My 76 L-48 with 4spd is making 2 nasty sounds- first, when shifting, I hear a clunk (only when driving- not at idle). 2nd, I hear a growling sound (from clutch or trans- not sure), that goes away when I push the clutch in. When I let off the clutch, the sound comes back. Any idea?

 

ttt

 

Make a quick check to make sure you didn't lose your differential pinion snubber bolt and bushing. GrandSport and I both lost ours and the draivetrain made some nasty noises. He has replaced his with no damage to the car, I have not done it yet but will in the next few weeks and hope to hav no damage.

 

I will check that bolt- that could be the cause of the clunking sound, but the grinding/growling sound comes from the front of the car- and it happens when the car is stationary- every single time I let off of the clutch. Any other thoughts?

 

With clutch out, input shaft turning. Sounds like front bearing or cluster shaft bearings. Clunk could be from slop allowed by bad bearings. Suggest you fix asap to avoid further damage. If noise goes away or diminishes in 4th gear that would indicate cluster shaft bearing since the load is removed from the cluster shaft in high gear, if it worsens, it is the front bearing...IMHO.
Jim

 

I assume you have a proper level of trans. oil........

 

Jim, thats the first thing I checked (trans fluid).
Since I believe replacing the bearings would be beyond my mechanical abilities, I guess I will take it to a transmission shop. Any ball-park figure of the cost of replacing the front bearing or cluster pack bearings?

Thanks for the help.

 

I wish I could tell you the anticipated cost but it's been many years since I rebuilt them and was familiar with pricing. Cluster gear bearings are needle bearings and don't usually go out unless very high mileage. High gear shaft bearings not uncommon to fail since that's where most of the forces are exerted. You could save some money by pulling trans. yourself and I would be there when they tore it down and be shown the parts indicated as bad. AAMCO is one of the worst places to take transmissions IMO. I would source out a recommendation for a reputable shop in your area from other forum members or friends. Word of mouth is usually a good indicator of a good shop. You may be due for sycronizer rings while you have it dis-assembled. These act like brakes to stop the gear from turning while you shift to allow syncronizer sleeve to slide into the gear. They wear out over time and are usually the cause of hard shifting and/or grinding while shifting. If I had to guess..I would say $300-$500 if you take transmission out and carry it to them. Depending on their condition, you may need a new clutch, pressure plate, release bearing & pilot bushing while you are at it. Always resurface flywheel and keep all traces of grease/oil of the clutch disc and associated surfaces to avoid clutch chatter on re-assembly. Wipe everything down with laquer thinner get things clean. Let me know if you need more info.
JIM :cheers:

 

bhblue80,
Dont' let the mechanical abilities thing scares you, unless you have some physical limitation! That how I was, but after rebuilt the 3rd Muncie, I could rebuild the tran within 2 hours.

The rebuild kit is around $170 (all bearings, synchro rings, seals, gasket, bushing....).

For the front bearing only ($30), you don't need to disassemble the tran. It's 30 minutes job is the most, not including dropping the tran. Since you need to drop the tran, why not rebuild the whole thing! How I would do it.

 

I had the same symptoms just last week. The clutch-noise was the throw-out bearing, and yes the tranny was in a dowmward spiral otherwise. I don't have a shop to use right now 'cuz we're building a new garage :yesnod: so, I brought it to a mechanic I know who also races. He's pulling it, rebuilding the tranny, plat, clutch, re-surfacing the flywheel, everything re-installed for a G. It ain't cheap, but it'll be done right :thumbs: Find a good trustworthy shop if you can't do it yourself. Ask a friend who has a nice car who he knows...
Keep us posted!