Anybody rebuilt a G50?
Discussion
Reason for asking is the box I got last week appears to be stuck in gear. The selector moves back and forth but changes nothing. At the half travel detent it will move sideways a few degrees but not fore and aft in that plane. I removed the detent spring which allowed me to 'feel' the fore and aft travel, it is doing nothing, I cannot feel any gear clusters moving and there is no weight to it.
If I take it back I doubt the factory would take on stripping it down to find the problem so they would be stuck with a dead 'box.
I need to know what's involved to strip it and find the problem. If it's not to difficult it may be worth striking a deal with Ted and fixing it myself.
Are there loads of special tools required?
Is this a known problem?
Do springs fly everywhere when you take the housing apart?
This is a real bummer as I’ve just taken today and the last few evenings opening out the bell housing to clear the starter ring gear.
Steve. Not happy.
If I take it back I doubt the factory would take on stripping it down to find the problem so they would be stuck with a dead 'box.
I need to know what's involved to strip it and find the problem. If it's not to difficult it may be worth striking a deal with Ted and fixing it myself.
Are there loads of special tools required?
Is this a known problem?
Do springs fly everywhere when you take the housing apart?
This is a real bummer as I’ve just taken today and the last few evenings opening out the bell housing to clear the starter ring gear.
Steve. Not happy.
Hi Steve,
I remember being worried about mine - I couldn't get it to change gear either. I decided it was probably because it had no oil in it and hadn't been used for a while. I also figured I wasn't getting much leverage on the shift lever just pulling it back and fore with my hand.
It wasn't much better when it was installed as I remember, but as soon as I'd got the engine to spin it was fine. I think the first thing to do is have a chat with the factory. They'll be able to advise firstly on whether it sounds like there is a problem and secodnly what course of action to take if there is.
I know how frustrating it is when things go wrong on Saturday and you have to wait till Monday ...
Cheers,
Bob
I remember being worried about mine - I couldn't get it to change gear either. I decided it was probably because it had no oil in it and hadn't been used for a while. I also figured I wasn't getting much leverage on the shift lever just pulling it back and fore with my hand.
It wasn't much better when it was installed as I remember, but as soon as I'd got the engine to spin it was fine. I think the first thing to do is have a chat with the factory. They'll be able to advise firstly on whether it sounds like there is a problem and secodnly what course of action to take if there is.
I know how frustrating it is when things go wrong on Saturday and you have to wait till Monday ...
Cheers,
Bob
Brian Jackett said:
If its no good then shouldn't the factory supply you with a new one???
I don't think that would be a problem.
Looking at the wider picture, somewhere along the line it will need to be fixed. I don't think the factory would do that themselves so if the problem was not difficult to fix then we may be able to do a deal.
Steve
Hi Steve,
I have rebuilt a G50. Which G50 are you referring to? The one I rebuilt was the short 87'-89' model.
I would send it back to Ultima if that is where you got it from. FIrst, though, check to make sure you understand the shaft positions and what gears they correspond with. There is a difference between the older 5 speed and the 6 speed G50 models with the way they select gears. Can you select any of the gears? On my older G50, when its upside down and you are standing behind it, if you twist to the right and pull back and forth that should give you 1st and 2nd. If you twist further right, you will feel a bit of resistance. Pull back after you feel this and you will select reverse. With the shaft centered side-to-side, when you pull back and forth, this should give you 3rd and 4th. With the shaft twisted to the left, when you pull back, this should give you 5th.
You should be able to select 3rd and 4th when you pull back and push forward with the shaft centered. Do the axles turn on the box with any resistance(which would indicate that you are in gear)? You need to twist them both at the same time forward. If you feel no resistance and you don't see the input shaft spinning at the same time then your not in any gear.
To rebuild the G50 your going to need special tools. I spent around $500 U.S. on these tools. You need a tool that locks the input shaft, a large special socket that locks two large nuts on the input shaft($200 tool), and another tool that holds the input shaft in place when its out of the box. Then you'll also need an assortment of gear pullers. I can provide some photos if you like?
I had a similar story. I got my box from a reputable Porsche engine and transaxle rebuilder here in the states, and my box would not select 1st or 2nd gear. I was rather pissed, but it had been over 1-2 years from the time I ordered the box to the time I was ready to test it out. My conversation with the company wasn't too favorable, so I decided to rebuild it myself. Pulled it apart and found out that the rebuilder had used a first and second gear with a synchro hub not machined to specs' properly. The brass synchros had locked up onto the synchro hub and wouldn't twist as you tried to engage the gear. So as the input shaft was spinning, it made it impossible to select these gears.
If you don't feel any resistance as you push forward and back(with the shaft centered), then it could be that the synchros don't need to twist to engage those gears and are going in smoothly. Try twisting the two hub flanges forward a few turns and see what happens when you try to select 3rd and 4th. Also, you should feel resistance when you twist the hub flanges forward and in those gears. Also try 5th gear. Do you feel it "pop" as you twist right to select reverse? Can you pull it back afterwards into reverse? Just a few thoughts.
Cheers!
