3.05FD Hybrid trans facts

[cordes]

I thought I would put together a quick post with some information to help out folks doing a hybrid trans and for anyone thinking of going with a gear out of a 525 regardless of the FD.

1. You will need to have the ring gear machined to accept the larger 520 or OBX diff. when using the 525 ring gear. You will need new holes drilled in the ring gear 8 new ones and 4 will be bored out larger.

2. 4 of the 525 ring gear holes almost line up so the machinist will radius the holes in the diff ever so slightly so that those can be used.

3. With the OBX I have, my machinist will probably need to open it up some so that it is not a press fit to get the 525 ring gear onto the diff.

4. If you look at DJ's build thread he shows how he swapped everything on the main shaft. I followed his directions and that worked out almost perfectly. I was able to remove everything from the 525 set with only two screwdrivers. However, the 555 set required the bearing splitter he used and also a very large 3 jaw puller to get 2nd gear off the shaft.

http://www.turbo-mopar.com/forums/sh...6&postcount=27

5. The 525 main shaft uses a different method of stopping the thrust washer from spinning than the 555. The 525 pieces fit into two recesses on each side of the shaft with a solid retaining ring around them. The 555 has two pieces held in place with a snap ring and an anti-spin pin in the shaft. You will need to use whichever thrust setup came with that shaft. The anti-spin pin and thrust washer under 1st is the same for both shafts though.

Here is a graph of what the 3.05FD will look like with the 555 gear set and 205/50r15 tires.

Gear   Mph per 1000 RPM   Mph @6500 RPM
----------------------------------------
  1         7.50                49
  2        11.91                77
  3        17.58               114
  4        23.94               156
  5        31.69               206

 Mph             RPM (in Gears)
-------------------------------------------------
           1        2        3        4        5        
-------------------------------------------------
   5      667      420      284      209      158
  10     1333      840      569      418      316
  15     2000     1260      853      627      473
  20     2666     1680     1138      835      631
  25     3333     2100     1422     1044      789
  30     4000     2520     1706     1253      947
  35     4666     2940     1991     1462     1104
  40     5333     3360     2275     1671     1262
  45     5999     3780     2560     1880     1420
  50              4200     2844     2089     1578
  55              4619     3129     2298     1735
  60              5039     3413     2506     1893
  65              5459     3697     2715     2051
  70              5879     3982     2924     2209
  75              6299     4266     3133     2366
  80                       4551     3342     2524
  85                       4835     3551     2682
  90                       5119     3760     2840
  95                       5404     3968     2997
 100                       5688     4177     3155
 105                       5973     4386     3313
 110                       6257     4595     3471
 115                                4804     3628
 120                                5013     3786
 125                                5222     3944
 130                                5430     4102
 135                                5639     4259
 140                                5848     4417
 145                                6057     4575
 150                                6266     4733
 155                                6475     4891
 160                                         5048
 165                                         5206
 170                                         5364
 175                                         5522
 180                                         5679
 185                                         5837
 190                                         5995
 195                                         6153
 200                                         6310
 205                                         6468

Gear Change     RPM drop (change @6500)
---------------------------------------
  1 -> 2            -2405 (to 4095)
  2 -> 3            -2098 (to 4402)
  3 -> 4            -1727 (to 4773)
  4 -> 5            -1590 (to 4910)

Ring gear bolts:

A-525              M10x1.25    70ft.lbs.
A-523, A-543       M10x1.0     65ft.lbs.
A-568              M12x1..25   80ft.lbs.

If Reeves or anyone has something to add please do. Thus far everything has been easy enough on this project that I'm thinking of making more. The hardest part is finding a trans in the yard these days.

[Vigo]

This post and the one you linked to are good stuff! I had a 555 apart one time many years ago but DJs post seemed like almost new info even to me, great refresher.

Your gear chart is interesting stuff..

So, maybe this isnt the thread to discuss merits, but what is the main purpose of this?

I can see it having two purposes: making it easier to get traction in 1st and 2nd, and upping mpg. I can also see it making 3rd much more attractive on the highway for WOT, though i doubt thats a motivating factor.

However, unless im mistaken it is NOT intended in any way to address the strength issues of a 525 like case distortion, etc?

I have an interesting comparison. My honda insight has similar gearing to what this 3.05 fd would be. However, in my case since i have almost no torque to work with, and hills everywhere i go, it ends up meaning that i rarely ever use 5th. 4th is about .8 and 5th is about .6, fd is 3.2, and tires are ~22.5", a bit shorter than 205/50r15.

