1. Drivetrain
  2. How to Convert a L-Body to A-555/520

This article was written by saw wave analog on 03-23-2007.

I decided to do a write-up on this swap because it is fairly common for the L-bodies, and though there are many great references available online already detailing how this is done I discovered the hard way as I went that none of them are comprehensive.. And a few important tips that I was not given could have made my swap quite a bit less frustrating and time consuming. My experience was with an 86 omni getting an a555. as far as I know all of the L-body cars are set up the same, so this should apply to chargers and rampage/scamps as well, but there may be some slight differences. The a520/a555 are the same externally, the a523/a568 require a bit of grinding to fit them in according to those that have done the swap, but otherwise the procedure should be about the same.

Parts you will need:

Obviously this covers 555/520 swaps specifically, but 523/568 should be almost identical aside from the before mentioned grinding

All the Brackets for the Transmission
There are 3, and it is not uncommon for one or all to be missing. This caught me up and cost a few extra days the main mount bracket, which has a rubber square type bushing similar to the front motor mount.

  • The main mount bracket, which has a rubber square type bushing similar to the front motor mount
  • The cable bracket, a small squarish piece that is used to keep the cables from flopping around
  • The bobble strut bracket, this is a rectangular piece with a hole in it that the rear bobble strut connects to

Four Cable Clips
Get these from the dealer, they are $5 apiece

  • 2 identical ones that hold the shift cables into the shifter assembly
  • 2 identical (but different from the shifter assembly clips) ones to hold the cables into the tranny cable bracket

A Shifter
I used the shifter from a shadow. Mopar Nutz has informed me that the 89 shadow shifter is the one to use, because the 88 and earlier models use a straight rod, that when putting the shifter in the stock 525 location, moves the knob out farther from the driving position than the 525 was.. meaning you have to reach a bit more for 1st 3rd and especially 5th. i used an earlier model straight rod shifter in my conversion, and it is a bit farther out than would be ideal. nothing terrible, but worth mentioning.

A Pair of Shifter Cables
There appears to be 2 different styles of shifter cables and the shift arm that they attach to on the tranny, this is another place that I got hung up. I had the 2 balljoint style cables, and the ball and clip style shift arm. The generosity of a td.com member got me going again fairly quickly but it would have been nice to have known about this to begin with. make sure the cables you buy match the type of shift lever your tranny uses!

  • One style has a balljoint type connection on one of the cables, and a flat connection that you need a clip to attach to a post on the shift lever for the other
  • The other style uses balljoint type connections for both cables, one ball is slightly larger than the other

A Bobble Strut

Basically the rear mount for the tranny on a stick the l body specific a525 transmission uses a different style mount than the rest of the td cars do, instead of a bobble we got a dogbone. The problem with this is that the mounting point for the dogbone is not in the same location as the bobble strut mounts are. Luckily this problem is easily solved. There are actually 2 ways to get around it

  • That more involved method is to weld a new bracket onto your k member right next to the stock mount. Polybushings.com sells these brackets for a decent price, but I have heard that you also need to reinforce the k member where you put it because the stock steel in that spot is not designed to bear a load like that. If the k member is not reinforced your bobble strut could end up ripping a hole in it and causing all sorts of fun down the road.
  • The easier option, and the one I chose, involves running a long bolt through the bobble strut and original bracket, shimming the inside of the bracket with something, and that’s it.

Either way works fine and for simplicities sake I chose to run the bolt. I have heard that people use 11mm headbolts for this, so I went out and got one but found that there was a bit too much slop between the bolt and the inside of the strut for my tastes, so I improvised. What you want to do for the most solid connection possible is use a 7/16ths bolt and file out the inside of the bushing sleeve so it fits.. They are just *slightly* too large to fit in the sleeve without modifying it, but 15 minutes with a file gave me a rock solid connection, where the 11mm headbolt had a bit of room to bounce around in there, not to mention 11mm nuts are impossible to find. I tried a lot of different bolts and feel that this is the best solution. You will also need to shim the inside of the original bracket. I used a bunch of washers and they worked fine, I would use the largest ones you can get in there.. The bigger they are the less likely the bracket is to collapse. That would be bad

