Manual transmission shudder in third

sarah8394

I have a '98 S10 2WD 4 cylinder pickup. It has a five speed manual transmission, I believe it's the NV1500. There's a shudder in the top of the second gear power band, and all the way through third gear. Also, it clanks in the rear of the truck when I take off from a stop, and occasionally when up-shifting from one gear to the next. I have replaced the fluid, I used Royal Purple Synchromax. I topped off the fluid in the rear diff, and replaced the driveshaft center support bearing, which was rather worn out. The clutch needs bled, but I don't think that's the culprit. Is this possibly a worn out clutch issue, or more of a synchronizer problem?  I will also be checking the brakes at my earliest convenience. Any advice/suggestion is welcome. 

sarah8394

What would adding, say, .5 ounces of friction modifier to the trans and diff do? Would that cause more harm than good? I didn't really have this issue until I changed the trans fluid, but I researched before and made sure to use the correct fluid. I am thinking that, since I got the truck used,something may have been done to correct this issue previously that I am unaware of. Please help if you have had this same problem and know of a solution. 

sarah8394

Also, the plan is, today, to put her on stands and start checking EVERYTHING. Brakes, rear diff and yoke, clutch, ignition components, etc. I will repost if I am able to locate the culprit. Really hoping it's not a trans rebuild.....

Steve Elias

is the sound a metal-on-metal scape, or just one clunk? especially if any scraping sound, i would suspect an internal wiggly clutch issue could be involved - not visible unless clutch is disassembled. it sounds similar to symptoms i heard after pilot bearing on 05 GTO clutch dissolved at around 80k miles, and major damage had started to accrue (engine rear seal and transmission input shaft both required replacement along with clutch.)