Dana 300 popping out of low range

[greenjeep]

To make a long story short, I broke the rear output on my Dana 300, and after staying up all night a couple buddies and I finally had the Tera heavy duty output shaft installed and the case back in the CJ about an hour and a half before I was scheduled to lead a trail. I figure that's not too bad for 3guys who had never opened a t-case before!

The problem is when I'm in 2-low and going down a hill letting my gearing slow me down, the rear shift lever walks backwards and eventually pops out of gear. I have no proplem in 4-low, 2-hi, going uphill or level. It never did this before, and we didn't mess with the shift levers. I spoke with a guy at the Terafelx Plus booth and he thought that maye we had installed one of the small gears backwards. The only piece which seemed differant was there was one gear we reused which had a small 45 degree notch on one side, which had to have been made that way, it was too perfect for it to be broken. I didn't notice which way it came out, and at 5am I didn't pay attention to which way it went in. Could that be it, and the notch designates which way to install it? If not, any suggestions?

These are the instructions we used (they could have been a little clearer if you ask me). The last page show the exploded view.

Dana 300 Heavy duty output shaft

Thanks

 

[78mitsu]

not sure with a 300, I had the same problem with a 205, I re-shimmed it and it worked, when you took it apart were there any shims in it and did you get them in the right places?

 

[greenjeep]

Here there is a fully exploded 300 if that helps.

 

[greenjeep]

not sure with a 300, I had the same problem with a 205, I re-shimmed it and it worked, when you took it apart were there any shims in it and did you get them in the right places?

We removed 3 old ones, and installed the 3 new ones like it said.

 

[DaveB]

There is a spring and ball above the shift rail that if too loose will let it walk out. My old 300 did it and on my new 300 I made sure it was tight. I would replace the spring and ball. The shift rail could also be worn a bit so i would check it out also.

 

[notajeep]

What he said. Are there heavy duty springs for a dana 300??

 

[greenjeep]

There is a spring and ball above the shift rail that if too loose will let it walk out. My old 300 did it and on my new 300 I made sure it was tight. I would replace the spring and ball. The shift rail could also be worn a bit so i would check it out also.

Can you replace those without tearing open the case again? When I shift to low, it feels solid, like it is locking in. Also, we didn't disassemble the shifters at all, you still think that's it?

 

[Caleb]

I know on 203s and 205s they have what's called detent springs. If you look at your diagram it looks like #22 (just called small parts). If those springs get worn it could cause it. My 203 on my doubler did the same thing so after trying to find new springs or stiffer springs and being unsuccessful I just shimmed it with a washer to add more tension and my 203 quit popping out of gear. You should be able to get to them without having to tear it back down. On both the 203 and 205 they are located just above the shifter rods.

 

[bobdog]

The exact same thing hapened to me after installing an Advance adapters HD output. It never did it with the original output ever. I plan to install heavier detent springs but I really don't think it will solve the problem. The thing almost wants to force itself out of rear wheel low range. I can even be holding the lever and feel it want to jump out of engagement. I have checked and double checked endplay and it is correct. I plan to pull the case again and go over everything again but I am really stumped. AA has been no help. Let me know if you find a cure.

 

[DaveB]

A stiffer spring does help so shim it with a washer if you can't find a new spring. Sometimes where the ball rides on the shift rail gets worn down and some people file the detent spot a bit more abrupt so it won't slide out as easily. When you put the lower 4:1 gears in there is more torque and the shift rail can slide out easier, the heavy duty output shaft shouldn't have made that much of a difference. There are some small nylon pieces on the end of the shift fork that sometimes break off, if they are missing it could make the problem worse.

 

[Shawn]

A stiffer spring does help so shim it with a washer if you can't find a new spring.

My 35 spline out shaft came with these washers and new springs. When I rebuilt the one in the commando I added some washers in. Putting the shaft back in is quite a pain in the ass, but it does help.

 

[Shawn]

Can you replace those without tearing open the case again?

nope, the forks are attached to the shafts.

 

[Shawn]

ps, I was told once that popping was due to the shims. I would pull out one of the shims, then two and see if it make a difference.

 

[BroncoMama]

Slightly off topic, but how did you break?

 

[greenjeep]

nope, the forks are attached to the shafts.

DAMNIT

ps, I was told once that popping was due to the shims. I would pull out one of the shims, then two and see if it make a difference.

Too many shims, I kinda figured it might be the other way around. Maybe the old ones were just "broken in" more.

Slightly off topic, but how did you break?

Top of Mirror Gulch. I bounced, and my front tires kicked out a big flat rock which my rear tires came down on, and ka blam!

 

[Shawn]

It's a starting point. The shims are easy to get to and you should be able to do it in the rig.

 

[greenjeep]

Should I take out the smallest, or biggest (there seems to be 3 different sizes)?

 

[bobdog]

Bringing this back up. I have pulled my case apart and am looking for anything that may be causing the problem. I have ordered stiffer detent ball springs from JB conversions and will be putting them in when I reassemble the case, but the springs I have now seem to be very stiff and not worn out. I have checked shaft endplay on both input and output shafts and am at the bottom end of the specs so I do not think removing front output shims is a good idea. I have dialed the shift rail and fork in on a lathe to check to see if the fork is square to the rail. I found it was .020" off where the fork contacts the slider from where it is welded to the collar that locks to the rail. I have straitened it out (in fact tweeked it .005" the other way but I really doubt this had anything to do with the problem. Did you solve the problem greenjeep, or are you just living with it as just about every so called expert I talk to on the phone says you just have to do. My case never came out of gear ever with the stock output shaft.

 

[greenjeep]

My solution has been a short bungee cord! I probably won't do anything to the internals until I get a 4 to 1, hopefully this year. Thanks for keeping me updated, let me know if you solve the problem.

 

[troutbum]

it has been mentioned several times, but incorrect end end play has been the culprit in 3 cases I have looked at.