1986-ish 8400 gearco transmission no reverse

[Chillin' Champion]

Hello all. Recently picked up a 1986-ish Champion 730A with the gearco 8400 transmission. The issue I'm having is no reverse. It drives forward and seems to shift ok, (I only tried up to 3rd I thin, due to lack of turn around room), but I couldn't get it to move it any gear I tried in reverse. It seems to want to, but won't actually move the machine. Is there anyone out there that could share a manual for troubleshooting the tranmission? It looks like there are some 4 wire solenoids and some 2 wire ones? Any help would be greatly appreciated!
Thanks.

 

[James Sorochan]

Maybe put up the serial numbers and hours on machine for the grader experts to see. My 710 A sometimes won't go into reverse after sitting for awhile. I just play with the forward and reverse shifter a bit and it starts to work again. I think someone said you have to have fully charged batteries as the solenoids can have issues with low voltage. Maybe just broken wire to solenoid. See what others have to say here.

 

[Welder Dave]

Make sure you have at least 13.5 volts when running, closer to 14 is better. I had a bad connection on one of the larger wires on the starter. Fixed that and gained about a volt and a half (just under 14 on the dash gauge). If possible look real close and see if you can see a code on the gear selector screen. I have 86 730A. It acts up sometimes but won't go in either direction. At first I played with the controller but then looking close could faintly see a code but couldn't tell exactly what code. After a short period it showed the gear selected and then it worked. I've also had where it wouldn't want to reverse. Usually when there is a lump or pile of dirt behind the front wheels. I make sure to downshift all the the way to 1st gear and then it moves. There's a bunch of info in the archives on here. The solenoids on the transmission can be switched around.

 

[Chillin' Champion]

Thanks for the responses guys. First off, I can't seem to locate a serial number on the machine for the life of me. I've looked all around the cab and main frame with no luck so far. Any specific suggestions would be appreciate! The serial number on the transmission is 29781496. As stated earlier, it is a gearco 8400. Yesterday, I drained the transmission, and changed/cut the filter. There was nothing of note in the filter and the oil looked/smelled ok. If anyone has any info on which solenoids control which clutches/directions, that would be helpful. I'm ok with plumbing in some gauges, just am looking for info on where, and what I should be looking for. It does go into reverse, just "soft" and has no power, like it is slipping, or not fully engaging. Maybe a sticking spool somewhere? I will check the voltage but I would think that the machine voltage would be good as it goes into forward with a definite "clunk".

 

[Welder Dave]

Serial plate should be on right side of frame at the bottom of the bend infront of cab. Look up Sierra Park Champion 730A on the net. There's most of the basic manuals listed there. There are also seperate more involved manuals for the transmission and electronics. There's also some info on here if you use the search function. Each gear needs 3 solenoids engaged. I think someone mentioned the solenoids can be taken apart and cleaned. Best to measure actual voltage instead of guessing. It has been posted it is very critical. Also check grounds you can find and wiring connections.

 

[Chillin' Champion]

Thanks Dave. When you say the "bend" are you talking about the start of the goose neck? Or the plate below the cab door that the wing attaches to?. I just can't find any plate or stamping in the frame there. And should it be on the vertical? or on the top or bottom?

 

[Welder Dave]

Should be easily visible if you're outside the machine looking in front of the cab on the frame. It should be riveted on, maybe yours was painted over or somebody removed it? The other side of the frame should have a lubrication chart.

 

[Chillin' Champion]

Hey Guys, Update:
-The serial plate is gone off the machine, I found where the rivets were so I'm unaware of the serial number on the unit

-symptoms for the transmission is forward gears are good, (up to third), reverse is sluggish in all speeds, as in, won't move the machine if there is the least amount of resistance. When forward is engaged, it is a very positive movement, as in, no sluggishness and wants to go immediately.
-drained fluid and cut filter, nothing of note found
-removed suction screen, small amount of various material found, nothing that I would say that would lead to belief of clutch failure or any other type of bearing or gear failure
-replaced suction line to pump as there was spots that were rubbed pretty close to through and oil seemed to be aerating
-refilled sump with shell spirax t3 oil which carries the TO-2 spec oil still aerating
-checked pressures at reverse clutch and "D" clutch. had 145 PSI which is low, ( I believe the spec is 165-185 and not 215 -235 psi due to the 140 PSI observed, however, as I stated I don't have the machine serial # available to me to verify this. If there is a way using the transmission serial, this would be helpful)
-checked the voltage to the reverse coil and had system voltage, (12.6), I realize that this is a bit low but I also verified that the spool in the cartridge is moving freely out of, and installed in the collector housing, so I don't think that this is an issue but am willing to be wrong. I also verified that the resistance of the coil itself is within spec. 8.3 ohms
-removed and inspected the supply pressure regulator spring and it was intact, the spool looked good, but I added a couple shims to see if there was any change. After I got it back together, my pressure was 160 PSI, and was far more responsive on the gauge, but no change in reverse power
-removed and inspected the reverse shaft cover for scoring, there was a bit of wear, but the fact that my supply pressure isn't low at that clutch comparative to the other clutches would tell me that I'm not dealing with a leakage issue? Also inspected the hook rings on the end of the shaft and they appeared good, no cracks or chips that I could see.

