truck with air-brakes & 2-speed axle.
3) Swap both axles into 89.
4) Pull crane apparatus & put it on new Freightliner.
5) Sell cab & chassis to my boss cheap, since a 5+2 F-800 rollback would be a GOOD thing.

Seriously, sounds internal. Axle might be FUBARed.

Options 1,2,3 were my first thoughts but what else would be needed? compressor, foot valve, parking valve, tanks, what else??? I would LOVE to ditch the damn juice brakes that just had $3K+ Put into them and still suck.

As for #why the hell would I disgrace my nice national crane by putting it on a freight shaker???? I would consider International or either Paccar brand preferably Pete.

And I have been known to just lift the throttle and wait for the rear to engage then back on the throttle ASAP as to not loose to much momentum going up onramps or hills. Also going from high to low when up shifting gears I just life throttle wait for RPM to drop then float next gear. Shifts way quicker that way. I HATE synchronized transmissions!!!

I did however find the repair manual on Eaton's website. So I will have to pull the shift motor and have a look see. I will call the local truck wrecker in San Jose to see what a new shift motor is going to cost.

As for #5 it would cost more to ship that pile out to where you are than it would ever be worth. But as an up side normal waste is one of my customers they can put a roll back deck on it before it gets shipped up there. But I really need to fix this pile.

I really don't have enough work for it to justify dumping that much money into it to mount it on a new chassis. I use it less than once a week. it needs to have the hydraulic fluid changed on the crane deck also.

I can select high and low and hear the motor spinning but no gear change just high range.

 

[Roland_Jenkins]

When you pull the shift motor there should be a small gear at the end of a 4 to six inch or so shaft. See if the shaft sheared off at the gear.
If so, either replace shaft and gear with new (best) or braze the gear back on. I had to do this on a ferd and it lasted for awhile.