07 Rubicon Stuck in Low Gear

[07Rubicons4Life 2]

I know you're thinking this is a new guy with another 2005-2011 model year Rubicon shift issue, please go easy on me!  I just purchased a 2007 with 1,300 miles in Adventure Green that doesn't run and is missing basically all the plastics except the back fender, otherwise it's in good shape.  I'm rebuilding the carb today and also have a cheapo one that I bought from Beso's so I hope to have at least the fuel part figured out.  Tuesday I moved the gear shifter from Neutral to Drive and then to Low and now it's stuck in Low gear.  Like it won't move out of Low gear at all.  I've rocked the machine back and forth, jacked the rear end up, took the shifter itself off and nothing is obstructing it.  For some reason it is just straight up STUCK, it's acting like it's in between gears because when jack it up the rear tires will spin backwards but not forwards and when I move the linkage with a little light force the rear wheels move both forward and back.  I've spent hours and hours searching and have not seen this symptom on any forum or post so I figured I'd drop it here in the event anyone has encountered this or has any ideas.  I can't get this sucker started, and now I can't get it in neutral to even try to get it started when I slap the carb back on.  I also have a 2007 Rubicon in Camo with 1,700 miles so I know how the shifter should work, she is a beast and so I'm hoping to get this one running as well as my Camo one!

[jeepwm69 7,638]

Welcome aboard.  

 

Have you ever had this machine running?  Any evidence of anyone else being in the engine?

 

The shift shaft that is turned by the gear linkage goes through the engine from front to back, and the shift drum/ forks/ gears are behind the rear engine cover.   Point being, you can access that without having to split cases.

 

You can also pull the right brake lever and the machine should start in gear, so I'd put it up off the ground, see if it will start in gear, and see if it will shift out with the engine running.

 

Something definitely doesn't sound right, but if it won't come out of gear with working the engine while it's running, you'll probably have to pull the rear cover and see what you find.

[07Rubicons4Life 2]

I just got this machine Sunday with it being a non-running wheeler and missing all the plastics so as is, I have not been able to get it running yet.  It was only $700, and with the miles/hours worth my time as a project for my son and I to wrench on I was hoping.  All the bolts still have the factory marks on them and have not been removed across the entire machine, it's actually super clean for the year.  It wanted to run and coughed a few times like it was about to with gum cutter but I just decided to start with a carb rebuild.  Also I took off the fuel tank and flushed that out and put some fresh gas in, the petcock value is not functioning well so have another one of those coming in, also the fuel gauge must not be working because even with 1/2 a tank the light keeps blinking empty so I ordered a new one of those as well.  Threw a new spark plug in and tested that with my light it's getting spark, tested all the fuses they are good to go.  So it has spark, air, and fuel.  At this point before I spend over $1000 on body parts and all that I want to get it running and can't do that without the thing in Neutral.  I'll jack the rear up again and try turning the engine over with the front brake lever pulled and see if a couple rotations will help at all.  I read something about the shift motor going bad, could that cause this or a short?  Are their relays on this thing?  

[07Rubicons4Life 2]

Oh and it's on a trickle charger and the battery is brand new so it's not the battery.  

[jeepwm69 7,638]

3 hours ago, 07Rubicons4Life said:

I just got this machine Sunday with it being a non-running wheeler and missing all the plastics so as is, I have not been able to get it running yet.  It was only $700, and with the miles/hours worth my time as a project for my son and I to wrench on I was hoping.  All the bolts still have the factory marks on them and have not been removed across the entire machine, it's actually super clean for the year.  It wanted to run and coughed a few times like it was about to with gum cutter but I just decided to start with a carb rebuild.  Also I took off the fuel tank and flushed that out and put some fresh gas in, the petcock value is not functioning well so have another one of those coming in, also the fuel gauge must not be working because even with 1/2 a tank the light keeps blinking empty so I ordered a new one of those as well.  Threw a new spark plug in and tested that with my light it's getting spark, tested all the fuses they are good to go.  So it has spark, air, and fuel.  At this point before I spend over $1000 on body parts and all that I want to get it running and can't do that without the thing in Neutral.  I'll jack the rear up again and try turning the engine over with the front brake lever pulled and see if a couple rotations will help at all.  I read something about the shift motor going bad, could that cause this or a short?  Are their relays on this thing?  

