5-speed manual - Page 2 - PeachParts Mercedes-Benz Forum

Mölyapina · #16 05-21-2014, 06:55 PM

Quote:

Originally Posted by DieselPaul

I've never had any issues with speedo accuracy swapping to 4speed in a 123, or 5 speed in a 124. As long as the diff matched the speedo.

That's what I thought. So it's all in the speedo.

JB3 · #17 05-22-2014, 08:53 AM

i have seen several 201 and or 124 chassis 5 speeds where the bearing between input and output shafts was obliterated by unlubricated neutral towing. may not be as big an issue on this type of gearbox, but if the car was ever towed in neutral without the countershaft throwing lubricant, the most covered bearing turning at the highest speed is this bearing, which is unfortunately the one most in need of lube and not getting it. i have a horrifying pic of a towing disaster where this bearing got so hot that the end of the output shaft got snapped off in the input shaft.

im always suspicious of this bearing first, because after 30 years most of these cars have seen a tow truck, and people think that putting it in neutral and back feeding the gearbox with spinning the output shaft alone is harmless for some of these cars. works on some, but not others, but every tow truck driver will tell you its fine and argue

depends on how this bearingi s designed on your gearbox, but with the pedal out and clutch engaged like that, path of power would be input shaft ,down to countershaft, and back up to free wheeling gears on output shaft ,so noise could be from bearings for either of those two shafts or gear tooth chipped or something like that.

unless something is horribly wrong ,the reverse gear and shaft should be not touching and idle, so i doubt reverse is related.

the trick is to identify which gears its silent, and which gears some noise but not a lot are happening. for instance, if i had big noise in neutral and power going through like this, but completely silent in say 4th gear at 1 to 1 ratio where input and output are locked together, id be thinking the cause is the bearing between input and output shafts. that would be consistent with when that bearing is turning specifically, and the noise would be loudest in neutral, different in 1, 2 , and 3, quietest in 5th ,and silent in 4th

but say i still had noise in 4th ,then it couldnt be that bearing, as in 4th that bearing is not moving.
in some gears as in clutch out neutral, many bearings are turning all the time ,you can narrow it down some, but either way, you probably should break it open if its a really loud problem.

tjts1 · #18 05-22-2014, 10:15 AM

Quote:

Originally Posted by Frank Reiner

Not crazy at all; 3.46(final drive ratio) x .81(overdrive ratio) = 2.80 (engine speed to wheel speed ratio), right where it should be.

2.88x.81=2.33; too tall, even for a mighty 300TD.

Living la vida 2.64x0.80=2.11 and loving it. Different car, different engine but theres no reason a 2.88/5spd wouldn't work well in a OM617 turbo.
Gear ratio calculator

t walgamuth · #19 05-22-2014, 10:37 AM

Quote:

Originally Posted by charmalu

A 2:88 and a 4-spd is almost too tall. On the flat land it is ok, but trying to start on a steep hill and get her rolling and get the rpm`s up w/o pumping and slipping the clutch is a challenge.

Now a disclaimer: I have driven 4-spds, 5-spds with 2 spd rear ends, 10 spd road Rangers, 13 speeds etc... for a good 40 years, so kind of have an idea how to shift and use the clutch.

On the majority of hills on the HWY`s it is ok. I had to get up a very steep drive way one time and she almost would not pull it.
Could have used a lower first and a few gears in between. In this situation a 3:46 would have been good.
A 2 speed rear end in our 123`s would help.

Though most would know how to shift one.

A 2:88 on the Hwy is perfect.
A 3:07 would be good if there is mostly hilly terrain.
A 3:46 is good for low end start up, but will have the engine RPM`s running pretty high at 65mph.

I agree with Frank Reiner, a 2:88 in too tall with a 5-spd OD.
The engine will be straining to keep her up to speed, and the MPG will most likely drop.

Charlie

I had the 5 od in my 123 NA euro motor equipped car with the 307 diff. On the highway it would still accelerate without downshifting and I always thought you could to a 288 diff. To accelerate though you'd have to downshift and taking off on anything other than level ground, as Charlie noted, would be a challenge. That car would run 100 mph in fourth or fifth gear.

seo · #20 05-22-2014, 12:24 PM

Well, I have lots of differentials to choose from: 240d with 4 speed manual, 300d with 5 speed manual, 300d turbo with auto. I'll have to dig out the manuals from the 240 and 300d to see what the gear ratios are, but if this is a typical overdrive 5th transmission, I wouldn't be surprised to find that the first 4 are the same as the four speed, with 4th 1:1. But this is a mercedes. It'll probably be different.

