I'm not sure if this is the correct forum for a 1985 Ram50 question.
85Ram50 4sp manual G63B Mitsubishi motor.

It has 99977K it drives fine in the cold but once its above 70 it gets hot and starts losing power as I drive down the road. It feels like a blown cylinder or head or possibly something in the tranny. A while back it happened and I adjusted the clutch and that helped until I ran out of adjustment. When I changed the clutch which was only a few years old it wasn't very worn. But installing the new one fixed the issue for a while. Could it be the throwout bearing wearing out too fast?

I'm wondering if it is the head or the tranny. I don't see white smoke so if the tranny is just so worn out its popping out of gear or partially disengaging and lugging the motor down. When it happens I can't take off any attempt to do so stalls it out. It will idle but not drive, and sometimes will die if I rev it while sitting still. After I sit a while or pour water over the tranny housing near the starter then it drives again.

Any Ideas for what it may be?
Also could I fit the V6 out of my Dakota in this thing?

EDIT In post #29 you see I discovered the problem was the Silent shaft belt (autozone call sit balancer belt) was broken.

 

Should even with lots of modifying get a 318 in them my buddy has one it took him and his step dad 2 months of stripping and changing all the wiring then another month before it was drivable but it could possibly have something to do with your thermostat maybe radiator my van did this I replaced head gaskets it didn't help so I did a thermostat and it helped so I put a radiator in and It rarely gets hot

 

id just pull your radiator and clean it first... do the d50's have a tranny cooler for the manual trans?

 

or to eliminate the engine prob issue and narrow it down, drive it till it does this then once it does get home and do a compression test on all cylinders and see if one is abnormally low compared to the others... im not sure what the actual spec is for the compression on these tho

 

It isn't over heating its just when it gets warmed up in hot weather it reacts this way. Hauling a load also causes it.
I've run it with and without the thermostat. No effect I have the correct one in now.

I talked to the KarKing who has one for sale and he said the 3.0 6G72 motor used in the 87> years of this truck won't fit and I'll need a computer for the injection. That seems odd since I saw a couple of D50's with V8's on Youtube and one site member claims that the Dodge 318 will drop in with tranny. He wasn't sure if some or all of the mounts needed changed.
I can't do the work necessary due to my limitations. I may see about getting an OEM crate motor/Tranny. Any one know where to get that? There are a lot of websites and they aren't clear in what they post or what they say is included. I would want something complete and ready to drop in and plug in.

 

is the water pump original?... that could cause some of the symptoms of what your describing... if the blades are worn down then its not gonna cycle the coolant as good as it should and if the bearing is starting to seize it would multiply the drag the hotter it got so that could cause power loss possibly... kind a shot in the dark but if its something simple it beats buying new motor/tranny... id also pull your tranny pan and look at the metal in the pan... if its really fine like microscopic flakes that's normal wear and tear but of theres bigger chunks trannys shot

 

Thanks Grant. IDK about the water pump. I made the call and it is in the dealer being diagnosed for a flat $95 to be applied if I let them do the work. They called me almost as soon as I left it and I went back to speak to the mechanic.
He's not enamored of Mitsubishi. The problem didn't happen for him, but he just drove it a few blocks and he only let it idle to get hot. Apparently they did not relay what I told Two of the guys I spoke to. ! He thinks it may be vapor lock due to how the fuel line is run and there being no plastic spacer under the carb. ALso I put a filter in the line that is resting right on the engine. He figured the fuel was getting so hot it is turning to vapor before it gets to the jets. He also wanted to say he suspects the carb since it is not oem (Weber 2bbl) in fact all the smog stuff was removed by the guy I bought it from. He didn't understand how my tightening the cluitch cable might be helping. Me not knowing much about how it operates didn't understand why he didn't understand. He said it felt like it was slipping when he drove it. I explained how it was changed twice once by mechanic then by me and how it fixed the problem but wasn't worn out as far as I could tell when I removed it. That didn't convince him, he didn't say so but I expect he thinks I conflated two problems.
I talked him into driving until it happens and he said he'd do it and they'd call me. I expect I'll hear tomorrow since it is pretty close to quitting time right now and I have no messages.
I'll update on what they tell me. With it being only 99997 miles I hope it is something simple and maybe I will change the water pump as your suggestion does make sense.
Thanks guys

 

yeah... my w150 used to vapor lock on me ALL THE TIME!!! id have to sit on the side of the road and just wait for like 20 minutes till it cooled off enough to fill the float bowl again... jeeze I didn't even think of that!

 

Neither did I think of vapor lock duh maybe the whole thing with the cluth cable is when it works loose it might raise or lower the gas cable so it might cause the cabel to be closer to motor for more hear

 

I spoke to the dealer today. So far it was 20 degrees out of time which seems real odd since it idled fine and ran well when cold. He also says the secondaries in the carb were not pumping any gas and suspect that may be a source of the loss in power. I may have caused that when I did a carb kit a couple years ago. The losing power when hot or under load problem started long before that.
They said I would hear form them later today. I'll update when I get it back.