 

Well the shifter you use on the left side of the tank shifts N, L, D, and R.  That's it.  All of those associated gears are under the rear engine cover.

 

The actual transmission on these Rubicons is a hydrostatic unit, so it runs off of oil pressure.  Yes, there is a shift motor, but all it does is move the swash plate on the hydrostatic, so what you have going on is something either in the mechanical linkage between the shift knob and the engine, or something under the rear engine cover in the shift drum and associated drive gears.

 

There are some pics in this thread.

 

Third post down shows the gears on the back of the engine.  When you shift from N to D, L, or R, that shift drum turns, and moves the shift forks, which engage the appropriate gear.

 

 

This schematic shows the shift shaft and how it engages that shift drum.

 

https://www.partzilla.com/catalog/honda/atv/2007/trx500fga-2a/gearshift-fork-gearshift-drum

 

So the shifter turns that shaft, which runs all the way through the engine and turns the drum under the rear engine cover.

 

I actually have to pull the rear cover back off of one of mine.  I went through the engine and must not have gotten something together quite right as I only have 3 gear positions and when the machine shows Neutral it tries to move forward.  I think I must have gotten a gear backwards under that back cover.  

 

But do you understand the general concept now?  You move shifter, shifter linkage turns that shaft in the schematic, which turns the shift drum on the back of the engine.  The shift drum moves the shift forks, and makes the proper gears engage each other. 

[07Rubicons4Life 2]

Thanks @jeepwm69!  This is a great start, I'm really hoping not to have to tear any further into this machine but maybe I'll just plan on pulling the back cover off tomorrow.  I tried turning the engine over with the right lever pulled and that didn't help, also with the pull cord.  I noticed that under the right brake lever two wires that hook in and one was not connected, is that a neutral safety switch or something?  I might just keep this thing jacked up on stands and try and get it running as a starting point.  I'm not too mechanically skilled just know the basics, so I'm hoping that these initial issues aren't all related and causing the thing not to even want to run. 

 

How much oil is going to leak out the back cover when I pop it off?  I guess I'm basically looking to see if the shift drum is free and not jammed up, and it's engaged in a gear (doubt I will know what gear if it is).  Does these run off oil pressure or just a straight up mechanical operation?  

[jeepwm69 7,638]

Machine runs off of oil pressure, but that hydrostat turns gears, and the gears seem to be your problem.  Before you start pulling things apart, let's check the easy stuff first.

 

And yes, you need the wires on those brake switches.  That's what allows the engine to start in gear.  It will only do so when the brake is applied.

[07Rubicons4Life 2]

So was able to get it back into neutral, just needed a tad bit more pressure at the linkage.  I was able to get it running today, well sort of it runs and sounds like absolute garbage and only with a little bit of gas applied.  Thinking maybe a stuck or burned valve?  Or maybe a blown headgasket?  This machine is just too clean, and is a Honda, I can't see how it would be something catastrophic with only 1,300 miles on it.  It wasn't knocking or smoking but did not want to run until I took a valve cover off which is why I'm thinking it was run hot and blew the headgasket.  With the valve cover off I saw that it was throwing oil so that's a good sign.  What type of lifters does this machine have, hydraulic?  

[jeepwm69 7,638]

No it has push rods.   Valves clearances might be substantially out of whack.  

 

If you have a blown headgasket you'd have milk'd oil.

 

Can you post a video of it running?   First thing I'd do is check valve clearance.  

 

You can download fhe factory service manual free in PDF format if you look at the toolbar at the top of the forum, and click on "service manuals".   It has a tremendous amount of good info/troubleshooting/instructions in it.

[ATC4ever 1,083]

I think the push rods are lifted by hydraulic lifters..but maybe i am thinking of a Harley 😆.  Def get that service manual tho for valve specs.