-I'm at a bit of a loss as to where to go next. I don't mind pulling the trans but just don't see any evidence traditionally associated with a clutch failure. Is there a piston seal internally that could be at fault? How would I check this?
Any help would be appreciated.
Thanks!

 

[Chillin' Champion]

Anybody out there know any shops that deal with gearco transmissions? Just trying to determine if there are any other steps to try before pulling the trans out. And then wondering where to send it.

 

[bccat]

Anybody out there know any shops that deal with gearco transmissions? Just trying to determine if there are any other steps to try before pulling the trans out. And then wondering where to send it.

Do you have a shop manual?. There’s a few on the Internet . If you handy with tools, which I think you are. Get a manual and all the spec,s & rebuild it yourself. Main thing is take your time, cleanliness & pay attention to how it comes apart.Keep clutches all in order and in separate bins . Probably the clutch piston o rings have gotten hard over time, or gotten hot. Prefer power shift transmission rebuilding over manual ones. I just typed gearco 8400 on my browser got lot’s of info.

 

[Chillin' Champion]

Thanks bccat. I would definitely try the job myself. I guess my fear is that I pull it apart and then don’t find anything visually wrong. What doesn’t make sense to me is how I could have an application seal leaking and wouldn’t see it as a lower pressure than the other clutches. But I’m not completely familiar with the oil path through the shaft. And I’m the same vein, if a clutch was smoked, I would have expected to see some clutch material in the suction screen or filter pleats. Just don’t want to miss something obvious.

 

[Acecadet]

This might help you out. Check out all the champion grader info on this page. Under the Shop Manual should be everything you ever wanted to know.
http://www.sierrapark.org/Equipment/Champion_730A.htm

 

[bccat]

This might help you out. Check out all the champion grader info on this page. Under the Shop Manual should be everything you ever wanted to know.
http://www.sierrapark.org/Equipment/Champion_730A.htm

Perfect, this is the info you need

 

[Welder Dave]

Jade Equipment in Edmonton and also in Ontario I think still offers rebuilt exchange transmissions. I don't know if you need a full rebuild though. They would definitely be the best place to get advice. There is some info on here in removing the trans. if you do a search. I think it involves driving the machine up on blocks to get it up a little higher.

 

[Chillin' Champion]

Thanks all. I’m going to try installing a couple shims when I get back out there to see if I can get supply pressure back up to the upper end of spec and then retest my pressures. At the very least it will determine charge pump health and then we’ll go from there. Will let you know the results.

 

[Chillin' Champion]

Hello all. Update. I shimmed the main pressure regulator and was able to achieve around 195 psi. Still no change in the symptoms, so I pulled the trans and found the reverse clutch stack has gotten hot and frictions were quite used up. My concern now is why only those ones? The other clutches all appear to be good with no discolouration and visually at lest, uniform thickness. I remember reading something about theses transmissions getting an upgrade to the frictions but now can't seem to find it. Anybody know any history around these?

 

[Welder Dave]

Apparently better friction material was used and they also switched to 10W oil instead of Dexron II. Apparently the trans. could slip with the Dexron. Just based on what my machine does, I wonder if an operator was continually trying to reverse in too high a gear when backing over a pile or up a grade that increased the resistance?

 

[Chillin' Champion]

That would be the best case scenario Dave. So the updated friction is bronze, but it says it is used with the higher pressure (215-235vs 165-185) I’m wondering if I put the bronze in, if it will slip more due to my lower pressure. Or if I should go with the original friction type and figure it’s going to be a pretty easy runner and will last the life of the machine with me. I’d like to find a shop or person that has some experience with these transmissions and get their opinion on it. Also, I can’t get the older friction disc through jade equipment, but can get them through Alto in the states. Anyone ever dealt with their stuff?

 

[Off-Grid_Grading]

Good information in this post, I am having issues with power loss at my transmission Champion 730A Series III.
Think I have it figured as the main hydraulic pump is NFG.

Is your transmission/steering ran off of the pump in the back per the manual or the main pump off of the engine?

Good resource link.
http://www.sierrapark.org/Equipment/Champion_730A.htm

 

[Chillin' Champion]

Mine is off the pump drive under the rad. Sticks out the back. I’m pretty sure it’s only for the transmission, not the steering. Picking up the new clutch discs tomorrow morning. Hopefully have it back running by Saturday night.