Can anyone tell me what parts could be worn to make the trans want to jump out of 8th gear.
The 9513 was a gear box that did not like to be preselected on the gear splits in the back section. The Splitter shift fork is more than likely shot along with the splitter sliding clutch. With that said is shift lever moving out of gear or does it jump out and gear shift lever stay engaged?
The lever moves out. When I drove it home Saturday I would bungee it back while on the straight sections and it stayed in fine. Apparently someone has changed the shifter knob because it doesn't have the selector for the od spit. I want to get everything working right on it. It's in a '74 Dodge 900 with a Cummins 230 it used to be a tandem tractor and now it's a single Rockwell with a 16' flat dump.
4th/8th gear and 4th/8th gear sliding clutch
That's right,it jumped out of 4th one time Saturday. I drove it 250 miles on two lanes through the north GA mountains Saturday.
My vote is worn out clutch on the mainshaft for 4th/8th as well.
Do you have to pull the trans to replace it or can you pull the rear section and do it?
Cool Dodge. On to the trans, yes you will be pulling it, and you will be looking at a few special tools (countershaft timing tools) to reassemble it plus a good manual. Could be easier to find a good used replacement or possibly look into a reman unit (not cheap). The timing tools save time and pinched fingers.
Remove shift tower, four bolts, and check the detent springs under it. Sometimes they get weak and or break. The one in question is on the right. Mack had a TSB for Cruiseliners with a Fuller jumping out of gear. Replace the orange spring with a purple one. It is stronger and will keep the cab over linkage from bumping it out of gear. While everything everyone has said is correct we sometimes did off base things when we had to go and or were broke. On a 95 series the front sliding clutch can be replaced without disassembling the transmission. The trans has to be pulled and the top removed. Then the input shaft has to be removed. The front sliding clutch will come out through the drive gear and put the new one in the same way. This is not easy by itself. Understand that is just a patch but many ran a long time after that. Past that a reman is in order. Very few are up to a Fuller rebuild. We like pictures! Good Luck.
Wouldn't a faulty detent/detent spring also cause the gear on the position opposite to be thrown out as well?
Have at it boys.
Yes but a heavier spring can sometimes buy some time for a worn sliding clutch and or gear.
are these parts hard to come by? I've seen some sliding clutches on e-bay,I don't know what the #'ers are that I need. I have a service manual somewhere that I have to find since I moved.
Those parts are available. Truthfully you need to have someone experienced in Eaton transmissions take a look at it. Other wise your throwing darts blindfolded. Those transmissions aren't worth much so you want to watch what you spend.
Another thing to consider is that a transmission is made up of a group of parts working together. If one part is worn, most likely whatever runs next to it is also worn. You might consider swapping out for a rebuilt and not worry about another breakdown that could be more costly.