The 525 got small spline axles, the rest of the td's got large spline. There are several ways to accomplish this as well. The easiest way is to use unequal length axles, a bit more involved is the equal length setup like you have stock

  • unequal length, this is beyond simple, all you have to do is go to autozone and buy a front set of axles for a 1990 automatic omni. The later autos got large spline axles that just so happen to fit perfectly into a 520/555/523/568. this eliminates the stock intermediate shaft entirely, you just end up with one long axle and one short one. This is what I did and im not getting torque steer any worse than I did with the equal length setup, that is the only supposed benefit of equal length that I am aware of.
  • another option is to go to autozone and buy just the drivers side 1990 auto omni axle, and then go to a junkyard and find the intermediate shaft out of any large spline tranny car. Parts stores don’t sell these so you will have to track one down. Then what you do is split the u joint and attach it to the other half of the stock intermediate shaft that came out of the car, this allows you to have a large spline going into the tranny, but will drop the size down so you just reuse your stock axle after the intermediate shaft. A lot of work for not much gain if you ask me, but to each his own

Not a requirement, but you are going to have the tranny out to do this anyway.. So UPGRADE

That’s it! Now you have everything you need and we can get on to the actual swap. The only hard part of this upgrade is getting all the parts together, there isnt much to the actual job.. The only part that requires some modification is the new shifter
The Job

Drop out your 525 and throw it directly into a dumpster. Don’t think twice, just do it.

Put in your new clutch and bolt the tranny in.. Nothing special here, if it’s a 520/555 it will fit in just like stock, 523/568's may need a bit of grinding but otherwise they bolt right in just the same

Remove the stock shifter and its linkage. You will now be left with a hole in the floor and a hump that wont let you mount the new shifter easily. This can be solved by cutting the hump out and then beating the ---- out of the sheet metal with a hammer until it is level enough to mount the shifter. Once its flat cover the hole with something, I used a piece of aluminum, a bunch of silicone to seal it, and some sheetmetal screws. Now you can mount your shifter flat in the factory location, woohoo! All I did to mount mine was to get it as straight as I could, then I drilled a few holes, ran some bolts through, and tightened down the nuts on the bottom of the car. Easy. All that’s left is to pop a hole in the exhaust tunnel for the cables to pass through. This also required a bit of hammering to get the hole I drilled a bit lower so the cables could pass through easily.. The hole needs to be a bit offcenter to the left, you will figure it out once this is done you can run your cables through and connect them to the tranny. Don’t forget to put those clips in! I beat on mine with a hammer a little to make sure they were seated well, they are a very tight fit and I had one pop out on my test drive. Also, a good baseline to adjust the cables to where the connect to the shifter is all the way forward towards the firewall for both of them. In my car at least this was almost ideal.

Additional Notes

1. Mounting the shifter in the factory location puts it fairly far away from the driver, i had to move my seat forward a bit to compensate. a better solution is to mount it farther back so its easier to reach, but this involves extensive modification and you will not be able to reuse your stock console. if its a gutted car i would definately suggest mounting it farther back for the ease of shifting benefits, but for a car you want to keep clean, the stock location is not that bad. i have no problems driving and shifting with it in the stock spot, this is nothing to *really* worry about unless maybe you road race, but it is worth mentioning if you want the shifter closer to you.

now you can put your axles in, put your interior back together, and you are done! Bask in the glory of a tranny that doesn’t feel llike garbage! Yay!

2. The first axle i got was from napa and it was machined incorrectly, the input shaft was too long and it could not make a good seal with the output on the tranny causing a rather massive oil leak. autozone is known to have the best generic rebuilds out there so i went and picked one of theirs up and it fit perfectly. If you are doing this and you cant for the life of you get the axle to go in and seal, you may have been sold a junk part. it took a lot of cussing before we figured out what was going on.

3. by 87glhs465:
There is yet a third way of setting up the axles, also for equal length, which involves buying 2 auto 1990 drivers side axles. you will still need to find a large spline intermediate shaft at the boneyard, but you wont have to combine it with your old intermediate shaft because the second drivers side axle will fit right into it.

This page has been seen 779 times.

    • Last updated by on