Is the 5-speed used in campers/vans like a W123 4-speed with an extra-low first? - Page 2 - PeachParts Mercedes-Benz Forum

47dodge · #16 02-12-2013, 06:26 PM

Really need to run the numbers. compare the total drive ratio in first with the current rear, then do the first gear ratio with the proposed tranny and lower rear and then you can see exactly what you will get. For bumper to bumper traffic it could be good. just let it idle in first and creep along.

I would expect first to be non syncro, but the rest should be syncronized. I do not know this for fact, but it is the normal way a truck tranny is done.

Mölyapina · #17 02-12-2013, 06:41 PM

Quote:

Originally Posted by 47dodge

Really need to run the numbers. compare the total drive ratio in first with the current rear, then do the first gear ratio with the proposed tranny and lower rear and then you can see exactly what you will get. For bumper to bumper traffic it could be good. just let it idle in first and creep along.

I would expect first to be non syncro, but the rest should be syncronized. I do not know this for fact, but it is the normal way a truck tranny is done.

The 1st-gear synchronizer in our Corolla is not very sharp anymore (at least, I think that's what it is), so I've been learning the basics of double-clutching. It doesn't phase me -- in fact, I enjoy it!

Mölyapina · #18 02-12-2013, 06:50 PM

309D 5-speed with granny gear:

W123 5-speed:

1983 300D automatic:

Assuming that the bellhousing are the same size, it appears it would work; however, my eyes are untrained. Thoughts?

DeliveryValve · #19 02-12-2013, 07:11 PM

I've driven a couple of 309d's before and those iron 711 transmissions are kind of loud. Plus I agree with 47dodge, you'd have to almost stop to get it from 2nd to 1st, or just into 1st gear from nuetral. Downshifting is kind of rough also. I think this trans would make your car feel like a truck.

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Mölyapina · #20 02-12-2013, 07:28 PM

Quote:

Originally Posted by DeliveryValve

I've driven a couple of 309d's before and those iron 711 transmissions are kind of loud.

Hm. How loud/would it be due to too much wear?

Plus I agree with 47dodge, you'd have to almost stop to get it from 2nd to 1st, or just into 1st gear from neutral.

...which is why I'm proposing to use it with a 2.24. I'll do the math and see what I find.

Downshifting is kind of rough also. I think this trans would make your car feel like a truck.

Again, excessive wear?

Reply within quote...

Mölyapina · #21 02-12-2013, 07:31 PM

Also, I realize that I'd have to mess with the driveshaft/a donor shaft and use 240D linkages as a base for building new ones.

DeliveryValve · #22 02-12-2013, 07:33 PM

I'm not sure if it's excessive wear. But they are truck transmissions and they act like a tough truck transmission. I'm just say'n.. if you like the feel of shifting a truck then this is the trans for you.

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Mölyapina · #23 02-12-2013, 08:01 PM

Quote:

Originally Posted by DeliveryValve

I'm not sure if it's excessive wear. But they are truck transmissions and they act like a tough truck transmission. I'm just say'n.. if you like the feel of shifting a truck then this is the trans for you.

What is the difference in shifting feel that makes you think "truck"? Long throws? Noise? Something else? Could I get a sense of this by driving a 20-year-old F150 with a standard?

DeliveryValve · #24 02-13-2013, 02:46 AM

A 20 year old ford would still shift better. These 711 trans are noisy but are built like a tank to handle heavy duty usage. The gears are not shaped like a passenger car trans gears, so shifting is clunky and requires double clutching when down shifting. I just think it wouldn't feel right in a car... Bus yes.. Car no..

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Stretch · #25 02-13-2013, 03:09 AM

Now I'm sorry to fly in the face of popular belief but I've always been pretty impressed by the car-like qualities of the TNs - compare their driving qualities with a manual gear box of the same era and I reckon they are about the same...

...I mean if you install a gear box that was designed in the 1970s you'll end up with that 1970s feel - there's no escaping it!

I actually prefer the shifting qualities of the older on the floor gear boxes than the more modern Sprinter linkages that usually spring from the dashboard tend to be really notchy and vague on the rentals that I end up having to endure.

t walgamuth · #26 02-13-2013, 05:51 AM

I would want to get measurements from the bell housing area, it may be a lot larger than the car bells. The adapter that bolts to the back of the motor may be larger in the truck/van. Also the shifter area on the van tranny looks pretty bulky to fit inside a car body.

vstech · #27 02-13-2013, 08:27 AM

IDK, those pics seem to show the truck bell is the same, and the shifter is just attached to the tail piece, it should easily be removed to use a car shifter...

t walgamuth · #28 02-13-2013, 08:47 AM

Quote:

Originally Posted by vstech

IDK, those pics seem to show the truck bell is the same, and the shifter is just attached to the tail piece, it should easily be removed to use a car shifter...

yeah, maybe. The top two bolt holes look very large and well reinforced to me. Before shelling out money to buy one I would want more pics and some measurements to be sure.

the side cover looks different to me too. Perhaps an iron case 123 tranny would look more like that truck tranny.

Mölyapina · #29 02-13-2013, 09:00 AM

Quote:

Originally Posted by DeliveryValve

A 20 year old ford would still shift better. These 711 trans are noisy but are built like a tank to handle heavy duty usage. The gears are not shaped like a passenger car trans gears, so shifting is clunky and requires double clutching when down shifting. I just think it wouldn't feel right in a car... Bus yes... Car no...

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?

Quote:

Originally Posted by Stretch

Now I'm sorry to fly in the face of popular belief but I've always been pretty impressed by the car-like qualities of the TNs - compare their driving qualities with a manual gear box of the same era and I reckon they are about the same...

...I mean if you install a gear box that was designed in the 1970s you'll end up with that 1970s feel - there's no escaping it!

I actually prefer the shifting qualities of the older on the floor gear boxes than the more modern Sprinter linkages that usually spring from the dashboard tend to be really notchy and vague on the rentals that I end up having to endure.

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.

Quote:

Originally Posted by t walgamuth

I would want to get measurements from the bell housing area, it may be a lot larger than the car bells. The adapter that bolts to the back of the motor may be larger in the truck/van. Also the shifter area on the van tranny looks pretty bulky to fit inside a car body.

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

Quote:

Originally Posted by vstech

IDK, those pics seem to show the truck bell is the same, and the shifter is just attached to the tail piece, it should easily be removed to use a car shifter...

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

Mölyapina · #30 02-13-2013, 09:16 AM

...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?