INFO: I have a 1989 Dakota 4x4 with a 4-speed auto. I had the reverse go out all of a sudden. So after disassembly the problem was that the overrunning clutch thrust bearing self-destructed. I was able to buy a A500/A518/A618 overdrive replacement kit. I am using a ATSG and factory service manual to help with my rebuild. When I disassembled the original direct clutch pack it had 6 frictions/5 steels. Now for me to get a reading that is on the overdrive piston thrust plate selection chart, I have to install 8 frictions/7 steels.

QUESTIONS: Was this an incorrect part I am installing?
Will this thing work properly?
Is this normal?

Any help will be much appreciated. I don't want to have to pay someone to rework my work.

Bill

PS I didnt have any luck looking up A500 rebuild on moparts search engine.

http://atsg.biz/

there is a manual and video available for this trans...

also i will post an explosed view of the trans...

sorry reread your post....you have the manual

the number of frictions and clutches depends on application of the overdrive...

I have the exploded view, Don't have the video. how do I tell exactly what trany this is?
I was hoping the get an experienced transmision guy willing to help answer my questions.
Thanks for your input. Bill

I did an 518 earlier this year..no trans expert...

someone will come along with the right answer..

I guess you didnt run into any thing like this on your rebuild?

the video actually was for the 500, they are basically the same as the 518 except for the number of plates and clutches in it.

the video does discuss the difference in the od units as to where the snap ring is determines how many plates/clutches the od unit takes.

my 518 took the 8 disc/7 retainers....i was able to get the correct reading to order the correct spacer...

Maybe you got the wrong kit? Did you use the tags on the trans to help ID what kit might be required? Not sure if it was required but I copied all the info down for our parts guy when i rebuilt a 43RE at work.
Do do you have the overdrive alignment tool? Without one you will have great difficulty

In the ATSG book it gives the dimensions of the gauging tools. I was able to make them, I am a machinest.

I did compair the new replacement parts with the old befor I returned them in for a core. They didnt look or measure any different.

Bill

Are you using the original steels and reaction plate? If they are changed, the is a .130 difference between first and second design reaction plates and a .015 difference between the steels.
If you have the correct spacing and a thrust plate of the correct dimension, you should be ok. The more plates/steels in the pack increases the friction surface area and will stand up to hard usage longer.

I am using new steels(.069) and frictions(.060) the original measure frictions (.060) steels (.070)
I had to add 2 frictions and 2 steels to the original 6 frictions and 5 steels. By doing this it allow me to pick the correct overdrive piston to hub shim and mach the dimension in the chart given.
I under stand that the more plates/steels in the pack increases the friction surface area and will stand up to longer and hard usage.

But will this work correctly?
Is this normal in this application?

Bill

The factory way of measureing rear piston clearance is a PITA. To do that just pull the wire snap ring out and put the rear piston in to the OD unit how you it would be when running and use a feeler gauge between the top steel and the piston. You are looking for about .090 - .110 clearance. This is way easier than setting up all those gauges and stuff the factory recomends.

Also for the # of clutches. I will always measure the total thickness of the fat plates and the clutch plates and steels and shoot for that same number thickness when adding clutches. I have done a bunch of these this way and have not had a problem removing the fat steel plates and adding more clutches and steels. Also another trick I use in hi-po re-builds is to take the wavy snapring out of the OD clutch pack and install 2 flat ones. It will slip less. Another trick is to take and drill the OD feed hole one size bigger for a faster apply, this hole is found in the "cylinder" the rear piston rides in. I drill that hole one or two sizes bigger depending on how hard I want the OD shift. The only way to get overlap in the OD unit is with not enough clearance in the OD clutch pack or the Direct pack, it is hard to set up the direct pack without enough clearance because of the way it is assembled, you have to compress the big spring and basically dissengage that pack to install the snap ring and you can't really do that if there is not enough clearance because the snapring sits down in a gully. Also to line it all back up on assembly just use the intermediate shaft, before you put the 904 half of the tranny back together. Almost forgot one more trick I use to make the OD react faster to when you want it to shift is to put a blocker rod in the VB OD acumulater in place of the spring. This mod makes the OD turn on faster once the solonoid is energized, less lag after you flip the switch not a harder shift.

So you are saying that the shim behind the thrust bearing is used to adjust the overdrive piston to plate clearence (.090-.110)

Will changing the number of clutches effect the disengagement of the direct drive while the overdrive is being engaged?

I have made my decision. I will use the direct drive with 7 steels/ 8 frictions. This set up was checked with the chrysler test method AND the feeler gauge method in the above post. I also did a lot of extra measurements of the combining parts. It all seems to check out to the .090-.110 numbers. When I complete the install and have the test results I hope to post a follow up.
Thanks Bill

If you can compress the direct clutches enough to get the snap-ring in then you have enough clearance to disengage them. You can put as many as you want in there and if you can get the snapring in with out forcing/bending it or something then it will release enough. To adjust the clearance I play around with different clutches, snaprings and steels in the OD clutch pack.

Thanks for the reassurance.

Got it together. Filled with fluid, started it up, shifted it through the gears. Sounded good. I am letting it sit untill I can get exhaust on it, befor I drive it.

There was a factory "Hot Line Newsletter" years ago around that year where they changed the number of clutches in the Direct clutch and it caused a slippage in reverse in a trans one of my tech's rebuilt. It was fine in drive because of the overrunning clutch in the overdrive unit. I wish I could look it up for you but I am off work rightnow because of back surgery. Ron

Got the exhaust made. Had to re-adjust the throttle rod. Haven't been on the highway to test 4th, No insurance and expired plates.

Took a 100 mile trip All is well.