Hi,
I recently purchased a 76 300d automatic. It has some transmission issues I would like to have checked out. Before I go to a shop I want to get someone direction on what options are out there should I encounter a worst case diagnosis.
If i find myself needing a rebuilt transmission what other transmissions are compatible with the 616 engine. I have been trying to find this information but only find information about converting an automatic to a manual.
Also where are good places to source these parts?
I hope someone can shed some light or knowledge on me regarding these questions.

The transmission has a pretty massive leak and the fluid is grimy dark colored.
it shifts but hesitates for about 8-15 seconds before shifting, sometimes bucking. the transmission also whines. I believed the previous owner drove it around a lot with very low fluid in the transmission.
this alarms me and leads me to suspect it has some pretty bad damage.
Anyhow any information leading to sourcing parts and what transmissions are compatible with the w115 616 300d would be greatly appreciated. unless its best to have the tranny rebuilt if needed.

This is my first Diesel, id like to make it into a daily driver and eventually learn to work on it and maintain/fix it myself.
any resources and direction to finding repair and maintenance guides would also be appreciated as my searching has yielded very few results.
the engine runs extremely well, id like to keep it that way. I have no clue to the miles or anything else. it looks like a solid engine that someone mounted in this chassis recently as the mounts are all in good shape.
I bought it for $800 with mostly the transmission needing some attention and needing new seat foam, i don't really care if i overpaid because i totally dig it.
Thanks.

For openers, how many cylinders does the engine have?
4 cyl > OM616 > 240D
5 cyl > OM617 > 300D

The basic transmission, designated 722.1xx, aka W4B025, was used with 4 & 5 cylinder diesel engines, and 4 & 6 cylinder gas engines, between 1968 & ~ 1982. The digits that occupy the xx positions in the designation give information about specific applications.

ok, it is more than likely a 617 then.
I thought 616 and 617 marked the difference between a 115 and 123

hi mate!
if it turns out you do need a tranny, ive got a good used one out of that exact car.. keep it in mind

-jack