Grinding gear shifting into reverse

[Dan Heston]

Just finished the reinstall of our '51 230 flathead into the Coronet.  We used the original fluid drive, and tranny whi h was not rebuilt.  Now that everything is back in, we have some grinding when shifting into reverse.  The tranny wasn't opened up just reinstalled and it never did that before.  Wondering what happened that caused the problem. Hopefully someone can shed some light. Thanks. DAN

[Dan Heston]

I'm wondering if the clutch is not completely disengaging, causing the problem. I tried making the linkage a bit tighter but it didn't help the gear problem. Thoughts?

[Sniper]

linkage adjustment might be off?  I do assume you are at a complete stop before shifting, lol. 

[greg g]

With the car running t idle, and the clutch pedal all the way down, select 2nd gear momentarily then shift to reverse.  Does this lessen or stop the grinding?  If it does this is because when you select 2nd, the synchros are engaged which stops the input shaft from rotating.  This usually indicates that the clutch is not fully releasing. You can address this by lengthening the adjustment rod which will push the throw out bearing a little farther when the clutch pedal is down Al the way.  This will also stop the input shaft from training as it friction disc will be that much farther released from contact with the pressure plate.  Also assure your idle rpm are between 450 and 500.  

 

If the momentary shift into second doesn't address the grinding, you may need to go deeper into the trans itself.

[Plymouthy Adams]

IF on the install of the driveline....did you change your rear mounts to new ones.....this will often cause you to shift the position a bit and need to revisit the adjustments.

[kencombs]

Does it help to disengage the clutch, then wait for a long 3 count before shifting into reverse?  If so, you may have set the idle speed to high when reinstalling the engine.  So it takes longer for the gears to stop rotating.

[Dan Heston]

Great ideas and I'm going to check them all. I'll lower the idle a bit first.  I did use new rear mounts as well.  I tried to lengthen the clutch rod thinking the positioning of the motor was a bit off but maybe I need to do a little bit more.  I'll do the recommendations and see what happens.  Thanks everyone.