-Mack
p.s.You'll also need the factory Porsche service manual for the year of the car that your gearbox came with. I got mine on microfiche for $25 U.S., but the hardbound version is about $600.
I have rebuilt a G50. Which G50 are you referring to? The one I rebuilt was the short 87'-89' model.
I would send it back to Ultima if that is where you got it from. FIrst, though, check to make sure you understand the shaft positions and what gears they correspond with. There is a difference between the older 5 speed and the 6 speed G50 models with the way they select gears. Can you select any of the gears? On my older G50, when its upside down and you are standing behind it, if you twist to the right and pull back and forth that should give you 1st and 2nd. If you twist further right, you will feel a bit of resistance. Pull back after you feel this and you will select reverse. With the shaft centered side-to-side, when you pull back and forth, this should give you 3rd and 4th. With the shaft twisted to the left, when you pull back, this should give you 5th.
You should be able to select 3rd and 4th when you pull back and push forward with the shaft centered. Do the axles turn on the box with any resistance(which would indicate that you are in gear)? You need to twist them both at the same time forward. If you feel no resistance and you don't see the input shaft spinning at the same time then your not in any gear.
To rebuild the G50 your going to need special tools. I spent around $500 U.S. on these tools. You need a tool that locks the input shaft, a large special socket that locks two large nuts on the input shaft($200 tool), and another tool that holds the input shaft in place when its out of the box. Then you'll also need an assortment of gear pullers. I can provide some photos if you like?
I had a similar story. I got my box from a reputable Porsche engine and transaxle rebuilder here in the states, and my box would not select 1st or 2nd gear. I was rather pissed, but it had been over 1-2 years from the time I ordered the box to the time I was ready to test it out. My conversation with the company wasn't too favorable, so I decided to rebuild it myself. Pulled it apart and found out that the rebuilder had used a first and second gear with a synchro hub not machined to specs' properly. The brass synchros had locked up onto the synchro hub and wouldn't twist as you tried to engage the gear. So as the input shaft was spinning, it made it impossible to select these gears.
If you don't feel any resistance as you push forward and back(with the shaft centered), then it could be that the synchros don't need to twist to engage those gears and are going in smoothly. Try twisting the two hub flanges forward a few turns and see what happens when you try to select 3rd and 4th. Also, you should feel resistance when you twist the hub flanges forward and in those gears. Also try 5th gear. Do you feel it "pop" as you twist right to select reverse? Can you pull it back afterwards into reverse? Just a few thoughts.
Cheers!
-Mack
p.s.You'll also need the factory Porsche service manual for the year of the car that your gearbox came with. I got mine on microfiche for $25 U.S., but the hardbound version is about $600.
Been playing with it again today. If I lay the 'box on it's side I can select all gears but cannot find a neutral which would infer that one of the clusters is still engaged. If I stand it back up again it will select gears a couple of times then is back to before where it will only select back and forth but appears to remain in the one gear. The fact that it works on it’s side makes me think the fork is loose on the shaft.
Mack
Knowing how the selector is arranged can you think of a way this could happen?
It feels like the selector forks may have come loose on the shaft. Is this possible?
Can you get to just the selector forks without having to use the special tools?
Thanks
Steve
Mack
Knowing how the selector is arranged can you think of a way this could happen?
It feels like the selector forks may have come loose on the shaft. Is this possible?
Can you get to just the selector forks without having to use the special tools?
Thanks
Steve
Hi Steve, I rebuilt my G50 when the Crownwheel & Pinion broke up. You don't really need specialist tools but you will need a varied assortment of tools and the one I found most valuable is a 2 ton press.Is the gearbox jammed, as in, the mainshaft won't move or is it stuck in gear, as in, you can't deselect it?
Hi Again, I,m trying to rememember the internals of the box. (It's 18 months since I rebuilt it) If memory serves the selctor shaft that runs from the rear of the box through to the sandwich plate in the middle which supports it, off this is a selector arm which traverses the ends three other selector rods which run forward into the main casing and are attached to selector forks for 1st 2nd 3rd 4th. 5th and the reverse idler are in the rear casing.From what I remember removing the rear section is not a problem and again from what I remember nothing flew out.
If you do remove it when in the neutral position the three forks should be in line, if not, one gear is already selected, alternatively, the pin may have come out of the rear selector shaft. Good Luck!
If you do remove it when in the neutral position the three forks should be in line, if not, one gear is already selected, alternatively, the pin may have come out of the rear selector shaft. Good Luck!
Just a side note. The input shaft locking tool is pretty important. There are two very large nuts on the input shaft and one of them needs to be torqued to 180 ft.lbs. You really need that input locking tool to torque this nut that high.
Steve,
The forks slide on a set of shafts for the gears. I'll pull out my service manual and have another look, but I know there is a 1st/2nd selector shaft and a 3rd/4th selector shaft and I'll look at the manual to see what the 5th/reverse selector shaft looks like. As you pull the main selector shaft, it moves these other shafts forward and back which have the forks attached to them. These shafts have the selector fork pinned to it with a dowel pin (much like the shifter linkage). Could be that this pin has come out on one of your forks. The fork of course has a "slider" that moves back and forth and slides past the synchros and engages the gear.
