MogsAndDogs
Active member
Excellent video. Thank you for the detail!
Unimogadventures - Our build and travel thread
- Thread starter Iain_U1250
- Start date
Iain_U1250
Explorer
Been a couple of big weekends working on the truck. First was to take the UG3/40 tranmission out.
In order to do that, I had to take the front and rear axles off - to get enough space for the transplant.
Then to take out the UG3/100 transmission, which came out quite easily, one I got everything else out.
Next was to take out the Claas overdrive, which proved to be a lot harder than then transnission to be honest, there is not much space in a U1250 to get it out the bottom, took a lot of twisting and tilting to get it down. It is much easier to take it out the top with the cab raised.
Next to to fit the UG3/100.
First was to replace all the transmission mounts, clean up all the gunk from almost 40 years of travel. Then a wire bush and paint the chassis behind the transmission mounts.
It took about half and hour to balance the transmission on the trans jack. Then it was squeezing the transmission up into the frame, it is bigger than the old one, so took a lot of tilting, maneuvering and levering to get it into position. After about an hour or so, it was in, and then it was lining up all the bolts, mounts and then fitting the spacers. Right now the brand new UG100 /8 transmission is sitting nicely in the frame. Next weekend I'll start putting the truck back together.
In order to do that, I had to take the front and rear axles off - to get enough space for the transplant.
Then to take out the UG3/100 transmission, which came out quite easily, one I got everything else out.
Next was to take out the Claas overdrive, which proved to be a lot harder than then transnission to be honest, there is not much space in a U1250 to get it out the bottom, took a lot of twisting and tilting to get it down. It is much easier to take it out the top with the cab raised.
Next to to fit the UG3/100.
First was to replace all the transmission mounts, clean up all the gunk from almost 40 years of travel. Then a wire bush and paint the chassis behind the transmission mounts.
It took about half and hour to balance the transmission on the trans jack. Then it was squeezing the transmission up into the frame, it is bigger than the old one, so took a lot of tilting, maneuvering and levering to get it into position. After about an hour or so, it was in, and then it was lining up all the bolts, mounts and then fitting the spacers. Right now the brand new UG100 /8 transmission is sitting nicely in the frame. Next weekend I'll start putting the truck back together.
Sitec
Adventurer
Hi Ian! Looks like massive work!! How's the hand holding up? So did the new gearbox clear the floor locker? I'd not realised the Class Overdrive went between the engine and trans. So I take it you still have the original bellhousing output plate and prop shaft. Is this to give you better overall gearing, as well as saving some weight by removing the overdrive?
Iain_U1250
Explorer
HI Simon, hand survived, probably overused it a bit as was quite sore today, but it's getting better. The new gearbox was taller than the old, but it just clears, I had to push it forward when lifting in, then move it back into position. It has about 70mm of clearance, which is enough I think. 
It is a tight fit that's for sure,
As you can see the bulge on the new gearbox is quite a bit more than the old one, but the shift cylinder is now on the other side, to it gives me a bit more room.
This is the old one, I'll re-route the air lines back under the bracket like I had before.
The new transfer case has an extra sect of mounting holes, which is a lot deeper than the old on, sticks out the bottom a bit more, so will be the lowest point on the chassis. If it turns out to be a problem, it's nothing an angle grinder can' fix, but for now I'll leave it.
The new gearbox is also deeper than the old one, which was flush with the transfer case, only about 25mm or so,
Weight wise, I the new UG100 s about 40KG heavier, and the overdrive is around 60kg, so a small saving in weight.
It is a tight fit that's for sure,
As you can see the bulge on the new gearbox is quite a bit more than the old one, but the shift cylinder is now on the other side, to it gives me a bit more room.
This is the old one, I'll re-route the air lines back under the bracket like I had before.
The new transfer case has an extra sect of mounting holes, which is a lot deeper than the old on, sticks out the bottom a bit more, so will be the lowest point on the chassis. If it turns out to be a problem, it's nothing an angle grinder can' fix, but for now I'll leave it.
