Eaton no. 4 query

Hi
We have finished the installation of the Eaton no. 4 in the old bus.

My latest issue is this. When I go from high to low ratio it seems to take a while to drop in whilst at the same time I hear a "growl" from the diff until it finally drops in. It seems to take forever but is probably around 2-3 seconds, at a guess. It doesn't seem to matter what revs I change at, it still growls at me.

I pre-select early and it doesn't seem to matter whether get off the go pedal and back on or dip the clutch.


Dropping down from high to low ratio seems to be much quicker with way less, if any, noise (unless I don't give her enough revs).

I have a solenoid to the air operated changer within about 2 feet of the unit, which pushes out approximately 100psi.

Any advice on this would be greatly appreciated.

Thanks

Ash

run an earth wire from the top of the 2speed up 2 your chassis rail it made my 2speed a lot quicker n smoother 2 change

The solenoid that sends the air to the 2 speed changer is earthed to the chassis. Do you mean to earth the diff itself to the chassis?

Hi Ashmenz0, It is fairly normal for the upshift to take longer to engage as the gears have to slowdown to allow them to lock in, whereas with the downshift you are only pulling the gears out of mesh which is virtually instantly in theory as soon as the pressure is taken off the drive. In saying this I can relate to the same slow upshift problem with a No. 4 Eaton in a Leyland Mastiff I had years ago. It had that Air shift change and one day I swapped it over for an Electric change unit out of a Commer No 4 and it worked much faster so I left it there. I dont think there is any difference between the No. 3 and No. 4 Eaton change units. If there is an Earthing problem with the Electric Unit then you can add a flexible earth lead to the Chassis as 77d5n653 described. Cheers - Kav

Hi,
Is this an upgrade or alteration??
Couple of questions come to mind here, On important one is, Do you understand how this is supposed to work??
1 Is 100 psi required to make the change, perhaps the air pack only needs half that to do the job.
2 how does the air pak dump the line pressure when you range change? ie, the air pressure between the solenoid & the air pak on the diff.
GG
A bit more info is required here

I have been told that if I had an electric changer earthing the diff to the chassis is a great help.

I don't have much experience with these diffs. I was in a friends bus with the same diff and the electric changer unit and his changed so much quicker than mine, almost without delay. I was stunned at the difference and thought it maybe due to the electric changer making the speed difference.

I may need to change to electric, although I have been told by some that the air changer is a better unit. I hope this isn't the old Ford vs Holden battle.

I wondered also whether the air ram was not pushing quick enough on the change to high ratio vs the spring snapping it back when going back to low ratio. I think I got that right ??

Hi Gilly

It is an upgrade. We took out a single speed Rockwell with the same top ratio.

I assume that the air pack would normally run on standard air pressure i.e. a bit over 100 psi for the compressor. If it was slow I thought maybe it wasn't getting enough rather than too much. Maybe I have that back to front.

The air disperses very quickly when changing back down. I can only identify this when the bus is stationary without motor running. Up & down on the button produces a quick response "clunk" from down the back end. When going down this occurs wth a short sharp blast of air escaping as well.

My understanding is that the air gets out quickly and the spring pushes back quick as well, giving a fast change on the way down. I hope I have that right?? This would mean that without air it would be stuck in low range, correct?

I've only seen the air shifts on the tandem drive diffs which are not meant to be changed on the go.
All the single drive ones I've seen have electric.
Maybe swap it over to an electric one.

Thanks fellas

My changer looks different to that one but works on the same principle.

Oil was changed when we dropped the diff in, didn't look into it too much at the time. It had an electric changer on it but the casing was smashed so the wrecker gave me the solenoid and air changer. I have added oil to the changer as well.

Swapping over to an electric will certainly tell me if it's in the diff or the changer.

Have U tried run n the gearlever thru nuetral as U change the 2 speedr
Sumtimes a grabby clutch can keep load on gears n prevent a qik change

cya