Transmission q?`

[denverdandb]

This is my first post, im fairly new here, have a substantial knowledge base, but i still have a few questions.

First off: I have a 91 GSX with a few mods, JDM block, Big 16g, FMIC, Apex-i AFC II, 3" turbo back, Blitz Dual SBC and some intake mods like a 2nd gen ported MAF.

Ive been having problems with my transmission lately, so instead of having it rebuilt i bought a remanufactured one. The good people at arapahoe mitsubishi are doing the work. When they installed the trans nothing went wrong, the box went in just fine. Now that they have the gear box in, and everything bolted back up they are having problems.'

The first one is that it only shifts smoothly when the car is NOT running. when the car is running they can't get the gears to disengage from the clutch. Do i need a new master or slave cylinder? I cant figure it out, and they have had my car for nearly a week now. The master/slave cylinder is all i could think of.
Any ideas? Thanks
-Paul

[Hal]

Master/Slave, broken p/p plate, broken disc, trans/engine bolts not tight, or simply out of adjustment.

[v413nc3]

A couple of things. How do you port a MAF? Second why the JDM engine?

The shifting issue is clutch adjustment. Have them properly adjust the clutch (it's not fully disengaging) and you will be fine.

*edit* Damnit Hal beat me to it :)

[denverdandb]

You'll have to ask the first owner about the MAF, The JDM block is in there because it has forged parts, not crappy stamped parts from d-troit.

[v413nc3]

If you wanted forged parts why not just use good forged pieces. And those "crappy" parts have gone well over 600hp. JDM engines usually are a waste of time since the USDM 6 bolt is identical and cheaper. The only time I can think of to want a JDM engine would be the E3 7 bolt.

The MAF is probably hacked instead of ported. And normally this leads to pretty major issues. 2G MAF's don't take well to having their honeycombs removed.

[denverdandb]

Like I said, talk to the previous owner, the car was built and maintained by MAC autosport. Personally i bought it because i wanted a project car. Besides, why buy and install forged parts at extra cost, when you can have them in the block in the first place. The motor is far stronger than anything i want to do with it, It already made 277.9whp and 312 tq at 18 psi, its good for some more but why push it, im happy for now.

[v413nc3]

I don't think I have seen anything specific about JDM engines having forged internals. Not to say they don't have them but I do not recall anywhere that confirmed it. *shrug* As to why, probably because I've seen mitsubishi and how they "forge" their pistons. Such as all the E8 pistons cracking. I'll take my crower/ross combo and be happy, but to each his own.

My advice on the clutch would be to put the car in gear, then start it with the clutch depressed all the way. If it moves forward while cranking then you need to adjust the clutch rode out (into the firewall) more. Get to the point where it fully disengages but try not to go too much past that or it won't fully engage. That should solve your issue unless something is actually broken.

[Mirage]

The "JDM" 6-bolt engines are the exact engine in the US DSM's minus the cyclone intake manifold and a few '90 USDM style sensors.

I've had several JDM engines apart and they have the same markings everywhere as your typical 6-bolt.

A stock USDM 6-bolt has been proven up to around 550 whp before breaking anything (or in my case, about 450 whp before a crank snaps. Long story).

I just hope they didn't sell you on the JDM engine because of the forged internals they advertise they have. Because they don't. Not in the typical sense at least. JDM as Hal put it some time back "is just from a japanese junkyard" Or something to that effect.

Clutch issue. My guess will be worn pedal assembly, leaking/unbled master/slave or dislodged springs in the clutch disk. All will cause what you're describing.

Marcus

[fusionsport]

First- what clutch are you using? If it is an aftermarket high-clamping force unit, then you will likely need to shim the throwout bearing arm pivot with a couple of washers to give it the leverage needed to make the clutch work better.

1G's have an issue with the pedal housing, especially with uprated clutches. Seems to go something like this: Everything works fine on the existing clutch, with maybe a little issue once getting into gear once and awhile, will feel like a "stiff" gearbox or too heavy a fluid. When the clutch is replaced, especially with an uprated unit, you have trouble with the clutch disengaging- in my particular case, the clutch would not release at all. You can observe the pedal rotating on its mounting pin in an elliptical fashion, allowing the pedal to move quite far in its travel before it actually moves the clutch master cylinder pushrod. In effect, you simply run out of travel. The only cure for this is to either replace the pedal assembly(strongly recommend) or pull the pedal assembly and have a heavy washer or similar welded on to repair the worn out hole. I had to do this on my red 90, and it was a PITA, and by the time I was done Jack and I could pull the pedal assembly in under 20 minutes.

[denverdandb]

Yes, the car has an upgraded clutch, a 2600lb street disk if i remember correctly. But the same clutch was in my previous transmission, and never caused any problems. Arapahoe Mitsubishi called today and said they think the clutch may have popped a spring when they put it in, so theyre taking it all apart again, if they still have the same problem ill tell them about the washers in the pedal assembly. Like i said, ive never had a problem with this clutch before as it has been installed with this car in the past. The clutch is a centerforce dual friction 2600. Thanks again for your time guys.

[denverdandb]

Turns out it was a throwout bearing in the trans, arapahoe mitsubishi broke it so they are going to replace it. Thanks everybody for all your pointers and help on this subject.

[buckley]

Glad they figured it out for ya. Good luck getting the car back together...


buckley

[hollywood]

In response to the earlier recomendation of adjusting the clutch.>>>

I would assume that an improper adjusted clutch may also cause the occaasional buzz or hard shift between gears, (another possibility is bad syncros) but I'm trying to diagnose any possible sysmptoms before pulling trans.

Question >>> ?

What would the proper adjustment procedure be?

Would you recomend following a Chilton's manual, or are there any tricks to it?

CAR >>> 1990 GSX,

Also would a NA trans from a 1990 *Galant* GSX be a direct swap into this car?

Thank you for any replies!!!

Peace
Ryan

[fusionsport]

IIRC the GSX has different gearing in the front diffe and t-case making it nec. to change the gearbox,t-case, and rear diff all at the same time.

[hollywood]

I would be getting the whole car.

What is the gearing difference, which is higher/lower, and would that bolt to my 6 bolt motor. I would assume it would, same year. Is there any major obstacles?

[fusionsport]

it will all bolt up, no idea on the gearing. If the car isnt destroyed your better off selling it to someone who wants to make it into a VR4 clone and buying a decent transmission.

[hollywood]

I will buy a whole car if nessasary for spare parts, or any old trans, I will rebuild myself regardless.

Any leads on good boxes? ;)