A 2.2 omni, turbo or not, has a much better torque/weight ratio than my insight, so given the same gearing it would probably work better, but you'd probably still have to use a significant amount of throttle in 5th to maintain speed up a hill.

Anyway, good info!

[cordes]

This post and the one you linked to are good stuff! I had a 555 apart one time many years ago but DJs post seemed like almost new info even to me, great refresher.

Your gear chart is interesting stuff..

So, maybe this isnt the thread to discuss merits, but what is the main purpose of this?

I can see it having two purposes: making it easier to get traction in 1st and 2nd, and upping mpg. I can also see it making 3rd much more attractive on the highway for WOT, though i doubt thats a motivating factor.

However, unless im mistaken it is NOT intended in any way to address the strength issues of a 525 like case distortion, etc?

I have an interesting comparison. My honda insight has similar gearing to what this 3.05 fd would be. However, in my case since i have almost no torque to work with, and hills everywhere i go, it ends up meaning that i rarely ever use 5th. 4th is about .8 and 5th is about .6, fd is 3.2, and tires are ~22.5", a bit shorter than 205/50r15.

A 2.2 omni, turbo or not, has a much better torque/weight ratio than my insight, so given the same gearing it would probably work better, but you'd probably still have to use a significant amount of throttle in 5th to maintain speed up a hill.

Anyway, good info!

Thanks. You have pretty much identified the reasons for my doing the switch.

In order of importance to me they are as follows.

1. I found a 3.05FD setup before I found a 3.50 setup.

2. These days my Omni mainly takes road trips across several states at cruising speed. So this makes sense for my mpgs. Also, we live in the flattest county in the prairie state. You can see the horizon in almost all directions in the winter so I will be able to cruise in 5th at 55-60mph even with this gearing.

3. Traction should not be an issue any longer. Now I will need to worry about making enough power to turn this gear.

I'm actually using the 3.05FD gear set out of the 525 to make a 3.85FD 555 hybrid for my dad who is making a Horizon off road vehicle. I figure this will give him the steepest gear possible. It's not as crazy as I had hoped for, but it is as high as we go. Since everything will be in a 555 case with a 555 diff I think it should stay alive much longer than if it were in a 525 case with off road intent.

[Reeves]

Couple things to change.

I did not need to machine the I.D. of my ring gear at all to fit on my Quaife. It was a perfect snug fit.

4 of the clearance holes on the Quaife almost line up with 4 of the tapped holes in the 3.05 ring gear. I needed to machine the holes about 3mm if memory serves me right.

Then add 8 new tapped holes to the ring gear, for a total of 12 bolts being used, just like a normal 520 ring gear.

I also think that I used the 525 diff bolts in the 4 tapped holes that line up, and then when I added the 8 additional holes, I used the bigger 520 bolts.

Edit: Had some trans numbers wrong above. Fixed now.

[bakes]

Reeves were you running 525 shafts in a 555 case or the otherway around?

[Reeves]

I'm running 555 gearset in a 555 case with 525 3.05FD main shaft and ring gear.

[Reaper1]

Very interesting! I like what I see here!

[Reeves]

520 3.50fd ring gear left / 525 3.05 ring gear right on 520 Quaife diff



520 stock diff bolt left / 525 stock diff bolt right



Pic of the (8) new holes added to 525 3.05fd ring gear. Also shown is (1) bolt in the (4) holes that almost line up (after machining/slottin the (4) of the clearance holes in the quaife)



Pic of the stock 525 diff



Pic of the 525 3.05fd with the (8) new tapped holes added. Note the chamfers.....this was to get by the case hardness.





Pics of the slotted holes in the Quaife.














Found these pics of when I built mine. They may be helpful?

[Vigo]

Thanks for that!!!

[rbryant]

Couple things to change.

I did not need to machine the I.D. of my ring gear at all to fit on my Quaife. It was a perfect snug fit.

4 of the clearance holes on the Quaife almost line up with 4 of the tapped holes in the 3.05 ring gear. I needed to machine the holes about 3mm if memory serves me right.

Then add 8 new tapped holes to the ring gear, for a total of 12 bolts being used, just like a normal 555 ring gear.

I also think that I used the 525 diff bolts in the 4 tapped holes that line up, and then when I added the 8 additional holes, I used the bigger 555 bolts.

Excellent work!

