722.1 W4A018 - is it upgradable?
722.1 W4A018 - is it upgradable?
12-04-2009, 01:54 AM
#1
I am in the process of rebuilding a 300GD (Gelandewagen) with the above transmission. The motor is the venerable OM617 with an aftermarket turbo. From the information posted by Forcedinduction this gearbox is rated at 130lbft, and I expect the motor will do 180.
As I am hoping to tow a 1T trailer, I am wondering how the box will handle this, or if there is a way of upgrading it. Any ideas please?
Thanks
Hi All
I am in the process of rebuilding a 300GD (Gelandewagen) with the above transmission. The motor is the venerable OM617 with an aftermarket turbo. From the information posted by Forcedinduction this gearbox is rated at 130lbft, and I expect the motor will do 180.
As I am hoping to tow a 1T trailer, I am wondering how the box will handle this, or if there is a way of upgrading it. Any ideas please?
Thanks
12-05-2009, 01:53 PM
#4
(12-04-2009, 09:35 AM)ForcedInduction You should be able to swap in a 722.3 without too much work.
More or less work than a manual conversion?
John Robbins
'05 E320 CDI - 118k - Faaaaaast!!
'87 300TD - 317k - Cracked head... but an OM606 is on the way!
'79 300SD - 295k - Bad engine = project car!
(12-04-2009, 09:35 AM)ForcedInduction You should be able to swap in a 722.3 without too much work.
More or less work than a manual conversion?
John Robbins
'05 E320 CDI - 118k - Faaaaaast!!
'87 300TD - 317k - Cracked head... but an OM606 is on the way!
'79 300SD - 295k - Bad engine = project car!
12-05-2009, 04:37 PM
#5
This post was last modified: 12-05-2009, 04:38 PM by ForcedInduction.
ForcedInduction
12-05-2009, 04:37 PM
#5
A manual conversion is more work, but the steps, costs and results are well known.
12-08-2009, 04:33 PM
#7
I think I might look into adapting our motors to GM automatics. Common as dirt and the wimpiest RWD auto they offer would probably take anything a mildly modified OM617a, and after all, they're proven to be capable of massive torque capacity when built, being the drag race transmissions of choice practically the world over - even pushrod hatin' ricers use them. They all use slip yokes, too so a one piece U jointed shaft would be easy.
CID Vicious
12-08-2009, 04:33 PM #7Much cheaper, they're not all that different. I'm kind of surprised that MB has a use for such a wimpy trans in that truck anyway, doesn't make too much sense to me.
I think I might look into adapting our motors to GM automatics. Common as dirt and the wimpiest RWD auto they offer would probably take anything a mildly modified OM617a, and after all, they're proven to be capable of massive torque capacity when built, being the drag race transmissions of choice practically the world over - even pushrod hatin' ricers use them. They all use slip yokes, too so a one piece U jointed shaft would be easy.
12-09-2009, 01:21 PM
#9
(12-08-2009, 10:41 PM)Dusty-G CID, the OM617 only puts out 178Nm or thereabouts. The diff ratio though is 4.88 or higher to compensate...
Think about it: you're going rock climbing, and say you're 225 lbs like I am. Are going to buy the rope that's rated for 230 lbs, or the rope that's rated for 400? The 722.3 has:
722.3 (W4A040)- 290lb/ft
So you'd have to do some serious power seeking before you'd be at capacity, much less over it. The weaker transmission will probably be ok under normal driving conditions but once you're asking for it to really work, like say having to pass someone going up a grade, or in an emergency avoidance maneuver - things that stress the transmission - you're going to hurt it, and you might only get to hurt it once. And forget towing anything, even a fat ass would be too much stress for that stock trans
. The GM transmissions would be for people going after stupid power, or those who simply want the beefiest automatics available this side of Allison. Our four speed autos are just that, four speeds, NOT overdrive automatics like a 700R4. I don't know what the prices are on a MB six speed auto but I'd bet that the GM version would be half as costly and just as good of an upgrade for our cars, and probably already has been figured out as far as retrofitting to older vehicles. Ask the people that have tried to get transmission shops to upgrade a MB trans and more often than not they'll look at you like you have two heads, that's about how many people know how to properly mod one in this country.
