3.05FD Hybrid trans facts

[TurboGLH]

I mentioned last night in a PM to James that it may be possible to use the 523/568 slider on the early hub to allow use of a early shaft in a 523/568. I don't know for sure, but it is a possibility.

This would allow use of any shaft in any year, with a careful mixing of parts. Including allowing for a 3.05 f/d in a 568.

I mentioned it because earlier parts are harder to find, but with the 3.05 he's kind of locked himself into using 88 and earlier parts.

If anyone has easy access to a 88 earlier and 89+ 1/2 synchro assy, a quick check if the later model slider fits the early hub would give a solid answer.

Also the issue of the larger mainshaft bearing is easily solved by installing the sleeve used on the 523/568 onto the early shaft. It's somewhere around $50 from the dealer, but still avail at this point.

edit: In answer to the above question, yes 523 and 568 synchro's are the same, year for year. 90 is all by itself, with 91+ sharing the same parts.

[rbryant]

edit: In answer to the above question, yes 523 and 568 synchro's are the same, year for year. 90 is all by itself, with 91+ sharing the same parts.

Interesting...

Are the differences from 90 to 91 related to the first gear or something or was there actually a change in the syncrho setup?

Can you change the 90 568 to a 91+ style syncrho or is the different 1st gear a problem?

Thanks,

Rich

[TurboGLH]

Interesting...

Are the differences from 90 to 91 related to the first gear or something or was there actually a change in the syncrho setup?

Can you change the 90 568 to a 91+ style syncrho or is the different 1st gear a problem?

Thanks,

Rich

Related to the unique 90' only 1/2 shift fork/pad/slider assy only, the gear makes no difference. The 90' pads are smaller than the 91+ and chryco upgrades them to a much beefier setup in 91 (the pad it self is larger) and changed the fork and slider to accommodate the larger pad.

[cordes]

I mentioned last night in a PM to James that it may be possible to use the 523/568 slider on the early hub to allow use of a early shaft in a 523/568. I don't know for sure, but it is a possibility.

This would allow use of any shaft in any year, with a careful mixing of parts. Including allowing for a 3.05 f/d in a 568.

I mentioned it because earlier parts are harder to find, but with the 3.05 he's kind of locked himself into using 88 and earlier parts.

If anyone has easy access to a 88 earlier and 89+ 1/2 synchro assy, a quick check if the later model slider fits the early hub would give a solid answer.

Also the issue of the larger mainshaft bearing is easily solved by installing the sleeve used on the 523/568 onto the early shaft. It's somewhere around $50 from the dealer, but still avail at this point.

edit: In answer to the above question, yes 523 and 568 synchro's are the same, year for year. 90 is all by itself, with 91+ sharing the same parts.

I would strongly agree with your assessment. After digging into a few transmissions now, I can see where will will be able to make combinations that will allow for massive parts interchange and keep many more of these units serviceable. I certainly won't be passing up the opportunity to pull the synchro assemblies out of 525s any longer.

[rbryant]

Related to the unique 90' only 1/2 shift fork/pad/slider assy only, the gear makes no difference. The 90' pads are smaller than the 91+ and chryco upgrades them to a much beefier setup in 91 (the pad it self is larger) and changed the fork and slider to accommodate the larger pad.

Does this mean that if someone is doing a hybrid '90 568 with a 91+ 523 and they should swap out the 523 shift fork/pads/slider assembly into the 90 568?

If so I wish I knew about that a few years back...

-Rich

[TurboGLH]

I would strongly agree with your assessment. After digging into a few transmissions now, I can see where will will be able to make combinations that will allow for massive parts interchange and keep many more of these units serviceable. I certainly won't be passing up the opportunity to pull the synchro assemblies out of 525s any longer.

I would look myself, but I don't really do car stuff anymore, plus my dads garage is in disarray while we do the finish work on his new addition.

Does this mean that if someone is doing a hybrid '90 568 with a 91+ 523 and they should swap out the 523 shift fork/pads/slider assembly into the 90 568?

If so I wish I knew about that a few years back...

-Rich

I would. Not necessary though. If you used the full 90' synchro's and the 91 523 shaft, you have a 90' 523/568. If you had switched the sliders, you would have a 91' 523/568. The 90 pads are NS1 *i think*, it's hard to keep track, so I could be mixing them up with another year/gear.

If you ever *have* to pull the gearset for some reason.....like changing a shift fork pad. Take the time, if you can get new 91+ 1/2 pads and swap out the slider, should last longer than the 90' ones did/will.

If i recall correctly, the 90' 1/2 pads are closer in size the the 3/4 pads, vs the much larger and more durable 1/2 pads used 91+

[cordes]

I'll be adding the following information to the OP. If anyone has the 555 and 520 bolt specs for sure please post them up. I've taken this info from my 90' FSM

Ring gear bolts:

Ring gear bolts:

A525               M10x1.25   70ft.lbs.
A-523, A-543    M10x1.0   65ft.lbs.
A-568              M12x1..25   80ft.lbs.

I think I'm just going to use the 525 bolts for my ring gear after seeing this info. If anyone has a different opinion based on the thread pitch let me know.

[rbryant]

I'll be adding the following information to the OP. If anyone has the 555 and 520 bolt specs for sure please post them up. I've taken this info from my 90' FSM

Ring gear bolts:

Ring gear bolts:

A525               M10x1.25   70ft.lbs.
A-523, A-543    M10x1.0   65ft.lbs.
A-568              M12x1..25   80ft.lbs.

I think I'm just going to use the 525 bolts for my ring gear after seeing this info. If anyone has a different opinion based on the thread pitch let me know.

It probably doesn't really matter. The torque on the fine threads will be more accurate and you will get more threads engaged so the fine thread is probably slightly better. Considering that they also upgraded the number of bolts on the 523 diff it should be fine.

The larger M12 bolts were probably required because they are both holding the ring gear on and compressing the diff case on the 555/568.

Use loctite on either fine or course thread M10 bolts and all should be good.

One other practical reason to use the 523 bolts is that if you are doing a side by side swap you will have enough 523 bolts but not enough 525 bolts to do the job.

-Rich

[cordes]

It probably doesn't really matter. The torque on the fine threads will be more accurate and you will get more threads engaged so the fine thread is probably slightly better. Considering that they also upgraded the number of bolts on the 523 diff it should be fine.

The larger M12 bolts were probably required because they are both holding the ring gear on and compressing the diff case on the 555/568.

Use loctite on either fine or course thread M10 bolts and all should be good.

One other practical reason to use the 523 bolts is that if you are doing a side by side swap you will have enough 523 bolts but not enough 525 bolts to do the job.

-Rich

Thanks Rich. That is pretty much what I was thinking. I have a bunch of 525 bolts lying around so I will probably use those.

[135sohc]

The 523/568 1-2 synchronizer slider does fit the 87/88 555/520 1-2 synchronizer hub. Not sure about an 89 since I dont have one of those yet but I bet its the same.

Not totally out of the woods though. Would have to use the 87/88 1-2 gears and that cuts out using a 92+ 523 or 568 gearset since the 1st gear changed on the 568 and the 92+ 523 is of course is its own unique gearset.

[cordes]

That's one more part that will work though. Thanks a ton for the info.