The new gearbox is also deeper than the old one, which was flush with the transfer case, only about 25mm or so,
Weight wise, I the new UG100 s about 40KG heavier, and the overdrive is around 60kg, so a small saving in weight.
charlieaarons
Explorer
Got any idea how much the new transmission with G20 weighs? My guess is 380-400kg.
Iain_U1250
Explorer
It is supposed to be around 360kg, but have not measured it.
Iain_U1250
Explorer
Thank Pairoa, we are both crazy, but what would the world be without the crazy people who try things. 
This. ?
On a side note, genuinely brightens my day when the email notification pops up for this thread.
Thanks Iain, keep up the good work.
Iain_U1250
Explorer
The shed is looking a bit cleaner now, the front and back axles are now on the truck. The silver trolley in the foreground is what I made to be able to move and align the axles, couldn't have done it without it. The hydraulic jacks enable me to lift the toque tubes. This made it pretty easy to line up the prop shaft and then the torque balls.
I've cleaned up all the fuel and air lines, along with the wiring. I've given it enough slack to allow for the movement of the camper and chassis, and cab and chassis.
I've decided to mount the valve block under the passenger seat. This will protect ti from heat and dirt, and give easy access as well.
Getting the rear axle in was relatively easy, only real difficult bit was aligning the panhard rod. Took a bit of jacking and moving, but I got there in the end.
I've got a bit more work to sort out the air lines and cable on the passenger side, as I need to ensure everything is clear of the exhaust.
Next weekend I'll finish up tidying this up, and get the fuel tank and side storage back on, then all going well, the truck will be ready for a test drive.
I've cleaned up all the fuel and air lines, along with the wiring. I've given it enough slack to allow for the movement of the camper and chassis, and cab and chassis.
I've decided to mount the valve block under the passenger seat. This will protect ti from heat and dirt, and give easy access as well.
Getting the rear axle in was relatively easy, only real difficult bit was aligning the panhard rod. Took a bit of jacking and moving, but I got there in the end.
I've got a bit more work to sort out the air lines and cable on the passenger side, as I need to ensure everything is clear of the exhaust.
Next weekend I'll finish up tidying this up, and get the fuel tank and side storage back on, then all going well, the truck will be ready for a test drive.
BjarniThor
New member
In order to replace (or take out for a repair) the transmission on these Unimogs, is it really neccesary to to pull out both axles ?
Iain_U1250
Explorer
On a small one like mine, I'd say yes, as the transmission needs to go come out at quite an angle, especially if you want to fit a UG100/8 which is quite a bit bigger. I know that if you have a U1700 then you can take it out by pulling back the axles/torque tubes back away from the the with a ratchet strap, then you can lower the transmission straight down.
Iain_U1250
Explorer
The truck is finally mobile again. No big crunching noises and the gearbox changes nice and smooth.
The pneumatic gear change works great. The forward/ reverse change is super quick and smooth. The High/low range takes a few seconds to change. The engraving on the buttons came out great I think.
The valve block fits great under the seat, should be nice and safe.
I kept on hitting my head on the fuel filter, so I added a bit of carpet, it worked great, I lost count of the number of time it saved me.
The shed is finally a bit cleaner. We have an a/c unit getting fitted this week, just in time for all the work to be finished. I'll fit the fuel tank and the storage locker, and the we will be off for a test drive. I have the annual roadworthy inspection in a week or so, and then hopefully we can get away for a few days.
The pneumatic gear change works great. The forward/ reverse change is super quick and smooth. The High/low range takes a few seconds to change. The engraving on the buttons came out great I think.
The valve block fits great under the seat, should be nice and safe.
I kept on hitting my head on the fuel filter, so I added a bit of carpet, it worked great, I lost count of the number of time it saved me.
The shed is finally a bit cleaner. We have an a/c unit getting fitted this week, just in time for all the work to be finished. I'll fit the fuel tank and the storage locker, and the we will be off for a test drive. I have the annual roadworthy inspection in a week or so, and then hopefully we can get away for a few days.
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