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Cat powershift false neutral

Fellingtreez

Active Member
Joined
Apr 25, 2021
Messages
25
Location
West Virginia
I have a D4E that just had the transmission cooler replaced. The transmission feels strong but there is an issue with a false neutral from time to time.

I’ll explain.
Sometimes shifts go as normal but from time to time when I select a gear whether in forward or reverse it doesn’t engage the gear. If you shift back to neutral then to the gear you want it engages and works all speeds from that point on. It only happens when switching directions and not when changing speeds if that makes sense.

I’m curious to see if anyone had encountered this or has a lead on where to start.
 

Bluox

Senior Member
Joined
Jun 19, 2010
Messages
1,960
Location
WA state
I have a D4E that just had the transmission cooler replaced. The transmission feels strong but there is an issue with a false neutral from time to time.

I’ll explain.
Sometimes shifts go as normal but from time to time when I select a gear whether in forward or reverse it doesn’t engage the gear. If you shift back to neutral then to the gear you want it engages and works all speeds from that point on. It only happens when switching directions and not when changing speeds if that makes sense.

I’m curious to see if anyone had encountered this or has a lead on where to start.
Pull the seat up and clean the linkage out and check for wore out linkage .
Bob
 

Fellingtreez

Active Member
Joined
Apr 25, 2021
Messages
25
Location
West Virginia
I took the panels off today and noticed little slop if any in the linkages.

I reviewed the adjustment procedure and it stated at the end that all detents should be felt. I do feel all the gears and when operating half the time it goes right into gear and pulls.

In the manual it mentions finding rubber particles in the screen of the transmission being an indicator of a seal failure. And unfortunately I did find some particles.

Transmission was said to be rebuilt before I bought the machine but it has been years and it sat a while. Wonder if there could be remnants from before the rebuild.

I’m sure if it gets any worse the pressures would have to be checked. I saw where some of the ports are but don’t know if I could buy a gauge and do it myself. Is that a common diy procedure?
Can any seals be replaced or pressure leaks be fixed with the transmission in the machine?
Of course if I get lead to there...
 

Glum

Active Member
Joined
Feb 15, 2017
Messages
29
Location
South Africa
What is the trans/converter temp guage reading?
Linkages are the place to start.
Following that, gaskets on the pump suction line can create issues. So can tired o rings in the trans control valve. After that it starts to look like pressure loss in the transmission itself.
 

Fellingtreez

Active Member
Joined
Apr 25, 2021
Messages
25
Location
West Virginia
The torque converter temp is the only transmission related gauge I have on the dash. I believe.
It usually runs in the first quarter to maybe half ways. Stays well into the green from what I’ve seen.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
Did you remove & inspect the suction screens plus the condition of all the clamps, gaskets, o-rings, etc, in the powertrain oil lines suction side as far as the pump when you had the system apart for the cooler problem.? It’s not unusual for a joint or clamp to leak when things got hot if something is not 100% tight or a joint is old & cracked.

Also does your transmission control linkage have any grease zerks on the bell cranks.?
 

Fellingtreez

Active Member
Joined
Apr 25, 2021
Messages
25
Location
West Virginia
I did not notice any grease zerks on the transmission linkage. I will check again.

I had the piping from the transmission to the cooler resealed in 3 out 4 fittings. And loosened and retightened a rubber hose joint. Don’t know if that’s the suction side or not.

Replaced the seals for the oil filter canister. New gasket on the suction screen on the bottom. I assume that’s the magnetic screen. Might not be... I didn’t see any other suction screen. manual is vague at time it seems.

I did use T02 when I changed. Manual called for it but it sounds like most use T04 now. Reading slightly high on the dipstick when warm and running.

Can the O rings in the trans control valve be checked easily or is that a tough job?
 

