Is the 5-speed used in campers/vans like a W123 4-speed with an extra-low first? - Page 3 - PeachParts Mercedes-Benz Forum

Dr. Sternschnuppe · #31 02-13-2013, 09:47 AM

Campers/vans (I mean X07 D and X09 D models of the TN/T1 series which were equipped with OM616/617) were equipped with two types of gearbox:
with 6,15:1 first (low) gear ratio
and with 4,7:1 first (low) gear ratio

t walgamuth · #32 02-13-2013, 09:54 AM

Quote:

Originally Posted by Jooseppi Luna

...so is the TN transmission constant-mesh or sliding-gear?

Also, someone I contacted via PM raised the issue that the TN transmission was not built to handle the torque coming out of an 617.952, and would suffer premature death if mated to one. Does that sound right? I though that I remembered some camper owners upgrading to 617.952s with no reported problems. Does anyone have any thoughts one way or the other on that?

That sounds unlikely. The van/truck tranny should be a lot stronger than a car tranny.

Mölyapina · #33 02-13-2013, 09:56 AM

Quote:

Originally Posted by t walgamuth

That sounds unlikely. The van/truck tranny should be a lot stronger than a car tranny.

That's what I thought, too...

t walgamuth · #34 02-13-2013, 09:56 AM

Quote:

Originally Posted by Jooseppi Luna

So, I'm not opposed to double-clutching, but what is difference in the transmission? Why do I have a synchronized upshift but an unsynchronized downshift?

What would you say are the differences in feel from, say, a 2004 Corolla? The Corolla doesn't feel very "vague" or "notchy", it just feels average.

This thing is a 207D engine/transmission, freshly lifted out of the truck.

That's what I was thinking -- just play with a 240D shifter and keep the knob from this one.

This transmission looks longer than the four cylinder engine attached. The car four speed is nowhere that long, imho.

Really though, with the potential for distortion by cameras I'd want to see a picture of the truck and car tranny side by side.

Mölyapina · #35 02-13-2013, 10:00 AM

Quote:

Originally Posted by Dr. Sternschnuppe

Campers/vans (I mean X07 D and X09 D models of the TN/T1 series which were equipped with OM616/617) were equipped with two types of gearbox:
with 6,15:1 first (low) gear ratio
and with 4,7:1 first (low) gear ratio

Thank you ever so much! Do you know how to differentiate between the two? Different numbers? Was one installed with the 616 while the other went with 617?

Stretch · #36 02-13-2013, 12:45 PM

Quote:

Originally Posted by Jooseppi Luna

...

What would you say are the differences in feel from, say, a 2004 Corolla? The Corolla doesn't feel very "vague" or "notchy", it just feels average.

...

I've never driven a Corolla of that vintage so I can't say for sure but I get the impression that most modern Japanese vehicles of that ilk are dead boring but dead reliable. I'd expect that you'd hardly notice the shifting qualities of a Corolla - whereas for the gear boxes that you are considering I think you would!

I don't think that you are going to get a gear change - as in the actual feeling of the shift coupled with a smooth transition of power from the engine and an appropriate feeling of acceleration or deceleration of the vehicle like you get in your Corolla when you make the sort of DIY solution that you are suggesting.

Usually these types of solution are OK / great / excellent to the person who did it because they "did it" - only they are likely not to be critical about it - only they are happy to double de-clutch or ease off on the accelerator "when it does that" etc. Now there's nothing wrong with this kind of DIY modification - Renault do it all the time - but then they sell stuff to people who will put up with their **** because it is discounted and they get the feeling that they've had a good deal...

...sorry for the French car rant (!) - Basically be realistic with what you can achieve. Do some sums to see how you think the engine will cope in all gears not just the top end calculation.

Mölyapina · #37 02-13-2013, 01:31 PM

Quote:

Originally Posted by Stretch

I've never driven a Corolla of that vintage so I can't say for sure but I get the impression that most modern Japanese vehicles of that ilk are dead boring but dead reliable. I'd expect that you'd hardly notice the shifting qualities of a Corolla [You got it! That's what I was trying to communicate!] - whereas for the gear boxes that you are considering I think you would! [That's okay with me -- I like "feeling" something, which is probably why my favorite part of driving is working the clutch and double-clutching into first...]

I don't think that you are going to get a gear change - as in the actual feeling of the shift coupled with a smooth transition of power from the engine and an appropriate feeling of acceleration or deceleration of the vehicle like you get in your Corolla when you make the sort of DIY solution that you are suggesting.

