Welcome to New Venture Gear owners club...<br><br>Part of the way fifth feels is because of the shift-fork design. All other gears are shifted via top loaded forks on the mainshaft. That keeps the shift rods straight and simple (in the shift tower). The synchro assemblies are located on the mainshaft for R,1-4. The short distance the forks operate through on the synchro stop rings makes for a shorter, more precise throw (with more 'feel'). Fifth is different. The 4500 is essentially a 4 speed w/an overdrive stuck on the tail end. Hence, the synchro ends up being on the countershaft which does 2 things. One, it makes 5th shift feel different simply because of the different design mechanism. Two, it makes for a sloppy shift because the shift rod is actually a multi-part extended linkage which has a long distance to traverse (relative others). I.E., it is not a straight simple shaft, but 2 indirectly connected ones with built in &quot;looseness&quot;. Further, the fork has less effective leverage (mechanical advantage) on the synchro stop ring due to the shift rod design, so it is actually harder to engage/disengage. This probably makes no sense - hard to describe; but if you saw it, you'd understand.<br><br>The &quot;sticking 5th&quot; problem could be several things other than just the inherent inefficient design. You may have a damaged stop ring or hub/sleeve, damaged struts (though more likey to cause trouble going into, not out of 5th), strut springs, worn shift fork, or problems with the shift rod assembly in the tower. Could possibly be worn roller bearings in the countershaft gear. If you hear a lot of gear noise in 3rd, you probably have way too much clearance on the mainshaft. This will allow 5th gear (mainshaft) to 'walk' around, and can cause hard shifting. My 4500 does this constantly. Two years is about max before endplay opens too much. <br><br>Try double clutching or &quot;floating&quot; 4-5 shifts. If it helps, I'd bet on excess endplay. Too much endplay will eventually destroy the thrust bearing, input gear and rear main bearing. It will also cause your clutch disc to stick and wear around the edges; taking it, the clutch pilot and possibly input gear pilot bearing and oil seal out in the process. Been there, did that...<br><br>You may find changing oil will help some for a while, but problem will return. Mine actually worsened when changed. I'm afraid the only way to find out for sure is to pull the extension housing off the tranny (which means removing t-case on 4x4s). You can replace all the 5th components w/o removing trans from truck - except for shift rods. If you grab the mainshaft and can feel any radial play, you at least have a clearance problem, and possibly bearing problems. <br><br>One last trick - when I rebuilt my 4500, I found the 5th (lower) shift rod (which slides through the housing at rear/countershaft) had a bur on it. Some polishing w/emory paper cleaned it up and now shifts better than ever. I suppose if the rod or housing bore were worn enough, this could cause hard shifting as well - but that's pretty hard metal so don't know how likely that scenario. This tranny is pretty solid in the main case (4spd), but the 5th gear was a poor design IMHO. The high torque @ low rpms that these diesels make (along with the damaging resonances) plays havoc on the overdrive gear assembly and bearings/shims. <br><br>Sorry I don't have an easy fix to tell you about. Good luck!<br>Photo of the 5th assembly attached below...<br><br>Regards,<br>-Scott

 

Here's a better shot of the 5th countershaft gear and synchro assembly. The rod in the foreground is 5th shift rod minus the fork. On countershaft you see 5th countergear/hub unit, sleeve, clutchgear and stopring. BTW - if the sleeve is reversed (installed backward), shifting will be difficult. The sleeve will fit either way - so easy to put in wrong (same goes for other gears as well). <br><br>-Scott