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Discussion Starter #1
We have been doing a lot of UG2/27 tranny rebuilds lately,mostly 20 speeds.This reminded me about a discussion 15 years ago. Kai Serranno and I spoke about the possibility of taking the intermediate gears from a 20 speed and tuning it into a shiftable overdrive.
We have been looking into doing some improvements on the 20 speeds to help them out w/ longevity.We are also mating the 6 speed cascade unit w/ the intermediate and crawler gears out of the 20 speed cascade boxes. After getting a good look at several units we think we can make X3 replacement gears and replace the intermediate gears w/ a 17-22% overdrive.

The problem is that this would cost a lot in R&D as well as 2 of the 3 gears would be a little complicated witch means $$$. One would also need to have a 20 speed tranny and almost all 20 speeds already have one foot in the grave due to inherent problems associated w/ the 20 speeds. You would also have to do a partial rebuild for the install.

I'm pretty confident that the gear set would easily be around $2900-$3600
not including the install.

So the question is, would anyone be seriously interested in spending the $$$?

We will put up some posts in the future addressing different trannys and the pros and cons associated w/ them as well as some VERY important preventative maintenance that no Unimog literature tells you about!

Thanks,
Jay W/ C.O.R.E.
 

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U1600AG + a LR 90
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Most of the problems you could associate with using crawler gear in high torque situations rather than just for regulation of speed also to having the wrong type of gear oil put in them or just an amount of ineptitude from drives who seldom use manual gears so perhaps lack the natural timing of e.g. lorry drivers in the USA or automotive purists who loath the devils work in automatic transmissions vs. say Europeans ware most people drive with manual gear by preference.

I bet you average European 25 year old lady car driver can stick shift better with more finesse and timing than you average American 40 year old male driver :eek:

Anyway enough of the leg pulling ;), would the route of higher ratio portals and diffs not be a better route rather than run gearbox transmission shafts etc 17 to 22% over speed along with the rest of the drive line rather than an incremental increase at the diff and at the portal, didn’t VON have portal gears made as per the same ratio as the MB high speed ones.
 

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2015 Rubicon Unlimited (Let the shame be upon me!)
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The advantage of having it on the front end is fairly clear, instead of having slow, slower, slowest and get out and walk faster; you would have progressivly over driven ranges but with the limitation that you would only even be able to go as low as your standard differential and portal ratios allow. For a blacktop and soft road truck this may be a very useful option, allowing you to keep the standard slow portal gears and still achieve highway speeds.

The combination of the three; fastest portal gears, 15.5x20 and an overdrive cascade would allow for some silly street drivability. Still slow to accelerate but could actually cruise at highway speeds.
 

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'78 Mog 416.141 DoKa
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One would also need to have a 20 speed tranny and almost all 20 speeds already have one foot in the grave due to inherent problems associated w/ the 20 speeds. You would also have to do a partial rebuild for the install.
Could you elaborate on these inherent problems ? ?
 

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Discussion Starter #5
I'll get more info later, but 2 problems are the fine particulate material from the crawler and super crawler gears working it's way into the spring cups for the synchros and the other being an undersized retaining clip for the pre stage shaft, also the driving style and poor maintenance here in the USA attributes to their early demise.

We are developing a filtration and cooling system for the G series as well. This will be a huge and badly needed addition for our highway driving style here.

I am a terrible typist,not to mention we have 15 Unimog at the shop most of them in various stages of repair/modification, so please don't get annoyed if I don't get info up here promptly.
If anyone has a lot of serious technical questions and interest, feel free to give me or Karl a call at 1-888-X-UNIMOG.
Thanx,
Jay w/ C.O.R.E.
 

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'78 Mog 416.141 DoKa
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I'm pretty confident that the gear set would easily be around $2900-$3600
not including the install.

So the question is, would anyone be seriously interested in spending the $$$?
Isn't the cost of a fast portal gearset around the same $$ ? I recall it was $4000.

A 20% overdrive WOULD be a useful thing to have, IMO. But, if it requires loosing the slow-mo capability of the 20 speed, I, at least, value that more then fast. Of course, I already HAVE the best of both worlds - a cascade box teamed with fast axles, so I'm not a potential customer...just thinkin' out loud.

