Gearbox issues

[Super Top]

I've read some things about the gearboxes of the HSG's are not very strong.
Is this true and what are the parts that usually break or wear out inside the gearbox?

Why am I asking? About a month ago the gearbox of my manual HSGR went.
I't won't go into second gear. And in the exceptional case it goes into second you can't get it out anymore.
Also it kicks out of gear when driving in reverse.

I learned from the dutch Mitsubishi community that the previous owner used the car for drags and sprint races.
Something the previous owner ofcourse didn't tell me.

When I took the gearbox off I let out the oil, it was completely black and smelled bunt.
I brought the box to a gearbox rebuilder in my neighbourhood. To check what's wrong with it.
At first we could not find much.
He found out that gearshift fork of second gear was worn out on one side.
The synchro's were a bit worn but not excessive. Same story for the hub, sleeve and keys that select second gear.
It all gets replaced just to be sure.
We could not find anything about reverse kicking out of gear.
I hope with replacing all of the bearings it will stay in gear again.

What are your experiences with these manual boxes?

Mine is a manual HSG-R has 137.000km's on it and is still completely stock.

 

[blackvr]

They are not really any different to the Galant VR4 thru to Evo 3 gearbox. In fact the Evo 3 gearbox is practically identical to the HSG gear box. I have just rebuilt a HSG gearbox last week, and I notice these boxes have the updated 1st/2nd steel shift fork with the plastic insert rubbing block. With hard shifting , these distort or even break. This will give problems selecting 2 nd gear. Replace it with a new one. Have an extra good look at the synchros and the wear commonly found on the back of the gear. This then prevents the double synchro from baulking properly.
I've had another HSG with reverse issues, and to be honest, it was never fully resolved. Never had issues with an Evo 3 gearbox, and they are essentially identical. Just have a extra good look at the selector arm.
Just make sure the gearbox guy shims the motion shafts correctly... this tends to be at the start of all issues if not corrected ! And I havent found one of these gearboxes that has been even close to being correct in shimming from the factory !

 

[Super Top]

Thanks blackvr!
I'll pass this information trough to my gearbox guy.

Indeed the exact same problem with my gearbox.
Distorted shift fork, on one side the plastic inserts were completely gone and the metal of the fork was worn out to blank metal.

Too bad to hear that the reverse issue is quite of a mistery. I'll check the selector arm.

How much the same are the Evo3 en HSGR boxes. I've read that they aren't interchangeable because of different final drive ratio's.
Evo3 boxes seem much stronger. They also have a friction center LSD in stead of the viscous center LSD in the HSGR.

I'm also a bit worried that the gearbox won't hold it when upgrading the engine. If it already breaks like this with factory spec. how long will it hold when you pull some more horses out of the engine.
I know everything is determined by how it's being used. And my HSG is really being abused by the previous owner but still.

 

[blackvr]

You havent broken the gearbox !! They are fairly strong ! In all likelihood, the shimming on the motion shafts are wrong due to worn bearings... leading to selection issues. The update plastic insert 1st/2nd arm is just wrong for competition work, and you need the original Evo 3 solid selector arm. The slider hub has probable excess wear as well. They are easy to source new as a clutch slider kit with new synchros.

Evo 3 boxes also have viscous front LSDs, and open centres and plate LSDs.. Just buy a Kaaz mechanical front LSD and replace the viscous. The driveshaft cup will be different to the viscous, but doesnt present a problem. Plenty of people will want to buy the viscous cup though ! You will be able to transfer the Evo 2/3 gearset into your HSG bearbox. Just retain the HSG final drive .. easy ! We put a lot of torque thru them in our competition work, and with SOME sympathy, they stand up ok

 

[warbo]

Think mine is the one discussed above with reverse gear issue. Had box fully rebuilt. Reverse gear eventually continued to jump out of gear under load again. Cables were fine. Gear was definitely being selected. Eg, removed switch balls and springs. All ok that far. Thought stuff it and continued to drive rvr daily for a year. Just had to be careful where parked. About to remove gearbox for full strip. I am expecting to see shoe on reverse gear selector broken, arm bent, or the cast part moving independently on the rail. Let me know how u go. I really want to get this old b!tch going again.

 

[grndsm]

I am pushing around 450hp, running 11's on a stock Summit (non turbo RVR for you guys). The only thing I upgraded was the center differential (I am using ShepRacing 4 spider gear unit) and a DSM viscous coupling (which is roughly 50% thicker than the original VC).

Aside from the center diff, hese trannies are VERY STONG!!! They are vertically identical to AWD DSM trannies. But they do no have EVO 1-3 parts, like steel forks .

