how do you add fluid to an isuzu 5-speed transmission? What type of fluid do you use? How do you know how much is enough? When i changed cv shafts, i pretty much lost all of my transmission fluid.

Sorry if it has been covered before, i searched and didnt find anything.

To fill the tranny, you have two choices: There is a hex plug on the driver's side of differential case that can be used for fill up. You simply fill the case until it's level with the bottom of the hole when the plug is out. I've found that not all Isuzu's have a removable plug though. The transmission in the photo below shows you one that has a round headed plug rather than a hex headed plug so it isn't easily removed (nevermind that this Isuzu is on a V6 car). You also need a big syringe-style oil gun with a hose on it to reach the hole.



I find the second method easier, which is to fill the transmission from where the VSS plugs in. You can do it without having to raise the car. Simply remove the 10mm hex bolt that holds the VSS hold-down bracket and pull up on the VSS carefully so as not to pop the gear off the end of it.



Set yourself up with a funnel in the hole and pour 2.5L or 5.3 pints of either 5W30 or GM's Syncromesh transmission fluid. Engine oil was the original fluid used in these transmissions however the Syncromesh came out later as an upgrade.



If you want to double check the level is correct, then you can use the VSS as a dipstick. It has markings on the shaft like the one below (the gear is not on this one).

[This message has been edited by Bloozberry (edited 10-16-2011).]

Isn't there a gear on the vss shaft? Have to be careful it does not fall of when removing the vss otherwise you are going fishing!

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Dave

www.ltlfrari.com

The best method is to use the VSS hole. Even if the gear falls off, it can't slide past the differential into the case, so fishing it out of the hole isn't that big of a deal.

Isuzi was kind enough to give those of us with the '90+ transmission a proper fill hole and dipstick:

Is there a transmission fluid drain plug on the Isuzau 5-speed tranny?

Yes there is. I don't have a picture of where it is, but it's located close to the seam of the two case halves, on the underside of differential portion of the housing. The plug is a hex bolt that's facing downward... can't miss it.

Although not an Isuzu, here's a Getrag as an example to show you where to look:

Bloozberry mentioned the GM Syncromesh fluid. Many report much smoother operation after converting from oil to the Syncromesh. Rather than pay the $20-25 per quart at a GM dealer, you can get Pennzoil Manual Transmission Fluid at AutoZone. It's made by the same folks that make the GM product. Costs about half as much, too.

Ill try and snap a pic of my drain plug on my Isuzu ...

I just topped my tranny off with some 5w30 might do a flush and try syncromesh

Pennzoil also makes syncromesh and it it labeled as such. Yes it makes a big difference in shift smoothness, especially in cooler temps. Got mine at Autozone.

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Jonathan
23K mile '85 notchie w/ 88 cradle, '87 2.8/Getrag, Air, PW, PDL, PM - Still under construction
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