I would, however, like to hear comments on this apparent cascade weakness and cures/prevention of same.

I'll get more info later, but 2 problems are the fine particulate material from the crawler and super crawler gears working it's way into the spring cups for the synchros and the other being an undersized retaining clip for the pre stage shaft, also the driving style and poor maintenance here in the USA attributes to their early demise.

We are developing a filtration and cooling system for the G series as well. This will be a huge and badly needed addition for our highway driving style here.
I know there is a separate oil drain for the cascade. Is there a separate FILL also ? Or, does gear oil make it's way from the main box into the cascade and then back ? If so, is that path externally accessible and filterable ?

I have never changed the oil in my gearbox. It was changed right before I bought the truck and only has 4000 km's on it since.
 

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Discussion Starter #7
Danger danger Will Robinson!,Your fill is ok ,but Keep your Eye out for some good Info on your tranny here.I've got 2 mechanics getting paid for nothing at the shop right now, I gotta go.

Only the intermediate gear range will change,crawlers still there.
 

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There are two drains and one fill if you've got a cascade box. There's also an oil line connecting the two halves together, so the question is that a sump pump for extra lubrication, or just to equalize the two gearboxes? It would be neat to use that fitting for a pump and cooler/filter setup.

I know there is a separate oil drain for the cascade. Is there a separate FILL also ? Or, does gear oil make it's way from the main box into the cascade and then back ? If so, is that path externally accessible and filterable ?

I have never changed the oil in my gearbox. It was changed right before I bought the truck and only has 4000 km's on it since.
 

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'78 Mog 416.141 DoKa
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There's also an oil line connecting the two halves together, so the question is that a sump pump for extra lubrication, or just to equalize the two gearboxes? It would be neat to use that fitting for a pump and cooler/filter setup.
Is that the small hardline you can see on the bottom of the transmission ?
 

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I think you are better off with changing the gears in the axles. Cheaper as well. My hub gears are only $2375 for all eight gears. Now if you want to gear down the best bet is the 16 speed out of the SEE trucks. Gives a 17% underdrive in any gear just by the flip of a switch on the shift lever. This is what I plan on running on my truck when I get it done. A final axle ratio of 4.93/1 with the SEE transmission should be the best of both worlds!
 

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I think you are better off with changing the gears in the axles. Cheaper as well. My hub gears are only $2375 for all eight gears. Now if you want to gear down the best bet is the 16 speed out of the SEE trucks. Gives a 17% underdrive in any gear just by the flip of a switch on the shift lever. This is what I plan on running on my truck when I get it done. A final axle ratio of 4.93/1 with the SEE transmission should be the best of both worlds!
I guess the question is, what's better, an underdriver or overdrive. I would think they'd be about the same.

What's the top end speed of the 16 speed SEE?
 

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Jay,

I think the question is... what will be the total cost of the overdrive installed in the trans, including installation, rebuild/repair, ect? There are only a few of us in the U.S. that are confortable with diving into the 20 speed transmission, so it is most likely not going to be a market where there will be many do-it-yourselfers purchasing the parts. If the total cost is too high, it won't be worth your R&D because the fast hub gears are cheaper, and can be installed by anyone with some patience and mechanical knowlage. There are merits to both ways, but in the end it all comes down to total cost for the purchaser.

Cheers,
Ben
 

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Discussion Starter #13
I'm pretty sure Von's personal settup is w/ a set of R&P's w/shims and misc./$ 4,465 for 2 plus hub gears$2,200 plus misc seals etc. and a good amount of labor as well for installing X6 gear sets.
One thing to think about is a tall axle ratio provides a rather tall gear spread when shifting.
I have the same ultra fast axle set in one of my 416's and I just installed a newly remaned 20 speed we just did. W// the 6 speed this thing was almost not able to get into the rough due to the very tall 1st gear yet alone tranny spread.
If you run in the intermediate set you can make up for that,but the intermediate gear is riveted and is kind of a week link when hammering through the gears. The selectable overdrive is selected for cruising along in top gear.
The newer UG2/30 tranny may have taken care of this riveted gear issue,but I haven't opened mine up to study it yet.

