Who's had fifth gear pop out before ? (sr20de)

[Spyke]

P11-144 gearbox with a quaife diff. See if you can extract a quaife off one of the NPOC lot that isn't using it as a paper weight.

 

[Prim gt]

Am i right in thinking that the p11 144 boxes are 15 percent stronger too ?

 

[Spyke]

They are the strongest SR box.

 

[Prim gt]

Ok thank's Spyke and the other guys,i have a look around,hopefully find something worthwhile.

I will report back in my project thread soon......Got a couple of jobs to do first !

 

[Sam]

9.754% stronger

 

[Mad Maru]

Sounds like synchro has worn do you drive with hand on gear lever whilst driving? As has been a common issue found on cars driven with hand on gear lever putting strain on the synchro


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[rowdy-GTi]

You don't need stronger. Yours lasted 152k.

 

[Prim gt]

Fair point,it lasted well i suppose,i only just started to rest my hand on the knob since installing my short shifter,like a couple of months ago.

 

[CoV]

Sorry but resting hand on gearstick?? How could you pinpoint that as the cause to a faulty gearbox. So many other things could cause it in the time it takes a gearbox to show faults.

Plus are the syncros not just for rev matching the gears when changing?

 

[Andy Sunny Gti]

Had the sr18de lsd box on my Nissan Sunny gti. Had the 5th gear pop out issues and just replaced the gears from a UK sunny gti box. 4 years later still running fine.

 

[Sam]

Sorry but resting hand on gearstick?? How could you pinpoint that as the cause to a faulty gearbox. So many other things could cause it in the time it takes a gearbox to show faults.

Plus are the syncros not just for rev matching the gears when changing?

Its speculation mentioned on the SR20 Forums.

5th gear and its causes are all over the US forums, I've stripped down a box and witnessed the early signs of wear, I've just swapped them out for good parts from another box.

Here is the selector arm, one part of the cause.

good on the left bad on the right

this translates into extra movement that will allow it to pop out, coupled with the worn synchro and gear.

How to recognize if a transmission has 5th gear pop-out by looking inside

Facebook album permalink (in case the images don't show up in the future).

Once you have the case open (for those directions see section 4) you'll be looking at the gear stacks. I've labeled the 5th gear in this picture with purple.

I have this gear and the assembly above it on my desk that I've taken pictures of to help us out.

This is the 5th gear followed by the brass synchro and then the coupling sleeve. (From bottom to top).

Here is the stack again as they sit in the transmission.

Here is what it looks like with the coupling sleeve disengaged. My hand doing the job of the shift fork.

This is what it looks like with 5th gear engaged.

Here's what it looks like with the selector lifted off.

And with the synchro removed.

All three pieces separated.

This is the two main pieces of the coupling sleeve and hub assembly. Normally two ring springs and three retainers hold it together and allow them to slide up and down a bit.

Here they are together. The three open spots are where the three retainers go.

Here are the dog teeth on the coupling sleeve that have been torn up causing 5th gear pop-out.

Here they are again. Torn up. Chipped teeth.

More carnage.

Here is what the other side looks like that hasn't seen any use in it's life. This is what it should look like more or less.

More pics of the good stuff.

Here are the dog teeth on the 5th gear itself all torn up causing 5th gear pop-out.

Another picture of the beat up dog teeth. You should see now that with all this material gone the teeth don't have much left to hold onto.

Here is my brother's 5th gear that we replaced ahead of time before it could get 5th gear pop-out. It looks a lot better.

Again.

Good one on the left, bad on the right.

Here is the bad one again. You'll notice the distance between the gear teeth and the dog teeth is very small. Maybe 1mm at most.

The redesigned gear will have about 2mm between the gear teeth and the dog teeth. Basically they sit up higher. This means they penetrate deeper into the coupling sleeve and do not loose contact and slip or grind themselves up. Take a look back at the picture showing both gears next to each other. You'll see neither is the redesigned gear even though they both came out of 1994 transmissions.

 

[Mad Maru]

Sorry but resting hand on gearstick?? How could you pinpoint that as the cause to a faulty gearbox. So many other things could cause it in the time it takes a gearbox to show faults.

Plus are the syncros not just for rev matching the gears when changing?

Firstly I never pinpointed that as a cause g20.net and NPOC have had this issue and the cause was as stated due to stress put on the synchro by lazy driving with hand on gear stick. I'm sure the owner has just also stated he has most recently been doing as I mentioned. But hey what do several members from other forums who have had had the same issue know?


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[Prim gt]

Sam,that must be it then as in the pics,as i get loads of movement in fifth before it pops out,in any other gear,the stick does not move at all !