PointedThree - sedan transmission v.s. G transmission

Welcome Guest. ( logon | register )

FAQ

Member List

Albums

Today's Posts

PointedThree : Vans, Trucks, SUVs and Other Forums : G-Class : sedan transmission v.s. G transmission

Page 2 of 2

sedan transmission v.s. G transmission

Topic Tools

Message Format

Author

Posted 4/21/2012 9:48 AM

hipine

Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
5000

Re: sedan transmission v.s. G transmission

... I took the cable from the sedan tranny and played with the length and position of where it is attached to the lever to get the right ratio of travel between the valve cover mounted arm and the lever.....

Nice work! It would be interesting to know what portion of the original "throw" of the lever you're now using with the diesel (ie something like, "total throw of the lever is 10 o'clock to 3 o'clock and my full throttle position range is now using 11 o'clock to 1 o'clock), and the place you ended up attaching the cable to the lever. Thanks for sharing!

-Dave G.

Edited by hipine 4/21/2012 9:50 AM

#203040 - in reply to #203033

Author

Posted 4/21/2012 12:53 PM

WEBIII
Extreme Veteran

Date registered: Oct 2010
Location: Inlet Beach, FL
Vehicle(s): 461.318, 463.241
Posts: 317
300

Re: sedan transmission v.s. G transmission

Does the 280GE auto-trans have the vacuum to force a 1st gear start?

#203048 - in reply to #202927

Author

Posted 4/21/2012 2:10 PM

chris505

Date registered: May 2007
Location: San Francisco
Vehicle(s): '79 280E/'80 280GE/'00 G500
300

RE: sedan transmission v.s. G transmission

hipine - 4/21/2012 6:44 AM

That's fantastic information, Chris. Thanks so much for taking the time to share it here. I know it will help a lot of people going forward.

It's interesting that they changed the transmission later in the model cycle. I wonder if they figured out a different way to sense load, other than throttle position (vacuum in the booster line won't do it, it's constant on the diesel of course). Or maybe they figured with the small rev range and torque characteristics of the diesel, it just didn't matter enough to justify the added complexity and they found a way to "set it and forget it" like Ron Popiel.

Thanks again for your recent posts. Always great to hear from you.

-Dave G.

You are very welcome Dave.

I honestly don't know how or why that transmission shifts so beautifully in all conditions, when I first saw the missing lever I was quite perplexed, but the thing performs so well I just put my hands in the air and said 'if it aint broke..." I honestly just told myself it's magic.

#203049 - in reply to #203039

Author

Posted 4/21/2012 2:14 PM

chris505

Date registered: May 2007
Location: San Francisco
Vehicle(s): '79 280E/'80 280GE/'00 G500
300

Re: sedan transmission v.s. G transmission

WEBIII - 4/21/2012 9:53 AM

Does the 280GE auto-trans have the vacuum to force a 1st gear start?

Just like the passenger car transmissions, both gas and diesel autos have an electronic first gear actuation. I think it is normal for the transmission to start in second unless the button under the throttle pedal is pressed.

#203050 - in reply to #203048

Author

Posted 4/21/2012 3:56 PM

elevatorbernie
Expert

Date registered: Aug 2006
Location: Vancouver B.C. Canada
Vehicle(s): 1989 280GE
Posts: 1347
1000

Re: sedan transmission v.s. G transmission

chris505 - 4/21/2012 11:14 AM

WEBIII - 4/21/2012 9:53 AM

Does the 280GE auto-trans have the vacuum to force a 1st gear start?

My 280GE tranny starts off in 2nd gear and only starts of in 1st if...I'm starting off up a very steep hill...or I have manually selected 1st gear in which it hold 1st until I move the shifter. The car tranny has L selector that when manually selected, starts the car in 1st but allows upshift to 2nd then holds. So I believe both G and car trans start in 2nd gear.

Edited by elevatorbernie 4/21/2012 4:00 PM

#203052 - in reply to #203050

Author

Posted 4/21/2012 7:51 PM

Razon

Date registered: Jul 2008
Location: Vancouver, BC
Vehicle(s): 1986 280ge Cabrio, 617A, 5sp manual
500

Re: sedan transmission v.s. G transmission

chris505 - 4/21/2012 11:14 AM
Just like the passenger car transmissions, both gas and diesel autos have an electronic first gear actuation. I think it is normal for the transmission to start in second unless the button under the throttle pedal is pressed.

I'm sorry, but this is all incorrect.

If wondering what the ratio of the levers should be...why worry? Just use the lever from the original engine! (see my picture)...or make one that's exactly the same.

Honestly, I don't know why all this guess on how things work when everything is explained very well in the manual.
I took a couple screenshots of the manual...sorry for the quality.

I did a few diesel conversions myself...they all shift perfect, and I never spent more than 10min performing the rod conversion and adjustment.

Edited by Razon 4/21/2012 7:52 PM

(IMG_4082small.jpg)

(2.png)

(1.jpg)

Attachments
----------------

IMG_4082small.jpg (205KB - 25 downloads)
Attachments

2.png (214KB - 21 downloads)
Attachments

1.jpg (190KB - 22 downloads)

#203056 - in reply to #203050

Author

Posted 4/21/2012 10:22 PM

hipine

Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
5000

Re: sedan transmission v.s. G transmission

Razon - 4/21/2012 5:51 PM

....If wondering what the ratio of the levers should be...why worry? ...

