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Muncie grind

1K views 12 replies 5 participants last post by  NovaSS350 
#1 ·
The transmission from my Nova grinds when I upshift from fourth to third. It is a 70 Nova used to be a big block car. Not sure which muncie is in it. Two drain plugs if that helps. It is annoying however that when you want to pass somebody and you shift down you get a loud grind. And it only does this from fourth to third. Any ideas.
 
#4 ·
I replaced my own, but that's me...........depends on your ability, tools and how brave you are. Most of my desisions of this type depend on how broke I am.

It was a long time ago when I did this. You have to remove the main shaft, I think, and slide the gears off. Keep them in order and you won't have a problem. There are also needle bearings to contend with.
 
#7 ·
Third and fourth synchros are the easiest to replace. You must remove the input shaft bearing retainer, input shaft bearing, input shaft. The fourth gear syhchro will come out with the input shaft. You will then have to remove a snap ring on the snout of the mainshaft to remove the sycho hub which will allow you access to the third gear synchro.

If you intend on doing this yourself (it's not that difficult), I sugest you buy the video availiable from 4speeds.com on rebuilding the Muncie, it's well worth the money.

Vince
 
#9 ·
tools

It depends on if you are going to change all the syncro's or just 3/4. You can get through most muncies with out a press,,,, but every now and then you get one that is a pain and you need one L.O.L. There are tricks to get around a press though.

I would recommend that if you have it out do a total rebuild. The kits you buy have both roller bearings, 4 sincros, small part kit, gaskets, counter shaft, rear seal, bushing etc......

I have not seen the video but herd it is very detailed to help you with the rebuild....

If you pm me i can give you a step by step run down on how to do it. Again if you have some talent is is really not that hard to do with someone helping you....

Keith
 
#10 ·
A tip on the rebuild kits. There are good kits and there are not so good kits. A good rebuild kit with quality bearings will set you back about $150. Make sure the kit you buy has a new countershaft with it. The rebuild video shows you how to press the first and second gears off the mainshaft without removing the speedo gear. If you are considering the rebuild, purchase the video, it's great.

Vince
 
#11 ·
Just in case, check your clutch adjustment. If it's not completely disengaging, it can cause grinding. Usually if it's the clutch, it will grind going into all gears, but it's free & easy, plus if it's out of adjustment, it will screw up the new synchros.

When downshifting from a higher gear (4 to 3, 3 to 2, etc.), try to tap the gas just enough to raise the RPM of the engine close to what it will be in the lower gear. This eases the load on the synchros, and will help it get into gear a little easier, even with the synchros going bad. It takes a little getting used to, but it becomes second nature once you get used to it.
 
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