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Guest Message by DevFuse
 

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output Stub Shaft - 5 speed D/R Transmission 1984

stub shaft manual transmission output shafts 1984 5 speed subaru brat gl CV axle lifted subaru 6 lug

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10 replies to this topic

#1 smcclain

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Posted 26 February 2013 - 05:53 PM

The Car:

 

1984 Subaru Brat EA81 Turbo -  5 speed D/R swap (3" body lift, increased tire size)

 

...........................................................................

The issue:

 

1984 5-speed D/R Transmission has a small amount of play (side to side, up down movement) on both of the front splined-stubbed output shafts. on both (passenger and driver) sides of the Transmission.

 

there is a noticable difference between the amount of lateral movement experienced in the front stub shafts (transmission) and the rear stub shafts (rear-differential).

......

i recently put in both new (not remanufactured) front CV-axle shafts, from O'reillys. (yes ive read all of your posts' about the low quality since acquisition).  the axles went 200 miles and developed a significant amount of slop; to the point where i do not feel comfortable driving it.

 

the inner CV axles (inner boot) on both front shafts are now quite sloppy.

 

I popped out the pin and removed the Half shafts from the transmission splines (stub shaft) and found them to have some lateral (side to side) movement. I then compared this to a spare rear-differential i had in the shop and found the the transmission to have a noticable amount more slop than the rear-differential.

 

...........................................................................

The Question:

 

what is the correlation between the amount of slop on the stub shafts and its effect on the CV axles? vice versa?

 

is it possible (or necessary) to tighten the stub shaft and remove the play?

 

does an incorrect alignment increase the failure rate of CV axles?

 

How can i get more life out of my half shafts?

 

any other question and useful information on this topic?



#2 ruparts

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Posted 26 February 2013 - 08:15 PM

The Car:

 

1984 Subaru Brat EA81 Turbo -  5 speed D/R swap (3" body lift, increased tire size)

 

...........................................................................

The issue:

 

1984 5-speed D/R Transmission has a small amount of play (side to side, up down movement) on both of the front splined-stubbed output shafts. on both (passenger and driver) sides of the Transmission.

 

there is a noticable difference between the amount of lateral movement experienced in the front stub shafts (transmission) and the rear stub shafts (rear-differential).

......

i recently put in both new (not remanufactured) front CV-axle shafts, from O'reillys. (yes ive read all of your posts' about the low quality since acquisition).  the axles went 200 miles and developed a significant amount of slop; to the point where i do not feel comfortable driving it.

 

the inner CV axles (inner boot) on both front shafts are now quite sloppy.

 

I popped out the pin and removed the Half shafts from the transmission splines (stub shaft) and found them to have some lateral (side to side) movement. I then compared this to a spare rear-differential i had in the shop and found the the transmission to have a noticable amount more slop than the rear-differential.

 

...........................................................................

The Question:

 

what is the correlation between the amount of slop on the stub shafts and its effect on the CV axles? vice versa?

 

is it possible (or necessary) to tighten the stub shaft and remove the play?

 

does an incorrect alignment increase the failure rate of CV axles?

 

How can i get more life out of my half shafts?

 

any other question and useful information on this topic?

Hi,  i am not sure but ,you may have the wrong size inner cv joints, aftermarket parts stores are notoriously misinformed about  parts for older subarus.  the 82-89 basic cars have either 23 or 25 spline output shafts on their transmissions , there is a difference in the diameter also.  i have heard of folks fitting 25 spline shafts on 23 spline output shafts,, the fit is just like what you are describing,  very loose ,also  they will likely fail and shear the pin because it may be the only thing locking the rotation if this is the case.   some 5-spd trans have the 23 spline shafts and other s may have the 25 spline ,  you need to determine which you have FIRST.  then buy the correct axles  for that fit.  most all turbo 5 spd had the 25's most non turbo 5'spd  had the 23 ,, the original turbo of 84 i am not sure. all original 84 turbos were autos , i think,  but i do not know which size splines they had.   I DO KNOW that ALMOST ALL aftermarket parts lookup systems are very unreliable for what fits what.   my guess is that they sold you 25 spline axles and you need 23 spline,   yes they can be put on but will be loose like you described.   better check ,  or you might be stranded somewhere when it shears the roll pin. 



#3 Numbchux

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Posted 26 February 2013 - 09:32 PM

Hi,  i am not sure but ,you may have the wrong size inner cv joints, aftermarket parts stores are notoriously misinformed about  parts for older subarus.  the 82-89 basic cars have either 23 or 25 spline output shafts on their transmissions , there is a difference in the diameter also.  i have heard of folks fitting 25 spline shafts on 23 spline output shafts,, the fit is just like what you are describing,  very loose ,also  they will likely fail and shear the pin because it may be the only thing locking the rotation if this is the case.   some 5-spd trans have the 23 spline shafts and other s may have the 25 spline ,  you need to determine which you have FIRST.  then buy the correct axles  for that fit.  most all turbo 5 spd had the 25's most non turbo 5'spd  had the 23 ,, the original turbo of 84 i am not sure. all original 84 turbos were autos , i think,  but i do not know which size splines they had.   I DO KNOW that ALMOST ALL aftermarket parts lookup systems are very unreliable for what fits what.   my guess is that they sold you 25 spline axles and you need 23 spline,   yes they can be put on but will be loose like you described.   better check ,  or you might be stranded somewhere when it shears the roll pin.

Well, he said he removed the axles from the transmission, and the slop is in the transmission itself, not the axles.

Also, 25-spline would be an EA82 shaft, which would not be a direct fit in the hub, and would be too long. I don't think it would be possible to install it without making other modifications to prepare for that. So I would rule that out.



