jeepinmatt
..l.
- Joined
- Mar 24, 2005
- Location
- Stanley, NC
<pics added>
Been doing some late night fiddling here at the shop, rebuilding a Dana 300 case. I've put in the shift rails on these things many times before, and the detent ball and springs are always an exceptional pain. I planned on installing shims under the springs to stiffen it up, which meant they would be even more difficult. Long story short, instead of fighting it, I made a super simple tool, and I'll be glad to make more if anyone else wants one.
Problem:
Its not too hard to compress the spring, not too hard to hold the case, not too hard to tap on the shift rail with a hammer, but almost impossible to do all three simultaneously.
Solution:
Take an old/broken/wornout Dana 300 shift rail, and make a tool. It needs to be at least 5" long.
1. First you need to put the spring and ball in, along with any shims you might be adding. The only way I've found to accomplish this is to position the case so that the ball will rest on top of the spring when it is in the hole.
2. Next, measure or at least get an accurate eyeballing of the clearance between the ball and the shift rail bore. It will probably be somewhere between 1/8-1/4". In my experience, the front output has a deeper spring hole, and you can fit a thicker shim. The rear output spring hole may be so shallow that it is not possible to fit a shim.
3. Clamp the old/broken/wornout Dana 300 shift rail in a vise, and attack it with a grinder. The idea is to build a ramp that the ball will ride along that will push the ball down into the hole gradually. The closer to parallel with the shift rail, the better it will work. The tip can be as sharp as you want to make it, but it only needs to be slightly narrower than the gap observed in step 2.
4. After grinding to the desired angle and thickness, take a flapdisc or other smoothing tool, and put a decent surface on the ground area. This is important because you don't want the detent ball catching on any grooves or divots.
5. Once the flat surface is nice and smooth, use the same tool to deburr the edges of the area you just ground. Also, it is worth hitting the edges of any old slots or grooves to make sure they don't damage the shift rail bores in the input housing. Wipe everything clean and you are done.
6. Place shims, spring, and detent ball in shift rail housing.
7. Insert the sharp end of the tool, with the ramp facing down, into the front of the housing (the side where the two small seals seat).
8. From the back side of the housing, use a finger/socket extension/bolt to hold the ball on while you push the ramped tool inward. Continue applying pressure on the back until the ball is halfway in the hole.
9. Once the ball is halfway in, you can tap the tool on in with a small hammer (yes, they do make small hammers, but you can also use a BFH with less force). Continue until the tool is almost completely in the housing. At this point, you will find out if you put in too many shims. There will be some resistance, but you should not have to beat the shift rail in. If it seems to be stuck, take a look at the ball and make sure it is compressing at or below the bore surface. If it is not, you need to remove shims or clean out the hole better.
10. Take a punch and tap the shift rail tool on in the housing until it is recessed slightly in the bore.
11. Insert your actual shift rail into the bore, and tap until it is seated. Make sure it is oriented correctly in all three regards (lockout pills, detents, and shifter slots). If either the actual rail or the tool rail are a loose fit, make sure to keep pressure between them so that the ball doesn't push up and separate them as the end passes over.
12. Now that you have the tool, you can remove the rail to install the seals, or just push it back to where the front of the shift rail is flush with the front of the housing.
Total time to install a D300 shift rail is now about 1-2 minutes. It used to be anywhere from 5-30 minutes depending on how many times the ball and spring flew across the shop.
Been doing some late night fiddling here at the shop, rebuilding a Dana 300 case. I've put in the shift rails on these things many times before, and the detent ball and springs are always an exceptional pain. I planned on installing shims under the springs to stiffen it up, which meant they would be even more difficult. Long story short, instead of fighting it, I made a super simple tool, and I'll be glad to make more if anyone else wants one.
Problem:
Its not too hard to compress the spring, not too hard to hold the case, not too hard to tap on the shift rail with a hammer, but almost impossible to do all three simultaneously.
Solution:
Take an old/broken/wornout Dana 300 shift rail, and make a tool. It needs to be at least 5" long.
1. First you need to put the spring and ball in, along with any shims you might be adding. The only way I've found to accomplish this is to position the case so that the ball will rest on top of the spring when it is in the hole.
2. Next, measure or at least get an accurate eyeballing of the clearance between the ball and the shift rail bore. It will probably be somewhere between 1/8-1/4". In my experience, the front output has a deeper spring hole, and you can fit a thicker shim. The rear output spring hole may be so shallow that it is not possible to fit a shim.
3. Clamp the old/broken/wornout Dana 300 shift rail in a vise, and attack it with a grinder. The idea is to build a ramp that the ball will ride along that will push the ball down into the hole gradually. The closer to parallel with the shift rail, the better it will work. The tip can be as sharp as you want to make it, but it only needs to be slightly narrower than the gap observed in step 2.
4. After grinding to the desired angle and thickness, take a flapdisc or other smoothing tool, and put a decent surface on the ground area. This is important because you don't want the detent ball catching on any grooves or divots.
5. Once the flat surface is nice and smooth, use the same tool to deburr the edges of the area you just ground. Also, it is worth hitting the edges of any old slots or grooves to make sure they don't damage the shift rail bores in the input housing. Wipe everything clean and you are done.
6. Place shims, spring, and detent ball in shift rail housing.
7. Insert the sharp end of the tool, with the ramp facing down, into the front of the housing (the side where the two small seals seat).
8. From the back side of the housing, use a finger/socket extension/bolt to hold the ball on while you push the ramped tool inward. Continue applying pressure on the back until the ball is halfway in the hole.
9. Once the ball is halfway in, you can tap the tool on in with a small hammer (yes, they do make small hammers, but you can also use a BFH with less force). Continue until the tool is almost completely in the housing. At this point, you will find out if you put in too many shims. There will be some resistance, but you should not have to beat the shift rail in. If it seems to be stuck, take a look at the ball and make sure it is compressing at or below the bore surface. If it is not, you need to remove shims or clean out the hole better.
10. Take a punch and tap the shift rail tool on in the housing until it is recessed slightly in the bore.
11. Insert your actual shift rail into the bore, and tap until it is seated. Make sure it is oriented correctly in all three regards (lockout pills, detents, and shifter slots). If either the actual rail or the tool rail are a loose fit, make sure to keep pressure between them so that the ball doesn't push up and separate them as the end passes over.
12. Now that you have the tool, you can remove the rail to install the seals, or just push it back to where the front of the shift rail is flush with the front of the housing.
Total time to install a D300 shift rail is now about 1-2 minutes. It used to be anywhere from 5-30 minutes depending on how many times the ball and spring flew across the shop.