Fellingtreez

Active Member
Joined
Apr 25, 2021
Messages
25
Location
West Virginia
How crucial is the transmission linkage adjustment?
It seems to catch the gears fine but if it would be worth my time to check adjustment I would.
Seems like things don’t move much under there to select between forward and reverse. 1-3 seems to go click right through.
 

oarwhat

Senior Member
Joined
Dec 14, 2009
Messages
824
Location
buffalo,n.y.
Not the same machine but we had the exact thing happen in an old 988A wheel loader. It had a safety valve in the transmission if you started it in gear the transmission wouldn't go into gear. You had to shift into neutral to get in gear. So it acted like yours sometimes it went in gear sometimes not. Back to neutral and it worked fine. Had a Cat mechanic check the pressures all were ok. They did drop as it went in gear which he said was normal. So I figured that drop maybe activating the safety valve putting in to neutral. The valve was spring loaded. When hydraulic pressure pushed the valve it could go into gear. So with that dip in pressure it would release and go into neutral.
So I removed the valve body and took a wild guess at a weaker spring. I got lucky no more going into neutral and it still wouldn't move if started in gear.
Now I don't know if your dozer transmission has that valve but it sure acts like mine did.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
I would suggest to get a pressure gauge hooked up to the P2 (Direction) clutch test point. Observe the reading on the gauge when the transmission is failing to shift into gear. Even better get two gauges and have one on the P1 (Speed) clutch year point as well.

Setting the control linkages starting from scratch is not difficult, although it’s a bit tedious if done right because there are lots of steps and you can’t skip any of them. It certainly wouldn’t hurt to do it. Do you have the procedure.?
 

Fellingtreez

Active Member
Joined
Apr 25, 2021
Messages
25
Location
West Virginia
Yeah I believe I do have the adjustment procedure.
What I don’t have are the proper gauges.... what exactly would I have to buy to do the pressures? Would I need two gauges to measure in the two spots at once?
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
You would need at least one gauge capable of measuring up to 500psi, or two if you decide to hook up to both P1 & P2. TBH one on P2 would probably be enough to see what’s going on.

I’ll find the adjustment procedure and post it up.
However to make sure it's the correct one will require the tractor Serial Niumber.
 
Last edited:

Glum

Active Member
Joined
Feb 15, 2017
Messages
29
Location
South Africa
How crucial is the transmission linkage adjustment?
As you noted, there is very little movement on the direction linkage, and it can give you the fits if not moving correctly. Usually though, it tends to want to make the machine move in the wrong direction to that selected.
One of mine recently kept loosing drive when turning right and turned out to be the steering linkage occasionally catching the little vertical forward/ reverse linkage just before it goes into the trans.
 

JimInOz

Senior Member
Joined
Apr 15, 2008
Messages
508
Location
Victoria, Australia
Definately go over the linkages. There can be wear on pivot arms,pins,rods...everything.Sometimes wear doesn't show until you separate the various linkage components. A few millimetres of wear at several points makes a big difference.
If nothing else is achieved,you have a starting point & can cross it off the list...
 

John C.

Senior Member
Joined
Jun 11, 2007
Messages
12,865
Location
Northwest
Occupation
Machinery & Equipment Appraiser
I've seen plenty of old Cat dozers where the transmission linkages get slapped hard all day long. With all the covers off, maybe you should slap the lever side to side and watch what happens at all the pivot points. The detents in the valve will handle a whole lot of slop in the transmission linkages.

Checking pressures is the next step. You will see pressures drop between shifts because the valves modulate the shifting to take out some of the shock of changing directions. It sounds like you might have a worn transmission pump that may be a low on flow or some worn valves that take a few extra seconds to fill a clutch pack. At this point, you can't troubleshoot anything without a gauge or two to see what is happening with the pressures. I always used 600 PSI gauges for testing transmissions.

Good Luck
 

Fellingtreez

Active Member
Joined
Apr 25, 2021
Messages
25
Location
West Virginia
I got to test the pressure today.

P2 showed right at 250psi. If my gauge was accurate.

It ran a little lower cold. 0psi in neutral.
Would jump to 250 PSI during shifts, also would spurt a small amount of fluid when you went back to neutral.
I assume that’s normal.

Made no difference in pressures in either direction or speed.

It didn’t seem to have any problems shifting today until it got good and warm then it started missing shifts, but still wasn’t as bad. Showed 0 psi when it didn’t shift.
The only thing I have changed was took one part of a linkage apart to inspect it but it seemed tight.
About it tho, it seems someone might have substituted a Allen head bolt with some shims to make it work? It seems good and tight but it’s on the direction side of the shifter and may be a problem if it isnt the factory part. I can post a pic of it later.
 
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