[...so are you saying that the double-clutching in my Corolla is not the same as double-clutching a TN? I expect that. The Corolla is too lax on me when my double-clutch is slightly off.]

Usually these types of solution are OK / great / excellent to the person who did it because they "did it" - only they are likely not to be critical about it - only they are happy to double de-clutch or ease off on the accelerator "when it does that" etc. Now there's nothing wrong with this kind of DIY modification - Renault do it all the time - but then they sell stuff to people who will put up with their **** because it is discounted and they get the feeling that they've had a good deal...

[If you love French cars so much, why do you have a German one?

]

...sorry for the French car rant (!) - Basically be realistic with what you can achieve. Do some sums to see how you think the engine will cope in all gears not just the top end calculation.

[...working on that right now.]

Thanks for your reply! Sorry if I had trouble grasping parts of your post -- my concussion gets at me occasionally.

DeliveryValve · #38 02-13-2013, 01:36 PM

Quote:

Originally Posted by Jooseppi Luna

So, I'm not opposed to double-clutching, but what is difference in the transmission? Why do I have a synchronized upshift but an unsynchronized downshift?

.

My understanding the gears are straight cut as opposed to helical. Yet more durable, they can be noisy and downshifting a bit rough. Double-clutching on a downshift would bring the RPM on par with the gear's speed at that moment. Upshifting is not so dramatic in terms of matching the speed.

t walgamuth · #39 02-13-2013, 02:40 PM

perhaps they are straight cut on first and reverse.

Mölyapina · #40 02-13-2013, 03:01 PM

Quote:

Originally Posted by DeliveryValve

My understanding the gears are straight cut as opposed to helical. Yet more durable, they can be noisy and downshifting a bit rough. Double-clutching on a downshift would bring the RPM on par with the gear's speed at that moment. Upshifting is not so dramatic in terms of matching the speed.

Aaah, straight-cut! The reverse gear in our Corolla is straight-cut, and it's definitely louder than the forward gears. Darn. Did all the gears make the same noise, or are some of them helical-cut?

Mölyapina · #41 02-13-2013, 03:02 PM

Quote:

Originally Posted by t walgamuth

perhaps they are straight cut on first and reverse.

Well, then it would only be loud in the city...

Stretch · #42 02-13-2013, 03:09 PM

Quote:

Originally Posted by Jooseppi Luna

Aaah, straight-cut! The reverse gear in our Corolla is straight-cut, and it's definitely louder than the forward gears. Darn. Did all the gears make the same noise, or are some of them helical-cut?

Helical gears make more noise when used backwards...

...straight cut gears are stronger (well they should be!) I'd be surprised if they were fitted to any TN gear box though - as that would have made it a lot more specialised and expensive. These little commercial vehicles aren't meant to last as long as they do - they're not as well built as say a Unimog.

I could be wrong about the TN gear boxes - I'm just going on the Ford Transit ethos => build it cheap and base it on as many high volume car parts that you can.

Mölyapina · #43 02-13-2013, 03:11 PM

So it looks like a camper transmission with the 4.7:1 first gear would hit 2000 RPM at 12 MPH in first with the 2.47:1, while hitting 2000 RPM in fifth at 57 MPH (ASSUMING that 5th in the campers is 1:1). This sounds like the ideal fit! If it isn't too noisy (or if it can be silenced with sound insulation on one or both sides of the tunnel), and fits, I may start looking for a camper transmission

Oh! Would a W123 clutch fit? It would be a pain to look for a camper clutch.

Mölyapina · #44 02-13-2013, 03:22 PM

Quote:

Originally Posted by Stretch

Helical gears make more noise when used backwards...

...straight cut gears are stronger (well they should be!) I'd be surprised if they were fitted to any TN gear box though - as that would have made it a lot more specialised and expensive. These little commercial vehicles aren't meant to last as long as they do - they're not as well built as say a Unimog.

I could be wrong about the TN gear boxes - I'm just going on the Ford Transit ethos => build it cheap and base it on as many high volume car parts that you can.

Some compacts do come with straight-cut reverse gears, though -- I'll ask next time I'm at the dealer. Well, I'll see... maybe Dr. Sternschnuppe knows? I hope they're helical-cut...

t walgamuth · #45 02-13-2013, 04:12 PM

I could be wrong but I would expect straight cut gears only if no synchromesh is used. I would expect it only in a tractor or a race car.