Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion > Diesel Performance Tuning

LinkBack Thread Tools Display Modes
Old 10-31-2018, 12:09 AM
rwd4evr's Avatar
Master hull craftsman
Join Date: Apr 2012
Location: delaware
Posts: 735
1985 300SD shop "truck" daily driver 5 speed project

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 with a load?
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.

WARNING!!! VINTAGE MERCEDES MAY MULTIPLY UNCONTROLABLY!!! I have tons of Sl/Slc parts w108 w111 w126 and more. E-mail me with needs
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 10:59 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page