Reverse Grinds...???

ckruzer

ckruzer

Infidel
Joined
Jul 2, 2015
Location
asheville nc
All other gears like butter. But no matter how still or moving I am, always grinds going into reverse.

TOB issue or possible syncro issue?

Kinda baffled
 
What trans is it?

Odds are its not synchronized reverse. The non synchronized gears will show up clutch or TOB problems before other Sync'd gears
 
Aren't you running an AX15? If so, no reverse syncro. If trans input isn't dead stopped it will grind so your clutch probably isn't disengaging all the way. If you put the jeep in first or second, then right to reverse does it still grind? (that should stop the input shaft from spinning and allow reverse to mesh easily). Any vehicle without a reverse syncro will grind going into reverse if the vehicle is in motion or if there is any rpm differential input to output.

Here is an easy test you can do to see if the TOB/clutch is disengaging all the way: Jack up rear (on jackstands). Have one person in vehicle, put in gear (any gear, VEHICLE OFF!) with clutch to the floor. From under the vehicle, you should be able to turn the driveshaft by hand (I emphasize VEHICLE OFF!). There will be some resistance because your turning all the gears, tires/wheels, brakes etc, but if it is very difficult or can't spin at all your clutch is not disengaging all the way.
 
Ax15. Zero movement. Crank in neutral. Shift into rev, grind. Drive in first, stop, shift into rev: halfgrind halfclunk noise.

Seems like not enough throw, but that doesn't compute with all the other gears being like butter in ever condition?

Oh and do all older manual trans whine in rev? Past three I have had did so.
 
ckruzer said:
Ax15. Zero movement. Crank in neutral. Shift into rev, grind. Drive in first, stop, shift into rev: halfgrind halfclunk noise.

Seems like not enough throw, but that doesn't compute with all the other gears being like butter in ever condition?

Oh and do all older manual trans whine in rev? Past three I have had did so.
Click to expand...

These guys are right on about clutch not disengaging. And for the most part, reverse and some granny low first gears are straight cut vs helical for strength--which is what makes the whine.
 
I'll try the test... but again. All other gears seem fine. No grind.

And my tob setup was like 1/16 of inch. From the fingers. If not slightly less.
 
The other gears won't necessarily grind, because they have the syncros to slow the input shaft and mesh the gears, but this will wear the syncros. AX-15s do tend to make noise in reverse and a clunk is pretty normal as well for non-syncro stuff. The input shaft is likely to spin some just from the little bit of friction from the pilot bearing and/or clutch disc even when the clutch is disengaging all the way. This can cause a clunk.
 
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