As for your problem, there are two "ends" to a gear selector rod:

One is what most people talk about: big fork that moves the slider to lock the gears

The other one is much smaller, it is on the other end of the rod, that is where motion comes from. Because it is so small, even the smallest imperfections get amplified on the other end.

I would check that mechanism for wear and/or damage from bending.

Also make sure that all of your detent balls and springs are functioning as intended.

There isn't much to reverse. If it was popping out it could be:

- bad detent
- bad actuation mechanism
- loose "fifth gear nut" (was it loose?)

 

[warbo]

Fifth gear nut tight. Springs n balls in detent ok. Cables are ok. Reverse gear easily engages, but jumps out under load . Grrrrrr.

 

[rexhunta]

Looks like i've done something to mine tonight.

Came onto highway first to second, slight clunk, but it kept powering so thought must've slipped.

Now, won't select first, if it does go into first, it bounces right out. If i start off in 2nd it's okay, will change to third smoothly, but won't downshift from 3rd to 2nd.

Also just worked out my reverse stutters like a locker. Am I effed or is it common thing that i can source parts for and just baby for a bit ?

Thanks
Pete

 

[Super Top]

I finally got the parts in from the states for my gearbox last week.
Brought them to my gearbox guy the next day.
Hopefully he also solves the mysterious kicking out of reverse gear under load.

 

[warbo]

Can u post up any info on your repairs in relation to reverse gear jumping out. Will be fixing mine finally around Christmas time so any info or tips will be helpful.

 

[blackvr]

^^^ I had another gearbox recently jumping out of gear, but not reverse. I cant believe the issues you 've had with you gearbox ! To try and sort this other box, which appeared all good ( like yours) in the selector dept etc, I shimmed up the detent ball , and it stayed in gear ! Give me another call when you get close to pulling it out, as I have done a few of these boxes in the last few months and noticed common things..

 

[warbo]

Do u mean shim the detent ball near the reverse gear light switch, or is it one of the other in the row of 3 detente, or something internal ?

 

[Super Top]

I still don't have my gearbox back.
But the gearbox guy said that there isn't any wear that would indicate why it jumps out of gear.
If he comes up with a solution I will post it here.

 

[White Knight]

Hi guys, any solution as yet? Just thought I would share my experience with you. First, I am not a guru with gearboxes at all, I use Tim in Brisbane for that, but I bought a box off Sean last year and he had issues with it jumping out of reverse and at tines first. Was a good price so thought fair enough. Installed the box into my hsgr and in 6 months of use it has NEVER jumped out of gear..... Weird? Or is there some silly little thing on the external of the box or new oil that rectified it? BTW, I don't drive it like its precious. Been following this thread and finally got my phone to log in.......

 

[warbo]

Probably some silly little thing like u suggest. Wish I f###$$g knew what the f######g little thing was though!! Input shaft seal is leaking = open box so will have a look end of January. If I find problem, will post pics so others reading this with the same problem don't have to go through the same stress! Have another project to get out of the way first. Grrrrrrrrrr!

 

[Super Top]

G-day guys,

I still don't have my gearbox back. It's almost ready but there is a problem with the shimming of the differential.
During the final stages of building up the gearbox, my gearbox guy found that the shims of the differential were eaten.

What you see here are parts: 5, 6, 10 and 11 on this photo.

As you can see the shims 5 and 11 are badly worn and just almost gone.
It explains why the gearbox oil was pitch black and smelled really bad.

The problem now is we can't get the shimming right.
If you put soldering wire on both sides in the places of the shims to check what width shims you need to use. The shaft doesn't centre and one wire gets pressed very hard and the other wire barely gets pressed in.

How do you gearbox experts shim the diff out?
Please help me out here.

 

[brisvr4]

Use 3 pieces evenly spaced. That should spread the load better.

 

[Rockabilly]

Torrington bearing spacer washers in my non locked center diff. Chrome hardened surfaces.
One I ground outside to clear the housing & one I ground inside to fit.

Cheers

 

[4piknup]

Assemble without washers and measure slop with a dial indicator. Add washers evenly to get your clearance. My2c

 

[Rockabilly]

Jack 3 out of 4 housings have mega cross play causing the side gears to run out of square &
the side spacer washers chew out & eat the soft housing. 2 star or 4 star still only sits
in the 2 slots. 4 washers on a 4 star will take longer to chew out with cross play.
The housing is soft & the cross is harder & the cross wins wear wise all the time. This is
my current housing that I tig welded the 4 worn spots & sanded them back to have zero play.
The 4 new surfaces won't wear out like a std Mitsu housing. The side gears run 100% square.
Centre diffs are the weakest link because the washers are shit & the housing is soft shit.

Cheers