Just so someone doesn't order the wrong thing it should be stated that this was a Neon quaife not a 555/568 quaife. The 555/568 style differential wouldn't have worked because it has a different ring gear design.

Also I think this is limited to the 87/88 555 (or a 520) and wouldn't work on the newer '89+ 555/523/568 transmissions due to the way they changed the main gear in '89 and later transmissions.



The cool thing is that this avoids all of the weak 525 parts! It actually makes something off from a 525 transmission cool (and that is quite an accomplishment).

Is the 525 ring gear the same width/strength as a 520 ring gear?

IIRC the 555 is a little stronger than the 520 but it still shouldn't be an issue. The bolt holes also line up in a safe place to drill/tap what a stroke of luck!


I am pretty sure that the 555 ring gear bolts are actually bigger than the 520 ring gear bolts. I remember this because I accidentally had the impact wrench on tighten and snapped one off from the 523 ring gear when I did my hybrid 568/OBX. I went to use the 568 bolt and it was bigger so I ended up buying a new set for a neon... (PN: 5017180AA $1.50ea) Of course this is assuming that the 568 bolts weren't larger than the 555 bolts....

Are the Lbody bolts the same size as the 520/523 bolts or are they even smaller?

If you used the 555/568 bolts It seems like they would have been larger than the holes in the neon obx/quaife differential that is designed for the 520/523 sized bolt. Did you have to enlarge the holes in the diff or were they already large enough to take a bigger bolt?


-Rich

[Reeves]

Excellent work!

Thanks! And Thanks to my machinist Mike Oaks and to Warren Hall for the re-assembly.

Just so someone doesn't order the wrong thing it should be stated that this was a Neon quaife not a 555/568 quaife. The 555/568 style differential wouldn't have worked because it has a different ring gear design.

Correct. It is a Neon Quaife or as some call it a 520 Quaife. It's the same Quaife you have to use if you are going to run a hybrid 3.50 trans as well (which is what my trans used to be).

Also I think this is limited to the 87/88 555 (or a 520) and wouldn't work on the newer '89+ 555/523/568 transmissions due to the way they changed the main gear in '89 and later transmissions.

I'm not so sure what all they changed besides the sleeve on the main shaft bearing on the diff side and a larger bearing. Were their other changes in 89+ 555's?

The cool thing is that this avoids all of the weak 525 parts! It actually makes something off from a 525 transmission cool (and that is quite an accomplishment).

Is the 525 ring gear the same width/strength as a 520 ring gear?

Overall width is the same. Gear pitch/thickness of teeth is different. The stock 555 and even the 3.50fd 520 has a much coarser design that looks to be more beefy. But, I have quite a few passes on the 3.05fd right now and it looks to be holding up great.

IIRC the 555 is a little stronger than the 520 but it still shouldn't be an issue. The bolt holes also line up in a safe place to drill/tap what a stroke of luck!


I am pretty sure that the 555 ring gear bolts are actually bigger than the 520 ring gear bolts. I remember this because I accidentally had the impact wrench on tighten and snapped one off from the 523 ring gear when I did my hybrid 568/OBX. I went to use the 568 bolt and it was bigger so I ended up buying a new set for a neon... (PN: 5017180AA $1.50ea) Of course this is assuming that the 568 bolts weren't larger than the 555 bolts....

Are the Lbody bolts the same size as the 520/523 bolts or are they even smaller?

If you used the 555/568 bolts It seems like they would have been larger than the holes in the neon obx/quaife differential that is designed for the 520/523 sized bolt. Did you have to enlarge the holes in the diff or were they already large enough to take a bigger bolt?


-Rich

The bolts in the 520 are bigger than the bolts in the 525. Also, the 520 bolts are a finer thread. I used (4) of the stock 525 bolts in (4) of the stock 525 ring gear tapped holes. Then we added the bigger/finer tapped holes (8) to the ring gear and used the 520 bigger/finer bolts. You can see this in the pics I think.

[Reeves]

I added description to my pictures above. These may help.

[cordes]

Thanks for adding all of those pics Reeves. That saved me a lot of work.

[rbryant]

I'm not so sure what all they changed besides the sleeve on the main shaft bearing on the diff side and a larger bearing. Were their other changes in 89+ 555's?