C.Doner · #21 05-22-2014, 12:35 PM

Dont forget the transmission is geared for reverse with the 3.46 diff most likely. with the 2.88 or even the 3.07 the reverse will be too tall. I have the 346 in mine and i have not added the tach but it feels very nice. The NA 300d 4 speed w/346 will drive at 80 mph all day with no issues. With an overdrive it will be much nicer of a ride. Keep the 3.46 its designed for that transmission IMHO. Who really wants to go much over 80mph in a w123 anyway.

seo · #22 05-22-2014, 12:37 PM

I bought the car with the 5spd in it with about 180k miles on it, and the transmission clanked in neutral. It got hit four years later, maybe 240,000 miles, clanking hadn't changed at all. If I could find someone fairly nearby who has worked on these, I'd have it taken apart, since it's out of the car. Worth it to me, because it's a nice transmission, and they aren't common.
The only reason I have for thinking that it might be the layshaft is that a guy walking by on the street one day commented that I must have a Getrag 5 speed. I confirmed that, and asked how he knew. He said that he worked on Porsche's and that the mid-80's Porsche 944 had a Getrag 5 spd, and they all clanked like that. Said that for a while Porsche paid to have the tranmissions taken out and repaired, but then took the position that there was nothing wrong with the transmission, it was just noisy, and if the owner wanted to fix it, they could. I said that I'd always heard that the 944's transmission was back at the differential, and he said it was, but was a pretty standard Getrag for all that it was mounted strangely. I have no way of confirming this story.

C.Doner · #23 05-22-2014, 12:57 PM

http://www.peachparts.com/shopforum/diesel-discussion/295449-installing-my-new-getrag-5-speed-weekend-few-questions.html

Check stevo's post on the first page.
I do have a manual for these boxes. Be forewarned they are very pricey to fix if you source parts from MB. Its probably around the expense level of rebuilding an engine.

JB3 · #24 05-22-2014, 02:18 PM

Quote:

Originally Posted by seoseo

I bought the car with the 5spd in it with about 180k miles on it, and the transmission clanked in neutral. It got hit four years later, maybe 240,000 miles, clanking hadn't changed at all. If I could find someone fairly nearby who has worked on these, I'd have it taken apart, since it's out of the car. Worth it to me, because it's a nice transmission, and they aren't common.
The only reason I have for thinking that it might be the layshaft is that a guy walking by on the street one day commented that I must have a Getrag 5 speed. I confirmed that, and asked how he knew. He said that he worked on Porsche's and that the mid-80's Porsche 944 had a Getrag 5 spd, and they all clanked like that. Said that for a while Porsche paid to have the tranmissions taken out and repaired, but then took the position that there was nothing wrong with the transmission, it was just noisy, and if the owner wanted to fix it, they could. I said that I'd always heard that the 944's transmission was back at the differential, and he said it was, but was a pretty standard Getrag for all that it was mounted strangely. I have no way of confirming this story.

60k making the same noise and no change and im assuming no metal in the drain?

id call it character and keep piling them miles on

t walgamuth · #25 05-22-2014, 02:37 PM

Quote:

Originally Posted by seoseo

Well, I have lots of differentials to choose from: 240d with 4 speed manual, 300d with 5 speed manual, 300d turbo with auto. I'll have to dig out the manuals from the 240 and 300d to see what the gear ratios are, but if this is a typical overdrive 5th transmission, I wouldn't be surprised to find that the first 4 are the same as the four speed, with 4th 1:1. But this is a mercedes. It'll probably be different.

The first four gears on the 5 speed are virtually identical to the 4 speed.

Frank Reiner · #26 05-22-2014, 03:21 PM

Quote:

Originally Posted by seoseo

Well, I have lots of differentials to choose from: 240d with 4 speed manual, 300d with 5 speed manual, 300d turbo with auto. I'll have to dig out the manuals from the 240 and 300d to see what the gear ratios are, but if this is a typical overdrive 5th transmission, I wouldn't be surprised to find that the first 4 are the same as the four speed, with 4th 1:1. But this is a mercedes. It'll probably be different.

seoseo:

You can find the ratio of each of the diffs that you have stamped into the lower rear corners of the back face of the diff housing (not the cover, but right next to it).

Mölyapina · #27 05-22-2014, 05:51 PM

240D Differential Gear Ratio: 3.69:1
300D Non-Turbo Differential Gear Ratio: 3.46:1
300D Turbo Differential Gear Ratio (up through 1984): 3.07:1
300D Turbo Differential Gear Ratio (in 1985): 2.88:1

IIRC, the four-speed first gears ranged from 3.90:1 to 3.96:1. I can't remember 2nd and 3rd off the top of my head, but 4th is 1:1 in both the 4 and 5 speeds and the 717.400 5-speed (the one you have) has an 0.81:1 5th.

Mölyapina · #28 05-22-2014, 05:57 PM

Here ya go. All the 4-speed ratios:

Quote:

Originally Posted by Jooseppi Luna

716.005 and 716.006 up to April 1977: 3.90, 2.30, 1.41, 1. Rev 3.66.

716.006 starting May 1977 ("superhigh teeth"), and 716.007: 3.98, 2.29, 1.45, 1. Rev 3.74.

716.1: 3.96, 2.34, 1.44, 1. Rev 3.72.

And I *believe* these are the 717.400 gear ratios:

3.82, 2.20, 1.40, 1.00, 0.81. Reverse 3.71.

Got the 5-speed numbers from here

cho · #29 05-23-2014, 03:08 AM

Quote:

Originally Posted by Jooseppi Luna

Here ya go. All the 4-speed ratios:

And I *believe* these are the 717.400 gear ratios:

3.82, 2.20, 1.40, 1.00, 0.81. Reverse 3.71.

Got the 5-speed numbers from here

notes that comes with my 717.400 says:

1st 3.82 : 1
2nd 2.202 : 1
3rd 1.398 : 1
4th 1 : 1
5th 0.813 : 1
reverse 3.705 : 1