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Old 10-31-2018, 10:28 AM
strelnik strelnik is offline
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Join Date: Aug 2007
Location: SE Mich
Posts: 3,268
Originally Posted by rwd4evr View Post
I am tired of 12-18 mpg in my v8 mountaineer. It rides ****ty and handles bad. I need a wagon or pickup and wont deal with a w124 gas car though. So I picked up a prettty decent 300sd dirt cheap and have some plans. I have most of the info I need but I need some opinions and real world experience if possible.
The plan is to swap in an AX15 5 speed from a dodge Dakota. I have the adapter kit intended to put a om617 in a jeep. The gear ratios are almost identical in the transmissions plus a .79 OD in the ax15. I will be doing some towing with the car as much as a car in flat tow or a dolly, probably not a car on a trailer. It weighs almost as much as my mountaineer and has better brakes and suspension so I'm not concerned with that. It's not hard to build a class 3 hitch into the rear structure. I will also probably down the road a bit be chopping the back roof off and welding the rear doors shut to make it a pickup. A early s10 cap will fit pretty well.
So my questions are about power and gearing. Has anyone done any towing (or driving for that matter)with a turbo 617 with the 2.88 factory rear axle ratio changed? I have 3.07, 3.23, and 3.69 differentials available. 3.69 is dumb since it would actually end up as a 2.91 final with od. All the gear change threads I've found are NA cars and have power issues. I had s 85 300TDt which felt like it had plenty of power to pull more gear on the highway. So I could go with a 3.07 to get a little more off the line and considerable reduction in highway rpm or 3.23 which has a lsd(really makes me lean this way) and would really help with off the line towing my drift car or parts cars and would still reduce higway rpm with a 2.55 final drive in 5th. The only problem I'm worried about is if it can't pull od on the higway with a load in 5th I'll be increasing cruise rpm havling to run 4 th. So at that point should I just leave the stock gearing and get awesome everyday mileage and probably have to run 4th on the highway?
On top of that how about practical power increase in a om 617? I remember years ago hearing about larger elements being installed in a NA300d om617(which I have). Any input would be great. I miss driving a Mercedes everyday so it's time.

I purchased a 1982 300SD from someone on this forum. It had a lightweight trailer hitch that would only pull a very small 1-7/8" ball + trailer.
I removed that hitch when I had the car's rear quarter and rear bumper painted. I can tell you that with the vehicle's current stock AT the car is responsive, even when loaded with 4 x 200lb passengers. I don't know if that helps, but though you should know.

I'd love to put an MT into my 617.951 in a 126 body. Don't know if anyone has done that.
Invest in America: Buy a Congressman!

1950 170SD
1951 Citroen 11BN
1953 Citroen 11BNF limo
1953 220a project
1959 180D
1960 190D
1960 Borgward Isabella TS 2dr
1983 240D daily driver
1983 380SL
1990 350SDL daily driver alt
3 x Citroen DS21M, down from 5
3 x Citroen 2CV, down from 6

Last edited by strelnik; 11-02-2018 at 03:43 PM.
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