The 89 520/555 has the same internals as a 523/568: That means that the 2nd gear and synchros are totally different. It is the same reason that 88 and older parts can't be mixed with 89 and newer parts when making a hybrid transmission. The 525s were all 88 and older style transmissions so their parts can't be used with a 523/568.

http://www.turbo-mopar.com/forums/vb...e&articleid=80

The bolts in the 520 are bigger than the bolts in the 525. Also, the 520 bolts are a finer thread. I used (4) of the stock 525 bolts in (4) of the stock 525 ring gear tapped holes. Then we added the bigger/finer tapped holes (8) to the ring gear and used the 520 bigger/finer bolts. You can see this in the pics I think.

Ok that makes sense. The 555/568 ring gear bolts are even bigger than the 520/523 ring gear bolts. That was the only thing that confused me because I think you said you used 555 ring gear bolts accidentally.

-Rich

[Juggy]

The 89 520/555 has the same internals as a 523/568: That means that the 2nd gear and synchros are totally different. It is the same reason that 88 and older parts can't be mixed with 89 and newer parts when making a hybrid transmission. The 525s were all 88 and older style transmissions so their parts can't be used with a 523/568.

http://www.turbo-mopar.com/forums/vb...e&articleid=80



Ok that makes sense. The 555/568 ring gear bolts are even bigger than the 520/523 ring gear bolts. That was the only thing that confused me because I think you said you used 555 ring gear bolts accidentally.

-Rich

couldnt u just use the 1/2 gear from the 520 then the 3/4 from the 568...if this were the case??

wish i didnt get rid of my 89 555 since i have a bunch of 568s lol

[Reeves]

The 89 520/555 has the same internals as a 523/568: That means that the 2nd gear and synchros are totally different. It is the same reason that 88 and older parts can't be mixed with 89 and newer parts when making a hybrid transmission. The 525s were all 88 and older style transmissions so their parts can't be used with a 523/568.

http://www.turbo-mopar.com/forums/vb...e&articleid=80



Ok that makes sense. The 555/568 ring gear bolts are even bigger than the 520/523 ring gear bolts. That was the only thing that confused me because I think you said you used 555 ring gear bolts accidentally.

-Rich

Oops, I may have said 555 bolts. Sorry.

Also, the link you sent, it looks like the 1-2 synchro is the only one that is different? So maybe you could use the old 1-2 style synchro stuff in the later trans when using different main shafts?

[86Shelby]

Also, the link you sent, it looks like the 1-2 synchro is the only one that is different? So maybe you could use the old 1-2 style synchro stuff in the later trans when using different main shafts?

That very well may be possible on the 555/520s for 88 and 89; using an 89 multi piece synchro shaft & gears in an 88 case and vise versa. That would not be possible between the 523/568 and 555 due to the different diameter roller bearing on the end.

The nice thing is that all 555s and 568s used the same 3-4 gears and brass, so finding a good one is easier. Synchro parts, likely the slider/ring may be different between the two due to the different fork pads used.

[Juggy]

rich can I mix a 90 523 with a 91+ 568??? for hybrid reasons of course...then id take the 523 gears on the 3.85 to make a quick gearing trans, then i could use a quaife in a 523 geared 3.85 trans...

just trying to figure out what i can do with what "trannys" i have lol

[rbryant]

rich can I mix a 90 523 with a 91+ 568??? for hybrid reasons of course...then id take the 523 gears on the 3.85 to make a quick gearing trans, then i could use a quaife in a 523 geared 3.85 trans...

just trying to figure out what i can do with what "trannys" i have lol

Yes the 523s and 568s are all compatible.

-Rich

[rbryant]

That very well may be possible on the 555/520s for 88 and 89; using an 89 multi piece synchro shaft & gears in an 88 case and vise versa.

I believe that there is some issue with the mounting of the synchros that would have to be resolved in order to mix and match the early and late 520/555 parts. I haven't heard of anyone doing it.

That would not be possible between the 523/568 and 555 due to the different diameter roller bearing on the end.

The nice thing is that all 555s and 568s used the same 3-4 gears and brass, so finding a good one is easier. Synchro parts, likely the slider/ring may be different between the two due to the different fork pads used.

Good point, the shafts are slightly different on the 89 555 and 568.

The gears 1-5 on the '89 555 are the same as the 90 568 (91+ 568s have a shorter 1st gear). The bearing would be a problem on the main shaft if you were to try and put a 555 shaft in a 568. Perhaps the 555 shaft could be sleeved to use the larger bearing but who knows.

Are the synchros the same between the 523 and 568 aswell? It seems like I had them both in my hands once and didn't see a difference.

-Rich