FYI: 300SD transplanted to 350SD body

[whunter]

Here is a list of issues I have found while transplanting the 300SD engine/transmission into a 350SD body.

We used the 300SD transmission cross-member, and ripped out rubber body plugs covering the needed mount holes.

Driver side, the engine shock mount bracket is on the front of the cross-member, and identical to the passenger bracket. I made a template of the correct mounting location, and used an angle grinder to remove the welds from the correct bracket on the 300SD.
The welds are at top and bottom.

Removed 350SD engine oil cooler from body, not compatible, and takes space needed to mount the OM617.

Removed the 350SD power steering oil cooler, due to hard contact with the A/C and engine oil cooler lines.

Removed the three piece drive shaft, the flange is too large to fit the 300SD transmission.

Removed the incompatible 350SD rear sub-frame assembly, the flange is too large to fit the 300SD drive shaft, and differential location is shifted roughly six inches to the driver side.

Installed the 300SD rear sub-frame assembly, ripped out rubber body plugs covering the needed mount holes. The mounting nuts are on a removable tabbed strip, which came out with a small screwdriver and moved to the alternate mount location.

The 350SD drive shaft carrier bearing body mounts do NOT match up to the 300SD drive shaft.
After investigation, I have decided to use bolts to install this bracket into the new body, (reasoning) it is my personal daily driver, minimal body alteration corrosion points, Michigan corrosion will probably eat the body before the bracket fails, and if it should fail; I can weld it in..
Transplanting the 300SD drive shaft carrier bearing body mount bracket:
* It was necessary to make a location template for the drive shaft carrier bearing body mount bracket.
* Drill out the spot welds, and remove the bracket.
* Clean it with wire wheels and grinders.
* Weld unusable position spot weld holes.
* Drill new usable aligned holes.
* Clean it with wire wheels and grinders, and solvent.
*** For best results Ambient temperature should be 70F or higher.
**** Danger::: Always use a respirator when using these chemicals and paints****
* Sprayed it with a rust stopper, allow to fully dry.
* Sprayed with primer, allow to fully dry.
* Sprayed it with multiple coats of good quality exterior automotive paint.
* When fully cured/dry, it was installed to the body using the template.
* Used an angle air drill in the tunnel to cut the holes.
* Applied rust inhibitor to raw edges, and painted.
* Installed nine 17mm head bolts with large washers from inside the passenger compartment, nine 17mm head nuts with large washers in the drive shaft tunnel, all with a generous serving of LoctiteŽ.
* Tightened all fasteners to 45 foot pound.
* Sprayed all of the fasteners with a rust stopper, allow to fully dry.
* Sprayed with primer, allow to fully dry.
* Sprayed it with multiple coats of good quality exterior automotive paint.
* The under body was sealed with undercoat.
NOTE: The 350SD drive shaft carrier bearing body mount brackets will be cut off, and the body areas treated and sealed against corrosion.

[mplafleur]

Sounds like a LOT of work!

[amosfella]

What year is the 350sd?? Is it the 140 body??

[whunter]

Originally Posted by amosfella

What year is the 350sd?? Is it the 140 body??

Model: 350SD
Chassis: W126.134
Years: 1991
Engine: OM603.970 I6