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1986 G300 Diesel transmission problem

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Old Nov 5, 2015 | 10:20 PM
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1986 G 300 diesel
1986 G300 Diesel transmission problem

Hi, Recently bought a 1986 G300 diesel (W460) with an automatic transmission. The problem is that the trans isn't shifting properly. The engine will be at or near redline for a few seconds then the trans upshifts abruptly kind of like the car thinks you are flooring it and is trying to hold the gear as long as possible to accelerate. My suspicion is that there is a vacuum leak somewhere but without even the owners manual for the car I don't really know where to start. So I'm asking for help with both finding the manual and other diagrams and possibly a fix.

Thanks

TL;DR bought 1986 G300 diesel and having shift problems with automatic transmission. Possible vacuum leak?
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Old Nov 6, 2015 | 11:59 AM
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1986 G 300 diesel
More info. Did some vacuum tests and turns out this part appears to be leaking. The problem is I don't know what the part is called anyone got any input

For reference it's hooked up to the transmission (720.1 auto I think) and its got a vacuum hose attached. I figure its a valve or modulator that controls the shift points.
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