That said, play in the stub shafts is really only possible from play in the side bearings of the front diff. This is adjustable, but will effect the gear mesh for the front ring/pinion, and should not change once set. What that means, is those bearings are likely worn out. I have not actually seen this happen (from wear, I saw it happen once in a recently rebuild one, where part of that bearing was left out....), but it seems the only way that a transmission could develop play there.

I do not believe that there is any relation between the axle shafts and the issue you describe.

An alignment would have to be WAAAAYYYY out of wack to put more strain on the axle. Like, crashed, bent, ruined.

An OEM shaft should out-live the vehicle if the boots are replaced as soon as they leak, and the joints are properly cleaned and greased. A reman'd axle is at the mercy of the quality of it's core.....

#4 smcclain

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Posted 26 February 2013 - 09:33 PM

The output shafts on my transmission have 23 splines.

the CV axles purchased are also 23 splines.

 

could there be a differing diameter within the "23 spline" category? although, i don't think this would be my issue, they fit nice and snug on both side.

 

This car was originally a 4-speed auto, which came with the turbo. this was swapped out with the 5-speed D/R.

 

I have come to the conclusion that the axles purchased are the correct size and the roll pins have no unusual wear.

 

i am more concerned with the output stub shafts on the transmission. i am able to move both side with just my fingers, a small amount of side-to-side movement.



#5 smcclain

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Posted 26 February 2013 - 09:45 PM

Well, he said he removed the axles from the transmission, and the slop is in the transmission itself, not the axles.

Also, 25-spline would be an EA82 shaft, which would not be a direct fit in the hub, and would be too long. I don't think it would be possible to install it without making other modifications to prepare for that. So I would rule that out.



That said, play in the stub shafts is really only possible from play in the side bearings of the front diff. This is adjustable, but will effect the gear mesh for the front ring/pinion, and should not change once set. What that means, is those bearings are likely worn out. I have not actually seen this happen (from wear, I saw it happen once in a recently rebuild one, where part of that bearing was left out....), but it seems the only way that a transmission could develop play there.

I do not believe that there is any relation between the axle shafts and the issue you describe.

An alignment would have to be WAAAAYYYY out of wack to put more strain on the axle. Like, crashed, bent, ruined.

An OEM shaft should out-live the vehicle if the boots are replaced as soon as they leak, and the joints are properly cleaned and greased. A reman'd axle is at the mercy of the quality of it's core.....

 

 

From what i can tell, the adjustment on the outer side of the bearing does not look like it has moved (there is a registration marker which appears to be unchanged).

 

what can be done to fix an issue with this bearing? can it be accessed from the outer-side of the bearing (where there is adjustment)?

 

or is it only accessible by cracking the transmission?

 

 

i would like to hear more information about these bearings and their failure rate.



#6 naru

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Posted 26 February 2013 - 10:55 PM

One of the stub axles on my car has been sloppy for years.

Been tempted to tighten the adjuster,but,have not bothered yet.

Pretty sure bearing replacement requires major surgery.

 

Seems reasonable that a loose inner CV would increase the wear rate of the bearing.

 

Sloppy stub axles can allow the inner CV to operate at a greater than stock angle thus increasing wear.

I would expect this to be a minor effect.

 

Wheel alignment makes no difference except for the ride height adjustment.

Higher ride height=greater CV operating angle=more wear.



#7 ferox

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Posted 27 February 2013 - 12:28 AM

Considering the rpms of even regular driving, any slop or looseness in other components of the drivetrain will prematurely wear out CV half shafts.  I have noticed big differences from worn out transmission mounts.  When my trans. mounts get worn, I noticed that my car will sometimes develop a kind of vibrational harmonic, especially when cruising down the freeway at high speed.  It will take out my CVs prematurely, but when the trans. mounts are solid that doesn't happen.  Sloppy stub shafts would have a similar effect I imagine, but I haven't experienced that firsthand.



#8 Gloyale

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Posted 27 February 2013 - 10:17 AM

It's not the bearing. It's the stubs splining and the spring clip inside that keep the stubs in the spiders.

Do not tighten the bearing. It won't help.

Rear diff stubs are bolted, not clipped, so they tend to not wobble so much.

You problem is with the oriel lays axles, not the trans. If it wear a problem, you'd be puking oil out the seals.

Edited by Gloyale, 27 February 2013 - 10:18 AM.


#9 ivans imports

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Posted 27 February 2013 - 10:37 AM

do not mess with the addjusters the slack you see is on the axle to stub not the stub to diff i have put a oring between the axle and the stub thiss helps and on the justys i glue the axles onto the stubs with ultra grey as they have a problem being very slopy I have seen very loose axles on trans and no problems. Mess with diff preload addjuster and all betts are off thiss is just to sett the slack in the crown and pinion and to tight will fail have 10 broken deul ranges 4 are crown and pinon damage if it has all the gears and works good leave it alone



#10 smcclain

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Posted 28 February 2013 - 01:23 PM

so there is supposed to be a small amount of slop on the stub-shafts from the front differential?

 

there is a different securing method used in the front diff and the rear diff to hold these stubs in?

 

anyone confirm these?



#11 ivans imports

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Posted 01 March 2013 - 10:46 AM

they use a floating shaft in the diff cast housing to cast shaft can have some slop is ok its held in with a internal c clip from inside. And has nothing to do with the berring preload addjusters on the side of case they are to sett crown and pinion freeplay only when transs is out. The outputs can be very slopy and no worrys i have never seen it cause any problems. But have seen many trans ruined by messing with the preload addjustments







Also tagged with one or more of these keywords: stub shaft, manual transmission, output shafts, 1984, 5 speed, subaru brat, gl, CV axle, lifted subaru, 6 lug

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