I'm a little baffled by you have success when you move the box around laying it on its side or standing it on the bellhousing. This shouldn't happen. That baby should engage gears in any position. I don't think the pin came loose if this is the case. Have you tried spinning the hub flanges forward and a little and trying to select the gears? Is this a rebuilt box?
-Mack
Steve,
The forks slide on a set of shafts for the gears. I'll pull out my service manual and have another look, but I know there is a 1st/2nd selector shaft and a 3rd/4th selector shaft and I'll look at the manual to see what the 5th/reverse selector shaft looks like. As you pull the main selector shaft, it moves these other shafts forward and back which have the forks attached to them. These shafts have the selector fork pinned to it with a dowel pin (much like the shifter linkage). Could be that this pin has come out on one of your forks. The fork of course has a "slider" that moves back and forth and slides past the synchros and engages the gear.
I'm a little baffled by you have success when you move the box around laying it on its side or standing it on the bellhousing. This shouldn't happen. That baby should engage gears in any position. I don't think the pin came loose if this is the case. Have you tried spinning the hub flanges forward and a little and trying to select the gears? Is this a rebuilt box?
-Mack
Just reread your post. Don't think its the selector fork. To me it sounds like the engagement of the synchros is sticky. If its a rebuilt box, a lot of times the synchros need a little bedding in. Place the box upright (as before), and spin the hub flanges (simultaneously) forward and then try engaging the gears. If it seems to work once you do this, then I'd install the box and see what happens. Once you get the input shaft spinning from the motor, you may find its easier to select.
Cheers!
-Mack
Cheers!
-Mack
With the box in its installed position, if you can only push forward and pull back, then your telling us that you can only select either 1st/2nd or 3rd/4th. Neutral will feel sloppy and freely rotate side to side. Can you tell which it is by the position of the selector shaft? 1st/2nd, 3rd/4th, and 5th are all fairly closely positioned from either, 3rd/4th is centered and neutral is inbetween them fore/aft. Weird that you can't rotate the shaft clockwise or counterclockwise(which tells me that its either in gear or that there is something else much more significantly wrong.
I thought it might be the synchros at first, but if you can't get it into neutral then I think its something more significant. Its much easier to disengage these gears than it is to engage them (as the synchros twist to line up the guide sleeve with the gear). You shouldn't have too much diffuculty getting it into neutral. I don't think the fork has come unpinned or you'd be able to freely roatate the selector shaft. Hmh...its been a while since I looked in this box. Maybe it came unpinned with the gear engaged in 1st/2nd, 5, or reverse. Does it freely move fore and aft without much force?
Something could have been left out by accident when the box was rebuilt.
I'd talk to Ultima about tomorrow and see what they say.
I thought it might be the synchros at first, but if you can't get it into neutral then I think its something more significant. Its much easier to disengage these gears than it is to engage them (as the synchros twist to line up the guide sleeve with the gear). You shouldn't have too much diffuculty getting it into neutral. I don't think the fork has come unpinned or you'd be able to freely roatate the selector shaft. Hmh...its been a while since I looked in this box. Maybe it came unpinned with the gear engaged in 1st/2nd, 5, or reverse. Does it freely move fore and aft without much force?
Something could have been left out by accident when the box was rebuilt.
I'd talk to Ultima about tomorrow and see what they say.
Re-thinking all this info, if you can't de-select the gear at all!! Then your gear selector shaft in the rear of the gearbox is out of sync with the three forward selector shafts. i.e. it's behind them, and what you may have done is pushed it forward selected a gear but because it's not in the shaft cut out it can't pull the forward selector shaft backwards. You said that without the detent the rear selector shaft moved very freely backwards and forwards. This shouldn't happen, their should always feel some sort of interference, because if you push it back and forth irrespective of the degree it should be selecting a gear.
Rgds Ian
Rgds Ian
Mack
I think it’s sitting in the 3rd/4th but it is not moving anything, there is no load and no neutral. I don’t think it’s been opened, I imagine just pulled out of a wreck.
It’s got to be something loose or slipped or I would not get all 6 gears and reverse when it’s laying on it’s side.
Bigal1
30mm on the G50/20. Don’t see why it would be different for the /52.
Steve
I think it’s sitting in the 3rd/4th but it is not moving anything, there is no load and no neutral. I don’t think it’s been opened, I imagine just pulled out of a wreck.
It’s got to be something loose or slipped or I would not get all 6 gears and reverse when it’s laying on it’s side.
Bigal1
30mm on the G50/20. Don’t see why it would be different for the /52.
Steve
Let me look over the service manual tonight and see what kind of explanation I can come up with. Unfortunately, I've not rebuilt this thing 100 times like an experienced rebuilder so I'm just going off memmory the 2 or 3 times I've had this gearbox apart. I'm still baffled why the box operates normally on its side and not in the installed position. Very perplexing. Steve, send me your email address again so that I can send you some photos. Mine is Mack_Norris@yahoo.com
Cheers!
-Mack
Cheers!
-Mack
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