[shadetree 5,914]

9 hours ago, ATC4ever said:

I think the push rods are lifted by hydraulic lifters..but maybe i am thinking of a Harley 😆.  Def get that service manual tho for valve specs.

pretty sure the push rods work off the tappets that rest on the cam. no hydraulics in any honda that i know of ?.

[07Rubicons4Life 2]

Ok got back at it today. Checked compression and came back at 25 so low. Adjusted valves to .006 on intake side and .009 on exhaust side and still running rough. Took off the head to inspect the rods and both are good and nothing is loose or out of place. Got it to run again here is a video. At this point I’m thinking maybe the tensioner?  I’m going to take this as far as it leads me, so I’ll do some more research and maybe plan to take the top end off to dig some more. 

[jeepwm69 7,638]

I don't think that thing would run with compression that low.  There's a decompressor valve on the cam on most of these hondas that releases compression when cranking.  

 

You really need to do any oil pressure test.  If you read this thread of mine, oil pump chain had jumped off and starved the top end for oil.   That whole engine runs off of that oil pump, and if the oil pump chain comes off, it's affects everything. 

 

Do a little reading here.   Lots of info about the Hondamatics.  I'm trying to learn more about them, but @Brian Bertram is the expert, and he's the one selling this oil pressure tester on ebay.

 

 

 

[07Rubicons4Life 2]

It was weird in that the compression test at first showed 75, then when reset it never got above 25.  It also won't run unless one of the valve covers is off.  I read something you responded to like 12 years ago where the OP had issues that sounded very similar, and the timing had jumped one gear and after he replaced the timing chain and buttoned it all back together it was like a new machine again.  I'm going to tear the top end of this thing off tomorrow and if the timing is good then I'll probably just pull the engine from the machine and put it on the bench and go from there.  Really didn't want to get that far on a machine so clean with only 1300 miles on it, also with needing over $1,000 in body parts to put this back together after getting it running it might not be worth the total hassle.  

[jeepwm69 7,638]

9 minutes ago, 07Rubicons4Life said:

It was weird in that the compression test at first showed 75, then when reset it never got above 25.  It also won't run unless one of the valve covers is off.  I read something you responded to like 12 years ago where the OP had issues that sounded very similar, and the timing had jumped one gear and after he replaced the timing chain and buttoned it all back together it was like a new machine again.  I'm going to tear the top end of this thing off tomorrow and if the timing is good then I'll probably just pull the engine from the machine and put it on the bench and go from there.  Really didn't want to get that far on a machine so clean with only 1300 miles on it, also with needing over $1,000 in body parts to put this back together after getting it running it might not be worth the total hassle.  

 

The plastics can be had cheaper.  Look at 2014 Rubicon fenders.  Front is about $160 last time I checked.   You can also buy used flares, headlights etc.  05-11 Foreman and 05-14 Rubicon are all the same except for the left tank cover (left tank cover is cut for the shifter on the Rubicon).   That greatly opens up the used part market when searching for parts.

 

But yeah, get it running first.

 

Where are you located? 

[07Rubicons4Life 2]

I'm in Northern VA, about 30-minute drive outside DC.  I've spent easily 10 hours searching for parts for this machine for the body and actually created a spreadsheet with each part number.  It's missing so much, right now if I was to buy everything either new or used available today it would cost $1,302 to put the machine back together with fenders, splash guards, front rack, this thing doesn't even have a freaking seat.  I'm actively looking for a donor machine and on PSN/eBay and other used vendors.  I'm not buying crap for this thing not even a seat, I can use the one from my Camo machine, until it runs and rides like it should though, unless someone has a donor machine for a few hundred with good plastics.  

[07Rubicons4Life 2]

So I've read through your post two times from last year, and eyed the pictures a bunch.  Did you reuse the camshaft and tensioner on that machine?  Also, did you find that the timing was off when the oil pump chain jumped off?  

[jeepwm69 7,638]

3 hours ago, 07Rubicons4Life said:

So I've read through your post two times from last year, and eyed the pictures a bunch.  Did you reuse the camshaft and tensioner on that machine?  Also, did you find that the timing was off when the oil pump chain jumped off?  

