Cat Lift Trucks (& Caterpillar) T40D:
T40D Not Going Into Forward Or Reverse

T40D Ser# 8EB12177 not going into forward or reverse. This happen all of a sudden while using it. It was working just fine before without any indication of any kind. It's engine runs great and the lift still works well. The transmission solenoids are getting power and the hand brake switch is grounded. I didn't pull apart the inching valve but there is 0 pressure or fluid at the lines going to it. I cracked them open a little to verify that. The first thing that I checked was the oil level for the transmission. It was way over filled while running. I'm coming to the conclusion that there is something wrong with the pump for the tranny. Not having a service or parts manual for this machine, I'm just winging it. Help would be appreciated. Thanks!
  • Posted 2 May 2015 08:22
  • Discussion started by FULLON
  • California, United States
Showing items 1 - 14 of 14 results.
Do you have a service manual for your forklift?
I have one which doesn't like driving forwards!
  • Posted 28 Sep 2015 04:36
  • Reply by Constablewood
  • Ayrshire, United Kingdom
ian@constablewood.com
So I flushed out the antifreeze the best I could. Interconnected the tranny cooler lines. Refilled the torque converter and tranny. Started it up but no fluid circulating. Took off the line at the inch valve that's comes from the tranny pump and filled it up with tranny fluid to try priming the pump. It started pumping fluid. Filled the tranny up more and now it drives! Drove it around a few times over the past few hours, seems to be working good. It seems to have some kind of low speed governor on it, its doesn't let the engine rev up as much when in gear. Can these be bypassed? I'm going to change the fluid again in a couple of days. I might put an external tranny cooler on it instead of pulling it all apart to fix the cooler in the radiator. Thanks again for all your help.
  • Posted 7 May 2015 08:22
  • Reply by FULLON
  • California, United States
Drained over a gallon of antifreeze out of the tranny before oil came out. Drained the torque converter of more antifreeze. I think all I can do now is try to flush out the rest of the system the best I can. Then interconnect the tranny cooler lines and not bother fixing the radiator right away and refill it with oil and hope for the best. Or is it just junk now? Thanks.
  • Posted 6 May 2015 08:50
  • Reply by FULLON
  • California, United States
Reach in right behind the left front wheel, that is the hose with the filter screen. It is within 4" of the tire. The drain plug is about 6" forward of the hose. Drain it and see what comes out. It should not be antifreeze.
  • Posted 5 May 2015 20:53
  • Reply by mrfixit
  • New York, United States
I just went out and recheck the radiator. Stuck a rag down in it and there is oil in there. So is this tranny junk now? Or do you think I should try fixing the radiator and flush the tranny out a few times? Should the tranny pump be able to pump antifreeze? Like I said nothing was coming out with the filter off.
  • Posted 5 May 2015 11:04
  • Reply by FULLON
  • California, United States
Very busy on boats today. Had a little time with the forklift. Went to pull the screen out but I think I was pulling the wrong hose off. It's on the bottom left of the tranny. Antifreeze started leaking out. There is another hose just like on the opposite side of the tranny. Is that a secondary tranny cooler???? But I did find one thing bad. I pulled of the tranny filter, there was no oil in it. But there was a little bit of antifreeze in it. When I started it, nothing came out. Maybe that's why the tranny is overfilled and not working. The cooler in the radiator is probably bad. I didn't see any oil in the radiator and it wasn't that far down on coolant. I don't think tranny's like to run on antifreeze. Going to drain the tranny tomorrow to see how much antifreeze is in it. You cant see any on the dipstick.
  • Posted 5 May 2015 10:15
  • Modified 5 May 2015 11:05 by poster
  • Reply by FULLON
  • California, United States
Pics would be great! I did get a chance to look at it yesterday for a few minutes. I did find a hose with a clamp on the left side, don't know if it's the right one. But I does go back to the pump. The hose is clamp on vertically to a fitting that goes horizontally into the tranny. I think I would have to take one of the main line to the lift pump off to get to it. Which would probably be another oily mess. I like the Idea that the tranny pump is keyed. Is the tranny pump removable from the outside? I really don't think there is any tranny oil flowing at all. Can I just take the filter off first or do I need to check the other things before that? I think you have me headed in the right direction. With your eyes on the parts and service manual it's way better than just winging it. Thanks
  • Posted 5 May 2015 00:29
  • Reply by FULLON
  • California, United States
I found I have a parts and basic maintenance manuals for that. The strainer is in the fitting with a hose clamped on it just behind the left wheel. The drain plug is just under that. If all is good with the strainer and there is no pressure coming out of the hose under the trans filter then there must be a problem with the pump or relief valve. Inside the housing that bolts to the back of the motor are gears that drive the 2 pumps. The torque convertor is a special type that the nose fits into a gear to do all that. There are sealing rings, like the ones on transmissions shafts (steel), to seal where the torque convertor fits into the main drive gear. The trans pump is keyed on to one of the shafts in there with a woodruff key. There is also a check valve with a spring and ball next to the temp sensor switch. My take is if the screen is ok, and the pressure relief is ok (there is a ball and spring and spool in there), and the check valve is ok, then the pump must have a problem. That would require taking the cover off the housing that is bolted to the motor with the torque convertor in it. Maybe try taking the filter off and starting it. If there is no sign of oil, or sound of a pump trying to do something, it's time to go in. I can sent some pics later today if you want.
  • Posted 4 May 2015 20:31
  • Reply by mrfixit
  • New York, United States
I can't go out and work on it right now. I was rope into dog sitting. I guess I'll have to drain the tranny oil since it's way overfilled before I remove the screen or I'll have a heck of a mess going on. This is one of my customers forklift. I work on his boats. He had a forklift company regularly servicing this lift. Once it stop moving, they just said it wasn't worth fixing and sold him a new one. They didn't even diagnose the problem with it. It is a Peugeot engine. It has a little over 4000 hours on it. The rest of the forklift is in great shape and was kept indoors all its life. I told him let me have a shot at fixing it before we scrap it. The lift pump and tranny pump look to be located between the engine and tranny. The lift pump runs on dextron and is right at the full mark. Maybe the lift service company overfilled the tranny? I took some photos, here is the link:


