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1G Transmission Failure Question

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a91eagletalon

Supporting Member
278
13
Aug 24, 2005
Norfolk, Nebraska
OK so this is a 100% new build with a 23 Spline 1g trans I purchased from a guy that had it built already.
Gear sets are faceplated from liberty Gears cryotreated and shot peened.The gears are evo3 1st with new evo3 input shaft, stock dsm (but new) 2nd, evo3 3rd and 4th.syncro 5th and reverse
4 spider center diff from Jacks, new seals, bearings, steel forks, faceplated 1-4,

My question is I had instant failure of fourth gear. the second I put it in gear for the very first time wile moving it exploded. Was not under a pull just normal driving testing it out. this build had only like 3 miles on it before it broke.

My question is what do you think caused it I will attach pics of the gear sets new well what pics I have and also I will attach pics of the broken trans.

Let me know what you guys think
New pics
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That's a typical failure from making lots of power and trying to powershift into 4th.

4 possible situations.
1. Sometimes it just sucks to suck.
2. You are not telling the whole story and tried to really jam gears while making lots of power
3. Foreign object damage
4. Trans wasn't really all new, and 4th/intermediate shaft was allready used up and about to fail.

I'd be mad as hell if that was my trans I paid good money for. Not because of the failure, because of the pictures. It looks rusty as hell, and dirty prior to assembly. 2nd and the intermediate shaft look used. Perhaps the intermediate shaft had some cracks in 4th gear, and was ready to fail when the trans was assembled.

Good news is it should be like a $500 fix. New shaft, 4th gear, and have libery re-faceplate it.
 
That's a typical failure from making lots of power and trying to powershift into 4th.

4 possible situations.
1. Sometimes it just sucks to suck.
2. You are not telling the whole story and tried to really jam gears while making lots of power
3. Foreign object damage
4. Trans wasn't really all new, and 4th/intermediate shaft was allready used up and about to fail.

I'd be mad as hell if that was my trans I paid good money for. Not because of the failure, because of the pictures. It looks rusty as hell, and dirty prior to assembly. 2nd and the intermediate shaft look used. Perhaps the intermediate shaft had some cracks in 4th gear, and was ready to fail when the trans was assembled.

Good news is it should be like a $500 fix. New shaft, 4th gear, and have libery re-faceplate it.

1.Yes it dose Suck to Suck
2. You are getting the whole story if i broke it under a hard pull i would know why it broke.
3. Possible
4. I cant confirm it was new everything else is new.

And yes I am mad as hell. You bring up some good points I should have inspected the pics a lot better.

I just wish there was a clear cut reason why it broke. It is what it is ill get new parts coming and get it back on the road again.

And just to confirm the intermediate shaft is from the dsm transmission right 92-99
 
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1.Yes it dose Suck to Suck
2. You are getting the whole story if i broke it under a hard pull i would know why it broke.
3. Possible
4. I cant confirm it was new everything else is new.

And yes I am mad as hell. You bring up some good points I should have inspected the pics a lot better.

I just wish there was a clear cut reason why it broke. It is what it is ill get new parts coming and get it back on the road again.

And just to confirm the intermediate shaft is from the dsm transmission right 92-99
Yes that looks like a 92-99 intermediate shaft. I would also just get normal dsm gears and not the Evo gears.
 
Did the 3rd/4th shift fork get properly clearanced so it wouldn't hit the face plates? Using an evo 3 fork needs modification. As well, if have to look at more pictures of the stuff on a PC to see closer than looking at this on my phone. The gearset spread, could be a shimming issue , could be a contact issue at the shift fork, it could be a beam weld for a face plate jamming on the hub causing a lockup problem. Either way, it could have been a list of several failures including either an intermediate shaft flaw or gear flaw.
 
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Did the 3rd/4th shift fork get properly clearanced so it wouldn't hit the face plates? Using an evo 3 fork needs modification. As well, if have to look at more pictures of the stuff on a PC to see closer than looking at this on my phone. The gearset spread, could be a shimming issue , could be a contact issue at the shift fork, it could be a beam weld for a face plate jamming on the hub causing a lockup problem. Either way, it could have been a list of several failures including either an intermediate shaft flaw or gear flaw.
That I am not sure of I can look and see if you tell me what to look for and i can take a couple more pics with the case off.
 
That I am not sure of I can look and see if you tell me what to look for and i can take a couple more pics with the case off.
Take the case off and pull the clusters so we can take a look at the fork and the gearset.
 
here is it taken apart. Now when you say clearance do you mean between the slider and the fork. And or the dog teeth and fork
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I mean specifically the dog rings on the gears contacting the shift fork, just like the machined down area on the shift fork. Now, is that fork machined down from contact or is it actually ground down to clear before this incident.

Can you rotate 4th gear on the input shaft smoothly by hand? 3rd too?
 
I mean specifically the dog rings on the gears contacting the shift fork, just like the machined down area on the shift fork. Now, is that fork machined down from contact or is it actually ground down to clear before this incident.

Can you rotate 4th gear on the input shaft smoothly by hand? 3rd too?

Yes they rotate smooth everything clears I don't see any indication where the dog ring contacted the fork
 
Well I see marks on the fork , take a closer look.
 
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