rare failure point 525-555 worth mentioning..

It might seem I'm the only one to have this failure thus far

I even discussed it with onerippinturbo2 and he had never seen it ..
so must not happen often..

the little screws that hold the shift forks to the internal rods .. they are threaded for part of their length and the end is like a pin that fits into the hole in the rod..
- works fine ..

until repeated shifts crack the bolt where the pin shaped tip and the threaded section meet..
this means the unthreaded pin tip that fits into the rod ..
CAN DROP OUT . and fall into the gear parts as the threaded portion is screwed into the fork

something we want to avoid .. more so as we invest more in the transmissions..

so a fix might be a high grade bolt with a longer thread and a small thread tap .. real cheap insurance
better to drill out the broken bolt than replace the transmission

in my 555 it bounced along the top of the gearset until it got to the ring & pinion where it went through
- cracked the case at the bearing but didn't hurt the hardened gear parts

bolt tip looked like chewing gum in diff

if your power shifts have a "hammer on anvil" sound to them you need to know this ..

The sound to look for is a good tip. I don't think it's common, but I've certainly heard of this happening to a few people over the years. I've never had a problem with it, but I could see how it would only take a small problem with quality control on that one piece to ruin a batch of transmissions in the long run.

maybe Reeves or Warren Hall but someone mentioned this before. Unless you can make a new pin/bolt with a zero clearance fit going into the rod this scenario will be likely to occur. The rod hole and pin being a loose fit allows for them to hammer on each other over time and fatigue the pin/bolt until it snaps off. It has been awhile since I have looked inside a 520 series and going off memory due to the design there is not enough metal to drill and install a coiled spring pin like the 523 series uses.

Edit: http://www.turbo-mopar.com/forums/sh...ear-shift-fork

I'm thinking a small insert to reduce the inner diameter of the thread in the fork and a simple straight pin threaded it's entire length and the fork insert & rod threaded as one piece with the tap - then install a pin that no longer is able to drop out..if it breaks

the strength need only be that of the existing pin tip as it is now

the hammer on anvil sound is me slipping the clutch only enough to reef the thing into the next gear ..it's the "clacking" of the gearsets banging into each other .. so I pull second and push third ..eah kinda hard

there was a time engines and transmissions were "disposable" - I didn't treat them well so I broke a lot of stuff
this issue I haven't seen mentioned in the ten-ish years I've been on "the sites"

interesting to know the screws in the 523 & 568 are different .. I haven't been inside one yet

Positive shift stops to prevent overstressing the internal components?

Is there enough room to install a coiled spring pin ? Those little suckers are the devil if your servicing a 523 series, they like to fall into the bottom of the case when your putting them back in but I have never noticed them having worked their way loose. I only drive them in until they are flush on the bottom side of the shift forks and lugs and never noticed them poking further through at a later time.

Quote:

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Originally Posted by Reaper1

Positive shift stops to prevent overstressing the internal components?

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Not a bad idea.

I have never look at other FWD transaxle family other than new process/new venture units. So many cheap cut corners on the little things, these things were made to last 150k and be tossed.

"So many cheap cut corners on the little things, these things were made to last 150k and be tossed."

new bearings .. everywhere is the biggest secret to keeping these alive

--old and sloppy equals soon to be busted...

fist one I rebuilt (first trans ever re n re actually) a 525 was UNBREAKABLE for the six years I had it
@ - 12# log motor..

input shaft was so tight I had to forcibly turn it with a ratchet as I put things together
when I first started the car it idled SLOW for about a min as things got pushed into place

only upgrades were a turbo 1-2 fork and turbo spider gears for the diff and 5w-30 oil
-305 carb car trans

one of the guys at the local dealership had a charger with a spider gear chunk that went through the bellhousing and out the front towards the rad..

I said to him .. "good thing it didn't go the other way"

-been considering a nice piece of 1/16 steel plate for under the carpet since ..as I have one saved for just that reason as I don't have a lot of faith in aluminum casings ..hell we used to replace the o-e bellhousings with stamped steel scatershields ..