Slipping transmission
 

Last year when I bought "the monster" 1967 250s, I started a thread (vintage section) asking for info on different subject wich included slipping tranny and did not get a satisfactory answer.
Maybe some of you here may have some insight?

Here are the simptoms; it slips in all gears till it gets to 4th at 47m/h, once in 4th it dos not slip.
Once I tested it on a vacant lot, to my suprise all gears were working fine, it lasted for one pass only, then started to slip again, because the first is so short, I c'ant tell if it slips in first!
But I do know that under hevy load such as going up ramps in first it dos not slip.
Also, on hard acceleration it slips less, but still the 4th only ingage at 47m/h.

From what I have read, I'm suspecting 1 of 4 things :
1) malfonctionning silinoid switch (top of tranny)/idle/kikdown switch.
2) vacumm conduit blocked.
3) low oil pressure (worn pump, clogged valve)
4) gungk deposit in valve body (from siting to long?)

It is still winter here, so I won't be able to test you'r advice now, I will be doing those in spring.
As anyone of you hever tried a transmission cleaning agent? What was the result?

Thanks for you'r expertise

Dan

Forgot to mention that even shifting manualy dos not work.
According to the CD,
- brake shifting impossible : one or more shift sleeve stuck (sleeves 1, 2, 10, 18, 19, 20, 25, 26)
- see post above ; shift members engage only at higher engine speeds (approx. 3,000 rpm) : Main pressure control sleeve (11) stuck (pressure buildup with increasing engine speed)

Now, can I inspect/work on this sleeve box without removing the transmission?
From the diagram, I know were it is....
ps. Just examined the cd and yes I can take the valve body out without removing the transmission, but in the diagram the trans. is upside down, so I will be doing it right side up!
Any comments suggestion before I get myself in deep s"#t !?

Thanks

Dan

Good question .... anybody?

Comments anyone.......

Did you hever try a cleaning agent?

Tranny Additive
 

Go To Diesel Discussion and search on Trans-X. You should find lots of good information. I just bought an 84 300D. It ran fine for several days, now I can't get it much over 25mph. I added Trans-X, but I think it may be something other than the tranny. Got to go search. Good luck!