Reverse pops out...... GRRR

[kaptainballistik]

Well, Im at the end of ideas....

My VR-4 has a w33 series "Forest" ratio Group N box.

I was getting severe crunching in 5th and reverse would crunch badly and pop out under load unless I held it in gear..And sometimes that didnt work.

After the last Rally reverse refused to engage so I replaced 5th gear with a EVO3 unit as well as the Brakecluch and the dropgear. I also used a later "Aussie" 33 series shift fork as I didnt want to pull the box out of the car and fit the EVO 3 shiftrod.

All fitted and would "Benchshift" with no problems ( The side plate was off!) The gear lock nuts were tight when removed. And I tourqed those suckkers up. There was no apparent shaft slop either.

The car now doesnt crunch in 5th but reverse pops out. If you load up the trans it doesnt pop out. Try to move.... Grindage. And you cant just hold it in ( Sometimes). If you slip the cluch you can use reverse...barely.

I was thinking the shifter didnt have the correct ammount of movement range, I removed the Shift cable off the horisontal change lever when it was in reverse and I had extra travel..... So its not a shifter travel issue.

Before I rip this gearbox out...has anyone got another possibility?

 

[kaptainballistik]

Ok, plot thickens... Ive got more than enough linkage travel, Ive got rid of all the slop and is still wont engage ( It will move the car then pop out now!)

Ive stuck a EVO3 5th gear on... Could there be a difference between a early (Evo1-2) and a later (Evo3) Side cover which is causing the gears to not engage (Shift fork fouling?)

 

[kaptainballistik]

Ok... I man'ed up and Pulled the gearbox out... :/

Nothing obvious /ubbthreads/images/graemlins/dunno.gif

The only thing I can find is there is a bit of slop in the Reverse linkage ( The bit that sits on the shift rods has about 1 mm of clearance ) whicg allows the reverse gear to walk..

Anyone seen this before? Besides that the gearbox is clean ( Gotta love redline shockproof heavy..) The only other thing I can think of is that the rRedline has cleaned the crud out of the gearbox, Which included the usual shiftrod gunk that took up the play..

Because the issue became serious after I started using it!

 

[Barnes]

Can you post pictures of the reverse idler and the 1st/2nd gear slider?

 

[Terry Posten]

I was under the impression that heavy shockproof is bad for the sycnros.

Other than that, no clue.

 

[kaptainballistik]

Ill post a pic Tomorrow when I have with me a camera that is better than the Phone camera!

I

 

Shockproof should be used for transfer case and diff, not transmissions. The high paraffin content is bad for syncros engagement and internal oiling system. And its GL-5 which is also bad news for your brass syncros. If your lucky the GL-5 additives won't have caused to much damage yet and when you flush it out everything will be okay. Make sure you drain it while its warm/hot since heavy shock proof is so thick. Throw some MTL/MT90 in there and things should improve. You'll probably want do flush it again in a few months to get the shockproof residue out.

 

[3rdstrikedsm]

Sounds like the engagement teeth are worn on the gear and or the slider.

 

[3rdstrikedsm]

Also how much hp/tq does this make? Is there an als on it?

 

[kaptainballistik]

This thing has NO grunt. It runs 14PSi in rallytrim, doesnt come on boost till over 4200. Its got issues.

BAH, just use cornerspeed (Its working sofar and Its now got an Autronic which even in its untuned state is a revelation) Only trick bits are the EX Works turbo and dump Pipe (And the dump is a work of art...)

Its Stock as a rock RS gearbox and motor. It gets bumped up to 17psi for a Khanacross.

The reason Im using Redline is that it seems to prolong the life of the Gearboxes in rally use. The Drop gear (Which is the strength issue) seems to take less of a hammering. And it did stop 5th gear crunching.

But on the other hand the fact that all the sludge has gone from the gearbox...Thats disturbing.

 

[3rdstrikedsm]

The reason I ask is because I have a friend who is a head mechanic on an evo rally team here and they go through a trans every 2 or 3 events due to the extreme torque ( 465 ftlbs) and heat which actually pushes the bearing mount area where the race goes in to the caseing apart and it will then change the preload to the point where the trans is actually trashed or at least the case, I wonder if this may be a problem for you?
They are constantly on the als as well which also contributes as well.

Also this is in a dogbox gear set so add helical and the weak gear box you are using this could be something worth looking at.

 

Whether it stops your crunching or not, high shock proof is a GL-5 and will destroy your syncros given enough time. Our trannies are GL-4. It is fine for your diff and transfer case (which can use GL-4 or 5 since they don't have brass), but not design nor intended for transmissions.
Reason being is the shock proof line of red line uses paraffin (wax) for shock proofing. It builds up a film layer on top of all components. For diffs/trans cases this is fine since everything is in constant engagement which keeps it from building up thick layers. On the other hand it will build up thick in setups with syncros since they aren't constantly engaged. The film will continue to build up thicker and thicker until you run into issues like your describing where the thick film of wax allows it to keep sliding out of gear. Other reason they aren't designed for transmissions is the paraffin will eventually clog up internal oiling holes. That isn't an issue on ours since they are splash oiled if I remember correctly, but can be on some cars.
As for your sludge magically disappearing, its probably suspended in the paraffin instead of settling to the bottom like it would in normal gear oil.
MT90 is the thickest that is really recommended for our transmissions. Its a 75W90, but you could probably check and see if they have something a little thicker (with GL-4 rating) if you wanted the extra protection, rather then going with the shock proof.