https://onedrive.live.com/?cid=2cb7147da5d82ea8&id=2CB7147DA5D82EA8%21803&Bsrc=Photomail&Bpub=SDX.Photos&sff=1&authkey=!ABVym4HM-ml0fdA
  • Posted 4 May 2015 05:23
  • Modified 4 May 2015 05:47 by poster
  • Reply by FULLON
  • California, United States
I think you will find the seal (and most likely the pump itself) to the main (lift) hydraulic pump is gone bad, on this truck (if memory serves correctly and I am getting old, but so is your forklift) the lift pump is driven off a a gear in the transmission housing. This is usually the only way you manage to 'make more oil'.
There is a 'pickup' with a filter screen, on the line at the bottom of one side of the transmission housing, that may be worth checking, you will need to remove the fitting into the transmission to find the screen, as it extends about 3 or 4 inches into the transmission..
If your truck has the Peugeot engine (that has the spark plug wires going down in the middle of the valve cover, there were more than 1 engine option for these trucks), your truck is not worth (could not be sold to a wholesaler) for what the pump costs, and may be time to consider it scrap.
  • Posted 3 May 2015 21:58
  • Modified 3 May 2015 23:20 by poster
  • Reply by edward_t
  • South Carolina, United States
"it's not rocket surgery"
The dipstick for the Tranny fluid shows it is way over filled while running. I was thinking that the pump wasn't pulling it out and all the fluid leaked back in to the reservoir. The hoses to the inching valve had no pressure what so ever or even a hint of fluid. I loosen the hoses quite a bit to where standing fluid should have leaked out.
  • Posted 3 May 2015 09:28
  • Reply by FULLON
  • California, United States
hydraulic -pressure- happens all over the circuit at the same time and equally, the -flow- may first go through the inch valve, but the -pressure- is created by a restriction later in the circuit. after the restriction, there is less -pressure-.
  • Posted 3 May 2015 09:00
  • Reply by edward_t
  • South Carolina, United States
"it's not rocket surgery"
So would that go out all of a sudden and make it have 0 pressure/fluid at the inching valve? Doesn't the pump pressurize the inching valve first? Like I said, I don't have any manuals and don't know the exact direction of the flow of the tranny fluid. I will check out the pressure relief valve tomorrow. Thanks!
  • Posted 3 May 2015 02:31
  • Reply by FULLON
  • California, United States
There is a pressure relief valve under where the trans filter mounts with the access plug facing upward that you might want to check. It has a spring and 2 spools in there.
  • Posted 2 May 2015 21:57
  • Reply by mrfixit
  • New York, United States

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