Not worried. Just wondering.

The reason I wonder is just from an engineering/design point of view that the stud on the short side of the lever is designed to be moved through a certain stroke distance by the throttle mechanism of the M110, relating to the throttle positions of that motor. The throttle linkage of the 617 is so different from that of the M110, it would seem to me that it would take some work to design the diesel's linkage to move the stud on the short side of the lever through the appropriate distance for the trans to be responding correctly to the diesel's fuel delivery.

But it's also possible that it really isn't too fussy as a wide range of approaches seem to result in satisfactory drivability.

Thanks for sharing the manual bits too. Not everybody has them.

-Dave G.

#203061 - in reply to #203056

Author

Posted 4/22/2012 3:34 AM

kmaser
Extreme Veteran

Date registered: Oct 2008
Location: Alberta canada / UAE
Vehicle(s): 1988 280GE SWB 617A with IP mods and HX30
Posts: 301
300

Re: sedan transmission v.s. G transmission

If wondering what the ratio of the levers should be...why worry? Just use the lever from the original engine! (see my picture)...or make one that's exactly the same.

Yes that was an option originally as I had used the lever from the M110 but I have since added an intercooler that interferes with the rod and I had to use a cable.

Thanks for the heads up on the first gear start, I read the manual when I did the swap but missed that part and the switch over valve had already been removed by the previous owner of the car so I never worried about it .

Edited by kmaser 4/22/2012 3:35 AM

#203066 - in reply to #203056

Author

Posted 4/24/2012 12:08 PM

Razon

Date registered: Jul 2008
Location: Vancouver, BC
Vehicle(s): 1986 280ge Cabrio, 617A, 5sp manual
500

RE: sedan transmission v.s. G transmission

Well Dave, I know that if the linkage on the tranny is not all the way back with the gas pedeal in the idle position, than it'll behave weird: engine will rev high before shifts, it won't downshift...even if you manually move the shifter in a lower gear...I had that once and I thought my transmission is broken. But once the "zero point" is adjusted, the travel distance and rate with respect to the gas pedal is less important though it feels very nice when everything works just right.

The vacuum influences the shifts, but it's also not as important as the position of the rod (or lenght of teh cable for those who went that way). I for one, don't want my truck to drive like a car, and I like simplicity...so I ripped out the whole vacuum system except the brakes and the engine shutoff (no tranny control valves, no vacuum modulators, no EGR valve). I manually move the shift lever into teh 1'st gear position when I want to start in 1'st and I walk it up and down through gears as it was a manual gearbox (even though it changes gears automatically just fine).

I found some parts in the manual that describe differences between auto trannies installed on gas engines vs diesel engines. I think it's important to remember what the tranny was originally installed on, and make it work the same way it regardless what the engine ahead of it is.

A few better screenshots of related sections in the manual:

(1.gif)

(2.gif)

(3.gif)

(4.gif)

(5.gif)

(6.gif)

(7.gif)

(8.gif)

(9.gif)

(10.gif)

(11.gif)

(12.gif)

Attachments
----------------

1.gif (137KB - 21 downloads)
Attachments

2.gif (157KB - 23 downloads)
Attachments

3.gif (135KB - 23 downloads)
Attachments

4.gif (137KB - 21 downloads)
Attachments

5.gif (114KB - 23 downloads)
Attachments

6.gif (85KB - 20 downloads)
Attachments

7.gif (84KB - 24 downloads)
Attachments

8.gif (184KB - 23 downloads)
Attachments

9.gif (22KB - 25 downloads)
Attachments

10.gif (107KB - 25 downloads)
Attachments

11.gif (105KB - 24 downloads)
Attachments

12.gif (34KB - 20 downloads)

#203095 - in reply to #202927

Author

Posted 4/24/2012 5:41 PM

hipine

Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
5000

RE: sedan transmission v.s. G transmission

Razon - 4/24/2012 10:08 AM

...I think it's important to remember what the tranny was originally installed on, and make it work the same way it regardless what the engine ahead of it is...

Sounds like a good aproach, and the stuff you linked looks like it'd be super helpful in approaching it that way, being able to say to oneself, "If I would have done (X) when I had my M110, I'd now do (Y) to accomplish the same goal with the diesel in place."

Thanks for sharing those side by side troubleshooting guides.

-Dave G.

#203098 - in reply to #203095

Author

Posted 4/24/2012 11:23 PM

WEBIII
Extreme Veteran

Date registered: Oct 2010
Location: Inlet Beach, FL
Vehicle(s): 461.318, 463.241
Posts: 317
300

RE: sedan transmission v.s. G transmission

Razon - 4/24/2012 11:08 AM

if the linkage on the tranny is not all the way back with the gas pedeal in the idle position, than it'll behave weird: engine will rev high before shifts, it won't downshift...even if you manually move the shifter in a lower gear...

My setup is currently exhibiting these symptoms. Thanks for the heads-up.

-Winston

#203103 - in reply to #203095

Author

Posted 4/25/2012 11:50 AM

Razon

Date registered: Jul 2008
Location: Vancouver, BC
Vehicle(s): 1986 280ge Cabrio, 617A, 5sp manual
500

RE: sedan transmission v.s. G transmission

Today, I took a couple of pics with the measurements for you guys.
To me, it looks like one arm is ~2in (50mm) and the other is just under 2 1/4in (so probably 55mm). The shorter one connects on the injection pump side, and the longer one to the transmission.