I didn't try to start it before I tore it down.  Guy I bought it from said it didn't pull, and already had the oil tank etc removed. 

 

I did reuse the cam and tensioner.   Engine ran great after top end, rebuilt crank, new timing and oil pump chains.   That said, I either have oil pump or Hondamatic issues, because once I got good and hot (miles from home) the Hondamatic started racheting noises and didn't want to pull.  When the machine cooled down I rode it home without issues.  Luckily I had an extra engine on hand, which is my current "when I have time" project. 

 

Keep in mind that like a 2007 Rubicon rear fender might be $300, a 2014 Rubicon rear fender is $157.   Different years had different part numbers, with the difference usually only being the sticker on the fender.

 

For example, a left side cover for a 2007 Foreman was over $100.  A left side cover for a 2008 Foreman was $29.   That's what you gotta look into.  Different parts will fit your machine, and nosing around is the only way to see if a different cheaper part will fit.

2014 and 2008 Rubicon fenders etc will be the cheapest for fenders for whatever reason.

 

But yeah, let's get it running first.

 

 

[07Rubicons4Life 2]

Pulled the top end off and the timing jumped a couple teeth in the gear, surprised it actually even ran. You can see in the one pic that the exhaust valves were hitting the piston, I’ll disassemble those this week and inspect to see if they are damaged. The tensioner appears to be the issue here’s a video as well. Is the cam supposed to have that much flop and is the chain supposed to be that loose even with a bad tensioner?  For reference in the videos I had not taken the tensioner out yet. Piston clearance is nice and tight. So do I need to replace the chain and guide?  I think I might just move to correct timing and put a new tensioner on and start there. Thoughts from anyone following along?  

[shadetree 5,914]

1 hour ago, 07Rubicons4Life said:

Pulled the top end off and the timing jumped a couple teeth in the gear, surprised it actually even ran. You can see in the one pic that the exhaust valves were hitting the piston, I’ll disassemble those this week and inspect to see if they are damaged. The tensioner appears to be the issue here’s a video as well. Is the cam supposed to have that much flop and is the chain supposed to be that loose even with a bad tensioner?  For reference in the videos I had not taken the tensioner out yet. Piston clearance is nice and tight. So do I need to replace the chain and guide?  I think I might just move to correct timing and put a new tensioner on and start there. Thoughts from anyone following along?  

IMG_7531.mov IMG_7533.mov

i don't know about the piston getting damaged, but i can almost bet the valves got bent?. now that you got the head off, i would remove the valves, and have a peek to see if they got bent.

[07Rubicons4Life 2]

New tensioner comes tomorrow, got the new gasket set, Hondabond, and Honda coolant so hoping to get the machine back together tomorrow afternoon. Question: Does anyone know if there is a special way of installing this tensioner?  I've read the service manual several times and I'm not clear if I have to use some type of stopper tool to retract the tensioner before installing.  Thank you!  

[jeepwm69 7,638]

8mm cap bolt on end of tensioner. Remove it and there’s a small flathead down inside the tensioner.  Screw it all the way in (it’s under spring tension) and hold it while bolting it on, then release. 
 

IIRC there’s the old school way of checking the chain to see how badly it’s stretched  by having tensioner all the way out, and seeing how far into place you can push the tensioner. 

Remember, OEM only on timing chains.  Don’t put those aftermarket junk chains on there

 

[07Rubicons4Life 2]

Thank you for the help!  I didn't plan on replacing the chain itself at this point, I'm hoping it's the tensioner.  Once I get it installed I'll know if I have to break into this thing more.  I won't' be using anything but OEM on this project, except the seat, which I hope to get to buy before this time next year haha.  Once I get the tensioner on and test it I'll report back to close this loop.  I hope I'm replying that she's purring like a kitten!

[jeepwm69 7,638]

Definitely let us know how it goes.   Assuming you get the engine/ drivetrain right, I'll try to help you find a source for the plastic bits as cheaply as possible.

[07Rubicons4Life 2]

That would be awesome! I'm hoping that the original reason for post to the forum, difficulty shifting gears, doesn't end up being something that arises again.