904 Transmission quality

Guys,

I found a good deal on a "new" JVX Racing Fully Build Transmission, it has full manual valve body, transbrake and capble of handling @ 700 hp.

The " downsite " of it is that has been sitting and stored for about 15 years....

All the internals are brand new as this transmission was build and never used. It has been store with the required plugs to avoid dust entering the transmission. The transmission was stored without any transmission fluid.

What do guys think about this..... Do you think the internals are still in good shape??

Yes ,I put a 904 into service(fresh build). It sat for 10 years. It was a backup built for my drag car and was never needed.Don't know the conditions yours was stored. As long as it was dry and inside.In a humid enviroment it may have developed rust on exposed metal.

I would be concerned about the wear items like seals, etc.

Pull it apart and go through everything, they are pretty simple transmissions.

If you're not going to do that, at pressure check it on the bench with a plate to make sure everything is working as it should.

put a new front seal in and run the bag off it .

rmchrgr said:

I would be concerned about the wear items like seals, etc.

Pull it apart and go through everything, they are pretty simple transmissions.

If you're not going to do that, at pressure check it on the bench with a plate to make sure everything is working as it should.

Click to expand...

Can you pls discribe this process of plate of? I Am sorry... I am not a transmission specialist.. I am going my way up on this.. tnx

Jax said:

Can you pls discribe this process of plate of? I Am sorry... I am not a transmission specialist.. I am going my way up on this.. tnx

Click to expand...

Call JVX and see what they say about it. They'd probably steer you in the right direction.

It's a sealing plate that lays over the valve body with the pan off. It has orifices in certain spots to put compressed air into the valve body passageways. It basically emulates what fluid does to actuate/hold the gear train and servos but it's dry. Basically it's a back door way to test seals without taking the whole thing apart to check them. You can hear the parts working inside, and if the seals were no good then stuff would not operate correctly when pressure is applied. It's just a quick test and does not tell the whole story but it will give you a fair idea of what's going on inside without dis assembly. But, if you found one point where things did not seem right then you'd be tearing it apart anyway. You might need a chart to know what the gear train was supposed to be doing in each gear. A trans shop could probably do it for you pretty easily but they'd probably have to dig out their old checking fixtures. See pic below.



If it were me and I was spending some coin on a used unit, I'd wanna be sure it worked as advertised.

I'd pull it apart and check it over. Last year I bought a trans from a fellow that was rebuilt 10 yrs. prior and stored. I pulled it apart to check it and the front pump had rust in it. Looks like they cleaned it super good, slapped some assy lube on the gears and put it together. Naturally the cast iron pump rusted after sitting so long. It's nearly impossible to completely bag them so absolutely no moisture gets in. You can slow it a lot but stopping moisture is hard to do. Where your located affects things too. I'm in the Midwest, aka humidity central. If your in AZ or another very low humidity area things are much better.

Wish a Trans like that was for sale near me

Thanks Guys... I think I will work it out with the owner....