Ben is very correct in the install stuff though. If you are going to install the gears you would be foolish not to do the full overhaul while it's half apart.
It would be very nice ,but a little out of most old school Moggers price range.
It may not even be doable due to not enough clearance for one of the gears anyhow.
Any way keep the opinions coming.

Thanks
C.O.R.E.
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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I think you are better off with changing the gears in the axles. ..
Makes since to me, but I dont know shiat....

Von aren't you & Jay doing essentialy the same thing via a different route..... assuming Jay would discover that after upgrading tranny he would have to upgrade axle and or hub bearings too. anyway this leaves you both doing some type of upgrade to axle and tranny.

With that in mind... Von, by the time one purchases a SEE tranny and your axle upgrade... is the total cost still less than what Jay is proposing? Curious.

Anyone considered replacing mog pumpkin with Dana, chevy orr? so you have different ratios available or is converting one to Torque tube cost the pocket about same as a second Mog?
 

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'78 Mog 416.141 DoKa
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Anyone considered replacing mog pumpkin with Dana, chevy orr? so you have different ratios available or is converting one to Torque tube cost the pocket about same as a second Mog?
IMO, 406/416 Mog diffs are MUCH stronger then D60's or D80's. D80's are 'only' rated at 11K GVWR and are ground plows to boot.

Sure, you can swap R&P's easier for more speed. But, personally, I don't think anyone has any business running around in a 406 or 416 at 70+ MPH.
 

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Seems to me the hot setup would be fast r&p+fast hubs and a selectable underdrive that wasn't a crawler box (a strong underdrive) - if you had unlimited cash to burn. ;)

It seems to me you'd want to spin the engine and trans slow on the highway, so put the gearing in the hubs.

However, the other approach of keeping the ratios large (ie: stock) in the hubs and diffs might make for a more durable drivetrain. Tradeoffs all around...


I'm pretty sure Von's personal settup is w/ a set of R&P's w/shims and misc./$ 4,465 for 2 plus hub gears$2,200 plus misc seals etc. and a good amount of labor as well for installing X6 gear sets.
One thing to think about is a tall axle ratio provides a rather tall gear spread when shifting.
I have the same ultra fast axle set in one of my 416's and I just installed a newly remaned 20 speed we just did. W// the 6 speed this thing was almost not able to get into the rough due to the very tall 1st gear yet alone tranny spread.
If you run in the intermediate set you can make up for that,but the intermediate gear is riveted and is kind of a week link when hammering through the gears. The selectable overdrive is selected for cruising along in top gear.
The newer UG2/30 tranny may have taken care of this riveted gear issue,but I haven't opened mine up to study it yet.

Ben is very correct in the install stuff though. If you are going to install the gears you would be foolish not to do the full overhaul while it's half apart.
It would be very nice ,but a little out of most old school Moggers price range.
It may not even be doable due to not enough clearance for one of the gears anyhow.
Any way keep the opinions coming.

Thanks
C.O.R.E.
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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IMO, 406/416 Mog diffs are MUCH stronger then D60's or D80's. D80's are 'only' rated at 11K GVWR and are ground plows to boot....
Yes and no.... the WHOLE axle is rated at those weights and not just the pumpkin/R&P. The Pumpkin/R&P needs less strength in a Portal design cause the high forces are moved to the Portals. In a non portal axle the forces are greater in the pumpkin.

Least that's what a poster on Pirate explained in a discussion about Mog9's and Mog44's. I have nothing to verify that.
 

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'78 Mog 416.141 DoKa
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Maybe. Don't really know. I was under the impression 416 axle diameter was larger then D60 (by a good margin). I'm not sure what usually breaks in a Dana axle - I always assumed it was the axles stubs and not the R&P.

As far as 'stress' on the crawler box...how much can it see with all that gearing between it and the rear wheels ??
 

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The axle diameters on the 406/416 are all slightly different diameters. The whole "axle system" is probably stronger than a D60.

Crawler box stress comes from misusing or shock loading it.

Do these look like the kind of gears you would want to drive under a heavy varying load?



Maybe. Don't really know. I was under the impression 416 axle diameter was larger then D60 (by a good margin). I'm not sure what usually breaks in a Dana axle - I always assumed it was the axles stubs and not the R&P.

As far as 'stress' on the crawler box...how much can it see with all that gearing between it and the rear wheels ??
 
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