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Dana 20

73EB

Sr. Member
Joined
Feb 21, 2010
Messages
534
Loc.
Bentonville, Ar
73' 302, C4

Dana 20 J-shift grinds going into gear now. 2 hi is difficult to engauge 4 hi and low are fairly easy with some grinding. Took off the big cover and the straight teeth gears are chipped. Whats the best buget route to take? Thanks in Advance.

Jeff
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
Yep, just swap another one in. You can eliminate the grinding if you put the C4 in park before you shift the tcase or shift it with the engine off.
 
OP
OP
73EB

73EB

Sr. Member
Joined
Feb 21, 2010
Messages
534
Loc.
Bentonville, Ar
if my torque conv was not stalling would that cause my grinding in the transfer case? My t-case shifter also moves freely when changing gears. it may be just worn out. thanks.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,834
Torque converter will have nothing to do with it.

Automatics have a little more drag in them then standards do. So in nuetral all the parts want to roll around and it is easier for that mass to spin with the engine then stay put. That is the drag of all the clutch packs to spin the guts is more then the drag of the case bushings and the bands. This is all in nuetral. The very nature is the output shaft wants to spin. This is completely natural and expected. Now this drag still isn't much. Almost never enough to provide any driving force (although I have had a few cars that would have a little creep forward in nuetral).

So when the transfer case goes through nuetral the drag of the vehicle is now gone. The input gear spins up to close to engine speed. The output shaft of the transmission will do the same. Now when you try and put the transfer case into gear, the input is spinning ~500 RPM and you are crashing the gears together. That is your grinding. At this point your only safe way is to turn the engine off. Putting the transmission into part at this point is very bad. Since the output shaft of the transmission is spinning at ~500 RPM (call it about 20 MPH) it would be like sticking the transmission in park while doing 20 MPH. Since park is a tooth that locks into a gear, it is noisy and bad on parts.

Best to shift the transfer case between ranges with an automatic transmission in park. That prevents the transmission output/transfer case input from spinning up to engine speed while between ranges.

I have found that the transfer case does shift very easily as long as the gears don't have any pressure on them and they line up. That may not be an issue. But the shifter could also be worn out and not actually working the transfer case and feel light, that would be a shifter issue.

As for the chipped gears. Are they really chipped? the leading edges have a little bevel to them to help them engage that I remember. So check and see if the chipped teeth are machined chips or if they are really raw fractures. There may be nothing wrong.

It may be simple as changing your shifting style to fix all your problems.
 
OP
OP
73EB

73EB

Sr. Member
Joined
Feb 21, 2010
Messages
534
Loc.
Bentonville, Ar
Torque converter will have nothing to do with it.

Automatics have a little more drag in them then standards do. So in nuetral all the parts want to roll around and it is easier for that mass to spin with the engine then stay put. That is the drag of all the clutch packs to spin the guts is more then the drag of the case bushings and the bands. This is all in nuetral. The very nature is the output shaft wants to spin. This is completely natural and expected. Now this drag still isn't much. Almost never enough to provide any driving force (although I have had a few cars that would have a little creep forward in nuetral).

So when the transfer case goes through nuetral the drag of the vehicle is now gone. The input gear spins up to close to engine speed. The output shaft of the transmission will do the same. Now when you try and put the transfer case into gear, the input is spinning ~500 RPM and you are crashing the gears together. That is your grinding. At this point your only safe way is to turn the engine off. Putting the transmission into part at this point is very bad. Since the output shaft of the transmission is spinning at ~500 RPM (call it about 20 MPH) it would be like sticking the transmission in park while doing 20 MPH. Since park is a tooth that locks into a gear, it is noisy and bad on parts.

Best to shift the transfer case between ranges with an automatic transmission in park. That prevents the transmission output/transfer case input from spinning up to engine speed while between ranges.

I have found that the transfer case does shift very easily as long as the gears don't have any pressure on them and they line up. That may not be an issue. But the shifter could also be worn out and not actually working the transfer case and feel light, that would be a shifter issue.

As for the chipped gears. Are they really chipped? the leading edges have a little bevel to them to help them engage that I remember. So check and see if the chipped teeth are machined chips or if they are really raw fractures. There may be nothing wrong.

It may be simple as changing your shifting style to fix all your problems.

Thanks for all the info and taking the time to type it.

All three gears that are located toward the back of the vehicle are chipped in a way that it appears it was not being engauged all the way. Therefore once power was applied to those gears there was not enough surface contact to uphold the power chipping off corners.

Its definely not the factory beveled edge there are uneven chunks or chips taken out. All gears have most of their surface area left.

My front output shaft (to front axle) has some visable in and out play. I would say about an 1/16 inch. It has and up and down play but its not visable, you can only feel it. My rear output shaft is tight in all directions.

I forgot to look and see if the shift forks were loose in the shift rails while i had the cover off. I think it is a possibilty after thinking about it or like you said a worn shifter. I would love to twin stick it but thats out of my budget. Thanks again to all for your input.
Jeff
 
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