SRK

Hi all, need some help diagnosing a clutch/transmission sound I can't isolate. Thought I'd check here before I took the whole thing apart. At low constant speeds (15-30 mph) I get a light grinding sound from the clutch/transmission and it feels like the car is missing. Push in the clutch and the sound completely goes away and the car coasts fine so I know its not something like a brake grabbing. (that's kind of what it feels like) No sound or jerkyness when accelerating or at higher speeds. I thought it might be the free play on the clutch and adjusted the pedal to have about 1.5" of play and that seemed to help a little but there's something still going on. Any ideas before I yank the transmission?

Thanks in advance!!!

Steve

LB66383

What gear are you in at 15-30 mph when you feel/hear this? Do you get the same at higher speeds in higher gears? Is it in a certain engine RPM range?

DansYellow66

Have you had any recent work done on the clutch or transmission? Has it been running fine and this just started? Does it make the sound in only 1 lower gear and none of the others. Could be internal to the transmission but hard to tell.

SRK

Typically second gear but its a good question and I will take the car out today and specifically try different gears to see if I can tell a difference.

SRK

I bought this car about 2 years ago and have driven it very little while I tinkered with things to make it inspectable. Once I got it to the point where it would pass inspection I started to drive it more (around the neighborhood which is pretty rural for Hawaii) which is when I found the issue. The PO did tell me that he had a new heavy duty clutch put in not long before I bought it.

SRK

Just ran the car to confirm what gears I get the noise/jerk in. Its worst in first gear, then second then third. I do not feel it at all in 4th. Goes away completely with the clutch in so I'm guess something internal to the transmission?

tbarb

Just a guess on my part but it sounds like the needle bearing where the main shaft rides inside the transmission input shaft.

DansYellow66

Can't imagine what would hurt the needle bearings that support the countershaft but it does sound like an issue with the countershaft since in 4th the input and output shaft are locked together. Possibly a chipped input shaft gear.

Sounds like it will probably have to come apart for inspection.

SRK

Thanks all for the insight. I guess I needed a new project anyway :-) Looks easy enough to pull out and have heard there's a couple of good transmission rebuilders on the Island. (Transmissions are the one thing I've never tackled)

Steve

DansYellow66

I just built my first Muncie with the help of parts from D&L Transmissions and it's not greatly difficult. The trick is to be able to evaluate well used parts and sort out those that are just too worn and won't function properly, from those that are just worn but still serviceable. About the only specialized tools needed were a good set of HD C-clip pliers - the type that bear on the square cut ends to spread the clip, and a 12 ton press. There wasn't much pressing that was necessary on mine but apparently it can vary from transmission to transmission.

But if you have a reputable transmission builder nearby that could be a much easier path. If you go that route you may want to let them drive the car first to see if they have any ideas on what is going on.

Good luck

tbarb

Had this happen on a Ford F700 dump truck I owned. Same grinding noise that was mentioned in the first post and the input gear needle bearings and machined race in the input gear was wore out. Bottom line is the transmission has to come apart for maintenance.

DansYellow66

OK - there are those roller bearings up top too.

babbah

Sounds like your clutch throw out bearing is going bad.

SRK

Well I retire in a few months and it sounds like a good time to learn all about transmissions! I do have any tools I would need (or would buy some if I needed more) so I'm leaning now toward tackling it myself. Thanks all for the insights!!!!

DansYellow66

It's actually a pretty good learning experience. One other tool I did splurge for was a proper front bearing retainer nut wrench. If you don't have one, I would pick up a copy of this book:
https://www.barnesandnoble.com/w/how...eId=PLGoP78860

It's good to have the factory service manual too but this book is much more helpful. The author is Paul with Paul's 5 speeds who is a great source for parts and help. I got my bearing nut wrench from Paul. Also Larry at D&L Transmissions is great for parts and help. Both are AutoGear dealers.

The only somewhat tricky part is lowering the main shaft and gear train into the case while trying to maneuver it around the countershaft so all the gears mesh and also seat it into the input shaft register. Guys that do them all the time I guess do it instinctively - for me it was kind of wiggling it around until it suddenly just slipped in place without my really knowing what I did.

L78racer