Plus, if the 10mm element mod goes half as well as one might hope, all of a sudden the Finns won't be the only folk with 300+hp OM617s. Once that kind of power is reached, if you want an auto that will handle it, the only MB choice is really the very expensive, very complicated six speed. Meanwhile, if you were, say, only interested in drag racing, a common-as-dirt-and-nearly-as-cheap TH350 trans can be had for nothing and when it gets eaten can be built to handle whatever one of our engines could put out for not much. TH400s were designed to live behind nasty big block V8s and probably would require no mods at all. Want an OD fourth gear? 200-4R or 700R4. Meanwhile the MB auto transmission from this era rarely had to deal with any kind of power over 200 horses, and even the 6.9 wasn't over 300. (Torque figures were higher, I know.)
These transmissions are already known quantities and are available in every junk yard in America that isn't dedicated to a single specific make, with no Benz Tax attached. Other GM auto users include pre-Ford Jaguar (the only part on those cars that could be considered reliable), Rolls Royce/Bently (they wanted an auto that would live behind a turbocharged big block V8), every UPS truck on the road not running the new hydraulic drive, and more, I'm sure.
CID Vicious
12-09-2009, 01:21 PM #9(12-08-2009, 10:41 PM)Dusty-G CID, the OM617 only puts out 178Nm or thereabouts. The diff ratio though is 4.88 or higher to compensate...
Think about it: you're going rock climbing, and say you're 225 lbs like I am. Are going to buy the rope that's rated for 230 lbs, or the rope that's rated for 400? The 722.3 has:
722.3 (W4A040)- 290lb/ft
So you'd have to do some serious power seeking before you'd be at capacity, much less over it. The weaker transmission will probably be ok under normal driving conditions but once you're asking for it to really work, like say having to pass someone going up a grade, or in an emergency avoidance maneuver - things that stress the transmission - you're going to hurt it, and you might only get to hurt it once. And forget towing anything, even a fat ass would be too much stress for that stock trans
. The GM transmissions would be for people going after stupid power, or those who simply want the beefiest automatics available this side of Allison. Our four speed autos are just that, four speeds, NOT overdrive automatics like a 700R4. I don't know what the prices are on a MB six speed auto but I'd bet that the GM version would be half as costly and just as good of an upgrade for our cars, and probably already has been figured out as far as retrofitting to older vehicles. Ask the people that have tried to get transmission shops to upgrade a MB trans and more often than not they'll look at you like you have two heads, that's about how many people know how to properly mod one in this country.
Plus, if the 10mm element mod goes half as well as one might hope, all of a sudden the Finns won't be the only folk with 300+hp OM617s. Once that kind of power is reached, if you want an auto that will handle it, the only MB choice is really the very expensive, very complicated six speed. Meanwhile, if you were, say, only interested in drag racing, a common-as-dirt-and-nearly-as-cheap TH350 trans can be had for nothing and when it gets eaten can be built to handle whatever one of our engines could put out for not much. TH400s were designed to live behind nasty big block V8s and probably would require no mods at all. Want an OD fourth gear? 200-4R or 700R4. Meanwhile the MB auto transmission from this era rarely had to deal with any kind of power over 200 horses, and even the 6.9 wasn't over 300. (Torque figures were higher, I know.)
These transmissions are already known quantities and are available in every junk yard in America that isn't dedicated to a single specific make, with no Benz Tax attached. Other GM auto users include pre-Ford Jaguar (the only part on those cars that could be considered reliable), Rolls Royce/Bently (they wanted an auto that would live behind a turbocharged big block V8), every UPS truck on the road not running the new hydraulic drive, and more, I'm sure.
12-09-2009, 09:06 PM
#10
One reason I am asking this question is that before I rebuild the gearbox and motor I want to have some idea of its performance. There are other options in terms of engine/gearbox which may cost the same to install as the above rebuilds. My preference is to rebuild, if only because there is less risk and also because this is not a well-trodden path with these cars. Given what can be achieved in lifting the OM617 performance, I am hoping that something equivalent can be done with the gearbox. Cheers.
12-14-2009, 01:56 AM
#11
Sticking to the MB tranny will probably be best for resale value too.
