I have a new to me early 80s IH 3500a that is giving me problems. The machine will not go up or down even small grades and when it does move it will only move in low gear with lots of throttle. The transmission is a syncromesh with a high/low selector and gear selector next to the seat. The forward/reverse is with a lever on the steering column. I am thinking it is most likely a bad clutch but wanted some advice or troubleshooting tips before I start pulling things apart. The problem seems to be worse going in reverse than forward. All the hydraulics on the machine are working fine, the machine just doesn't have any power to move. Is there anything else I should check or does this sound like a typical worn clutch? Thanks, Keith
Does it have a torch converter ?
I have a 3400a with what seems like the same problem excepting that engine RPM does not matter. When the machine is cold I can climb hills and after it gets hot I lose reverse and all hill climbing ability. My neighbour (an industrial equipment mechanic) tells me that it is the clutch. One other thing you might check is to be sure that the brakes are not hanging up.
No torque converter that I know of. It is a syncromesh transmission with a forward/reverse lever. I'm sure the brakes aren't hanging up either. You can easily feel them grab and release when you press the pedal moving in both directions. Does anyone know how the clutch engages or disengages? Is it a normal master/slave cylinder from the pedal like a car or do they use something else? I have seen posts referring to checking clutch pressure with a port on the transmission but not sure if that applies to my type of transmission or the full hydraulic transmissions that have two pedals on the floor for forward and reverse. Keith
On my machine the clutch appears to be a direct lever from the pedal. I have the floor out of mine right now and can see all the linkages from the pedal to the arm on the side of the transmission and there are no hydraulics visible. I have the same stick/ shifter configuration as you.
Somewhere on this site a guy called 'Skyking' has post regarding which clutch he used from a Napa auto parts using the Napa numbers.
A direct linkage is good. I should be able to check to make sure it isn't still holding the clutch open if I let the pedal out. Getting a new clutch isn't a problem. The clutch is common to a number of other machines. The clutch and flywheel kit is only about $350 from a number of online sources. It is all the work involved with replacing it that I want to avoid if it is something else causing the issue.
HeavyEquipmentForums Here is the link to sky king's post.
Thanks for the link. The pictures he had clearly show the manual linkage to the clutch throw out bearing. Having the transmission seal info will help if I pull the clutch out. I suspect that after 30 years replacing the seals would be a good idea no matter if they are leaking or not. Keith .
I replaced the clutch and it didn't fix the problem. Looking for what to check next. Any suggestions? Keith
I think you have a hydraulic forward and reverser. The machine has a pump mounted before the bell housing, When you split the tractor, you have to have the top cover off the trans with the linkages removed. The unit slides out from the release bearing area side, from inside the trans. It has two small clutch packs, one for the forward and one for the reverse. It could be the pump is failing or small clutch disc's are worn or failed. It is a good little bit of work to get at it. With the clutch packs not holding pressure/disc's worn, low pressure, it would not hardly pull itself. I will try to find you the test pressures and location of the test ports.
Thanks for the reply. Any help you can provide would be awesome. I have the service manual for the machine so I did a little research on the forward/reverser clutch based on your advice. Wish I had know about it when I had the motor out. Live and learn I guess. It mentions a test pot on the bottom of the transmission. Is that the port you are referring to? It also mentions a service shim pack that is available to boost the pressure if the pump is underperforming. It looks like there is some sort of spring loaded relief valve off the side of the plate the pressure port is on. If it does turn out to be the pump or the clutch pack do you know of any sources to buy the parts from? Most of the online places I have found sell the engine to transmission clutch but not the forward/reverser clutch pack. Keith
Yes on the bottom of the housing remove the plug and install a 300 psi gauge, you should be around 235-270 psi, you should be able to make some shims for the regulator if needed. Some of the parts are hard to come by also or have sub numbers that change back to caseih parts, other parts are dresser and komatsu. The biggest thing is to find a correct parts book so you have at correct part number to start with and be able to sub them up to newer numbers. Most dealers only have old micro- fiche that is worn and about unreadable. I also heard the rubber tired ih backhoe prints went to a different china/japan co. I was looking for a bearing in the old rack swing system and they had to call them for the print to see if one could be made or ordered for another member on this site. Let us know what the pressure is when you get your gauge plumbed in.
I put a gage on the port this weekend and found it was reading around 100 PSI. I'm not sure how accurate it was though since I had some leakage between the gage and the port. The gage is 1/4" NPT and the port seems to be some sort of standard thread. I was able to get a 1/4" to 1/8" NPT adaptor and the 1/8" pipe screwed into the pipe but did not seem to be exactly the right size so it leaks a bit. In either case I am no where near the 250 to 270 PSI required and it would explain the symptoms. I did pull the top plate off of the transmission to look for anything obvious but need to drain the oil to get a better look. I could see the forward/reverser clutch but don't know what looks normal. Nothing appeared broken. I plan on checking the pressure tube coming up from the pump but need to drain the fluid out first. I'm hoping to find a leak somewhere causing the issue rather than it being the pump. The service manual shows the pump as part number 587 757 R91 but a google search doesn't come up with anywhere to buy one. Keith
Did some more google searching. Found that if you left the spacing out of the part numbers it got more hits. Found that the plug for the gage is a 7/16-20 standard thread so I ordered an adaptor from MSC to be able to hook up my pressure gage without leaking. I also found the pump is still available. It is $600 which will really hurt to put into a $4000 backhoe but if it comes to that so be it. Still hoping to find a leak in the system somewhere causing the pressure drop though. I'm open to any suggestions on what to check. Keith
I did some more work on the machine last night. Got the top plate to the transmission back on and verified that the forward/reverse linkage was working right. I then put the pressure gage back on the test port with the correct adaptor to get better readings. At low idle I was at 50 psi. At full throttle I was just a little over 100. That is way below the spec of 250 to 270 at low idle. I also pulled the adjuster spring out. I was going to try some shims but the spring is so stiff I couldn't get the plug back in with it installed. I was trying to do this with fluid still in the tranny so that was some of the problem. If I could take my time without oil dumping all down my arm I'm sure it would go back together. When I started the tractor without the spring I was reading 0psi on the gage. At this point I think it is either the pump or some sort of major leak. I am going to pull the pump next but am looking for any suggestions on what to look for once it is out. Is there a way to check for a system leak beyond the pump? Any way to re-build the pump? They are still available but around $600. I don't remind replacing it as long as I can confirm that is the problem. It would not be good day to replace the pump and still have low pressure for some reason. Keith
how thick of a shim were you tryng to put in? it only takes a really thin washer or some shim stock cut to shape to see pressure differences usually.
I wasn't able to put any shims in. I wasn't even able to get just the spring back in. The fluid was pouring out of the hole when I was trying to put it back together and I couldn't push hard enough on the plug against the spring and turn it at the same time in order to get it back in place. For now I just put it back together without the spring while I figure out the next steps. I suppose I could make a tool out of an old socket to allow me to push and turn at the same time. I was planning on putting a few washers in there to try it out originally. The manual says that each shim is suppose to boost the pressure 30 to 50 psi but doesn't specify how thick the shims are. Keith
It has been a while since I posted but I am still struggling to get the machine to move. I drained the fluid, dropped the pump out the bottom of the transmission and replaced all the packings, O-rings, and plunger spring with new parts. Put it all back together and I am still getting only 50 to 100 PSI out of the test port. The pump itself looked good visually when I removed it and felt normal when turning it by hand. Not sure where to go from here. Is the pump the only possibility of being the problem? I don't completely understand how the forward/reverser clutch works. Could there be something else after the pump that would cause such a low pressure reading? Keith