T-20 dissassembly

[ericood]

Well I have dug into the rebuild of our Attex and I am having trouble disassembling the transmission. I printed pages off 6x6 and I have removed all the split line bolts and the case halfs only come apart about 1/8-1/4 inch. What's the trick? Also has anyone installed an Onan engine in a Attex? I am going to try but it looks like a very tight fit.

[racerone3]

Well I have dug into the rebuild of our Attex and I am having trouble disassembling the transmission. I printed pages off 6x6 and I have removed all the split line bolts and the case halfs only come apart about 1/8-1/4 inch. What's the trick? Also has anyone installed an Onan engine in a Attex? I am going to try but it looks like a very tight fit.

look to make sure both diamond shifters are in neutral. you could also take the bolts out of the plungers and push the plungers into the trany a little bit. this would take any tansion off the bands/ drums incase they have any kind of side load on the main shaft. no clue on the Onan, but Hydromike has wedged some interesting engines into attexs, look up his gallery. might at least give you some ideas.

[hydromike]

Hey Ericood,

Race is right. Put the shifters in neutral as a start, and take all the tension off of the bands by pushing the plungers in a bit. Unless you plan on replacing the O-rings on the plungers, be careful how far you push them in, because once the O-ring goes past the end of the plunger bore and into the case, there's a 99% chance you'll tear it if you try to pull it back out. The starboard side of the T-20 case will pull off if you have all the bolts out, and shimmy the shifters a bit while trying to pull them apart. Don't force it, since it's just a nice, easy slip fit. It just has to be lined up right to come apart and go back together.

A flat Onan twin should fit in there just fine. There's a lot more room in the machines than most people realize. It's all a matter of planning the fit, and rerouting some things as necessary.



~m

[Don]

Your center plate may still be stuck to the right case half. Make sure it's loose from that side before you try too hard to split the cases. The center plate has to stay with the drive side (side the clutch goes on) until the clip is removed from the end of the input shaft.

HMike's right about the Onan- somewhere I've seen a pic of one mounted in the back of an Attex.

[racerone3]

good call on the o-rings H-mike... i was just assuming they would be replaced, but i hear bad things can happen when one assumes

[tattooman]

Hi, I put an Onan 18hp in an Anphicat. Had to raise it up four inches. Had to get a longer belt. Works very good. I have posted pictures of the way I did it on this site. You might want to check it out. Good luck, have fun!

[ericood]

Thanks for the input. I tried with the shifters in all locations but I did not jiggle them when I was trying to split the cases. I did push in the plungers to no avail. That is part of the reason I'm taking it apart is to inspect everything and change "o" rings and so on. Don you said something about the center plate being stuck, what's the trick there? Also can anyone tell me where to get a good print of the tranny. Everyone I found when I print them out are very hard to read. I'm willing to buy it.

[Don]

If the center plate is stuck into the right case half, you'll find they only come apart a short distance like you described. If that's the case, you don't want to pry them apart or you can distort the bands and run into more trouble. You can usually use a small pin punch and catch enough or the plate through the bolt holes (go through right case half bolt hole at an angle enough to catch the steel center plate and knock it loose). I have one apart now and I'll post some pics tonight if I can.

[ericood]

Thanks Don I'll look to day but I don't think it's far eenough apart to use a punch yet. At least I know what I'm dealing with. Pictures would be great

[Don]

You don't need to have the cases split far for the punch. You can usually get enough of a bite on the center plate putting the punch through the hole in the case to knock it loose. Before the transmission goes back together, check the holes and make sure you didn't burr the hole or the edge around it. A file with put it back in shape if needed.

[ericood]

Don I tried what your showing in the picture but the punch is only hitting the other case. I'm not sure what I'm trying to do here, Am I just knocking something loose? You call it the plate and the very poor diagram I have is not clear enough for me to understand the assembly and it does not refer to a plate at all. I'll look in the morning to see if you can shed any more light on this. Thanks

[Mike]

You can see the plate in the T20 how-to rebuild article: http://www.6x6world.com/forums/aatv-...r-rebuild.html The eighth picture down after "Let's Begin" shows the plate. Then scroll down to the "Left Side Disassembly" section and the first 4 pictures also show the plate.

[ericood]

Don the punch only hits the case on the other side. I'm I just trying to knock this plate loose? I do not have any pictures that show how the transmission is put together , very poor copies. In the pictures I have they do not refer to a plate. I'm a bit perplexed at this point. I think I will hang the gearbox from the mounting bolts and try tapping on things to free it up.

[ericood]

Sorry I posted the same question/answer I didn't see page 2. Mike thanks for the link now I see where I'm confused. Where is the post of the transmission rebuild? I have looked on over and over and never found that.

[duckhunt81]

I had this problem before, when the PO had put silicone to seal the case halfs. If you look all around the center holes you should be able to find one that the holes on the case half and the holes on the mid plate are off center enough to get a puch on. (you are tring to hit on the steel mid plate) It will take a few hits to knock it loose.