I just installed the 722.4 (had to for California certification reasons). It wasn't that hard and I was converting from the manual gearbox. I'm going to see how it holds up but I have a 5-speed manual waiting for if/when it burns out.
This post was last modified: 12-14-2009, 02:08 AM by Syncro_G.
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'84 G-Wagen turbodiesel
'75 240D 4-Speed
Hey Dusty-G - I think the 722.3 will be the easiest. There's really not that much to hooking up these transmissions. If the transmissions are different lengths, you might need to shim or shorten your short-shaft.
Sticking to the MB tranny will probably be best for resale value too.
I just installed the 722.4 (had to for California certification reasons). It wasn't that hard and I was converting from the manual gearbox. I'm going to see how it holds up but I have a 5-speed manual waiting for if/when it burns out.
-------------
'84 G-Wagen turbodiesel
'75 240D 4-Speed
12-15-2009, 09:56 PM
#13
(12-14-2009, 09:43 PM)Dusty-G Briefly, could you give a list of steps/mods that you took in your installation of the 722.3 behind the OM617?
What I did wasn't exactly the same as what you'd do. I put in an engine and transmission as a unit and was changing from a manual gearbox so I had to do things differently.
I'm not that well versed in what cars use which transmissions but generally, 722.3 is found on the 123 diesel cars - 300D, 300TD, etc.
You have to use one from a 617 (turbo or N/A) diesel or the bell housing won't match.
for removal and installation instructions, follow the shop manual.
G-specific issues:
output flange from G-transmission needs to be swapped over to sedan transmission. search P3 (www.pointedthree.com) about that - you might need a spacer behind the flange (I found a perfect sized washer in the grainger catalog but ultimately didn't need it)
measure length of both transmissions (with G output flange on them)
If they are different, you may need to modify your driveshaft. search P3 for that.
wire harness connectors at transmission might be different. There are several ways to fix that - either swap out harnesses or open up the connectors at the transmission end and swap them out (likely requires some soldering)
You might have a transfer case triangle brace that connects to transmission. If the two transmissions are similar in length, you might not need to modify the brace. swap the bracket over that the brace connects to.
bowden cable should hook right up.
shift linkage should hook right up. You may want to transfer the lever arm on the side of the 722.1 to the 722.3 if the arm lengths are different.
I've seen pictures of that on P3 somewhere.
transfer the speedo plug from the old to the new transmission (speedo cable is on transfer case)
I might have missed something but that's pretty much it.
-------------
'84 G-Wagen turbodiesel
'75 240D 4-Speed
(12-14-2009, 09:43 PM)Dusty-G Briefly, could you give a list of steps/mods that you took in your installation of the 722.3 behind the OM617?
What I did wasn't exactly the same as what you'd do. I put in an engine and transmission as a unit and was changing from a manual gearbox so I had to do things differently.
I'm not that well versed in what cars use which transmissions but generally, 722.3 is found on the 123 diesel cars - 300D, 300TD, etc.
You have to use one from a 617 (turbo or N/A) diesel or the bell housing won't match.
for removal and installation instructions, follow the shop manual.
G-specific issues:
output flange from G-transmission needs to be swapped over to sedan transmission. search P3 (www.pointedthree.com) about that - you might need a spacer behind the flange (I found a perfect sized washer in the grainger catalog but ultimately didn't need it)
measure length of both transmissions (with G output flange on them)
If they are different, you may need to modify your driveshaft. search P3 for that.
wire harness connectors at transmission might be different. There are several ways to fix that - either swap out harnesses or open up the connectors at the transmission end and swap them out (likely requires some soldering)
You might have a transfer case triangle brace that connects to transmission. If the two transmissions are similar in length, you might not need to modify the brace. swap the bracket over that the brace connects to.
bowden cable should hook right up.
shift linkage should hook right up. You may want to transfer the lever arm on the side of the 722.1 to the 722.3 if the arm lengths are different.
I've seen pictures of that on P3 somewhere.
transfer the speedo plug from the old to the new transmission (speedo cable is on transfer case)
I might have missed something but that's pretty much it.
-------------
'84 G-Wagen turbodiesel
'75 240D 4-Speed
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