A big "Thank You" to Basic88 (And a +1 Rating from me) for explaining in this other thread how to basically change out your 5 Speed Isuzu Manual Trans Fluid.

Mine needed to be done, and Basic88 explained how in this thread:
https://www.fiero.nl/forum/Forum2/HTML/117907.html

Here's the quote:

quote Originally posted by Basic88: The drain plug on an Isuzu is on the left side bottom of transaxle case just below the inner CV joint. Its 22 mm I think but 15/16 wrench worked for me. They are not meant to be super tight so usually not hard to get off unless some knuckle dragger cranked it down before you started servicing it. After reading all the horror stories about the "little gear falling off" I fill mine through the top hole left side of tranny case.After removing the plug.. there is a little spring in there, I take it out....make a tight fitting funnel out of the pennzoil syncromesh fluid bottle with the bottom cut out....and I add 2 quarts of fluid....no runs...no drips...no errors....no little gears to fall off anywhere. Thats my experience yours may be different.

Now, I realize a lot of people out there might still have questions so I will include pictures here to help anyone who may be afraid of removing the wrong bolt or screwing something up.
For this job you will need:
Ramps/Jack and Jackstands (safety first!)
22mm Socket, 17mm socket, Breaker bar and ratchet
2 Quarts Pennzoil (or other suitable) SYNCHROMESH manual trans fluid. I got mine for 6.99 +tax from advanced auto.
Drain pan
Gloves and a rag for keeping your hands clean if you so desire

Get your back end up in the air and safely secure it. I used ramps and wheel chocks to prevent my car from rolling while I was underneath.
Next, place your drip pan under the transaxle just like you would if you were doing an oil change.
You are looking for this big 22mm bolt on the driver's side of the transaxle case, just forward and above of your short shaft.
Break it loose, unscrew it and be ready for the fluid to come out just like if you were changing your oil.



Once all the fluid comes out, replace the bolt and tighten down.
As Basic88 said, you can use a 15/16 socket in a pinch and you don't have a 22mm.

Next, get under your decklid and remove the 17mm bolt sitting out in the middle there toward the top.
Its near your slave cylinder somewhat. When you take the bolt off you will see this spring.


Remove it with your fingers so you have a clear open hole to pour your fluid in.


Here's the bolt and spring outside of the hole.. I set them like this so I knew which end went back into the transaxle case.


Since my fluid looked like chocolate milk, its a good thing I got two fresh quarts of synchromesh.


The tip of the fluid bottle has a cutoff spout, I cut it off small. Just put the tip in the open bolt hole and squeeze the fluid in.
Two quarts takes a little time, so you do not overflow the fluid. Get every drop in there.

Finally, replace the spring and bolt and tighten down. You are done. I hope this basic tutorial helps someone who may need the visual to know what to do.
If you think of this as nothing more difficult than an oil change, it should not scare you and should be a piece of cake.

tbone42

Thanks, gonna do mine in the morning.

Hey, if I've been using 5W30 until now, is there a flush involved, or are they compatible? I'd like to switch to synchromesh.

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tucsonsean

Good thread! I never knew about the bolt 'n' spring. I always filled through the VSS hole.

Sean...
Just drain the 5W30 and pour in the synchromesh. They're both just "oil".

Not sure if it's any easier, but here's how you can fill it up through the VSS hole:



Once the VSS is pulled out, slip a funnel into the hole and pour from up top:

quote Originally posted by Bloozberry: Once the VSS is pulled out, slip a funnel into the hole and pour from up top: [/IMG]

How is the VSS held in?

quote Originally posted by 2.5: How is the VSS held in?

IIRC, a 10mm bolt holds a small flat plate that fits into a slot on the VSS.

Exactly. Here's a pic... the only difference is that I've replaced the hex head bolt for an allen head bolt:



And here's a (busted up) VSS once removed... it's also missing the plastic gear that's supposed to be on the end of the shaft. Notice the two lines on the snout for the correct oil level:

[This message has been edited by Bloozberry (edited 04-23-2012).]

I hate using the VSS for the fill. One time I was very close to loosing the plastic gear inside the transmission. Scared the crap out of me. At least my dad's Isuzu has a dipstick.

Just a little tip for any gearbox oil change. Loosen the fill bolt first in case something bad happens with it you will still have the trans full of fluid. This application isnt as critical because there is more than 1 way to get fluid in it.

quote Originally posted by tucsonsean: Hey, if I've been using 5W30 until now, is there a flush involved, or are they compatible? I'd like to switch to synchromesh.

The synchromesh looks an awful lot like motor oil. I cannot give you a "definite" on the flush question, but I am betting if you warm that fluid up by driving it for a little while, and then drain it until there are no drip, you would be clear to switch in the synchromesh.

As far as the VSS goes, I avoided removing it because I heard all the nightmare stories about people dropping the little gear off and not being able to retrieve it. The only benefit I see to using the VSS hole is that it is also your trans fluid dipstick. (As shown in Blooz's picture..) You really don't need it, though, because the max line is just a little over 2 quarts, so 2 quarts ought to do it every time. Someone correct me if I am wrong, don't want any noobs destroying their clutch and blaming me.

I have been driving a bit on it, and it is working great, feels smooth.

Edit: For reference, I took the VSS out to show what the gear looks like and the hole with fluid down in there. The gear BARELY fits through that hole, so I recommend after breaking the hold down plate loose, carefully back and forth lift until you feel it give then slowly lift it out. I had no problem with the gear falling off, but I bet it would have if I just yanked it out of there in true "knuckle dragger" style.




From all accounts I have seen, you will want to change this at 50-60k miles. My car has 58k, so I figured after 26 years it was time to do it. Should be good until the year 2037 now... because I doubt I will hit 120k miles. Ever. My truck gets all the heavy driving, this is and always will be my "toy".

[This message has been edited by tbone42 (edited 04-26-2012).]