By BrettBBonner on Unrecorded Date: Edit

My T20 in my 2000 MaxIV quit this weekend. I'm having to rebuild in the middle of hunting season. What a drag! The left side just quit.

Questions:

1. One of my T20 drums has a small grove. It is about .017 wide and about .005 deep. It apparently is from the corner of one of the plungers. This drum is from the non-input side. Should I replace this drum ?
2. What is the recommended band thickness before replacing the bands. Only the input side is damaged.

Comments:

I used Mobile 1 ATF in the transmission (supposed to be compatible with Type F) and then changed back to Type F. I'm wondering if this is what caused the bands on the input side to destruct. The right side seems fine.

And editorial complaint:

After 75 hours - I'm having to rebuild my T20 now. I'm beginning to question my purchase. Those 75 hours were pretty tough hours (duck mud), but I've kept up maintenance on this equipment.

I really wonder about the durability of this whole mess.

For instance, the GOO that is in the transmission is just incredible. I guess it is fluid and band compound. There was no metal damage that I can find. There is just no way to get the GOO out unless you tear it down. A transmission like this needs some kind of way to flush it. After looking at the transmission, I just think it looks like a continued maintenance nightmare.

By Mike Longest on Unrecorded Date: Edit

You need to call Richard Clark or RI as 75 hours
is way too short for a rebuild

Mike Longest

By Missouri's Max Dealer (Brandon_price) on Unrecorded Date: Edit

Hey Brent, sorry to hear about your T-20. I get in the same mood you are in when something breaks. You have nothing to worry about though, the T-20 is a very nice piece of equipment right along with the rest of the machine. I doubt the failure was caused by changing fluids, but I would stick with one kind. RI recommends Type F but I have used ATF for years. In my last new machine, I didn't even change the tranny fluid until at least 50 hours. The magnetic drain plug is designed to hang on to a lot of the stuff in the bottom of the tranny. I had over 300 hours on my Max when I sold it and not one minute was an easy one (as everyone should know).
I wouldn't replace the scratched drum if it is only .005" deep as that is barely anything. Just make sure it is smooth so it won't tear up the new band. How did the steering plunger scrape the drum? Does it look like the material just fell off the bad bands or was it scratched off?

By atvser on Unrecorded Date: Edit

Brett

I would use DEXTRON III with the additive.
I would also replace drum as it might just wear out new band, then you can do job again. No matter what others say

By bigredwolf on Unrecorded Date: Edit

Hey Brandon,

Sounds like a freak failure issue! Possibly an over sight of some thing during the original assembly of the T20.

My understanding is the T20 has been around a long time and has a great track record.

I do not have my maintenance manual handy, it's out in the garage right now. At what point, how many hours on the transmission, do you drain flush and refill the T20 transmission fluid? Next question, what is the best method to drain the T20 and also flush it out?

"bigredwolf"

By BrettBBonner on Unrecorded Date: Edit

Hi guys - first off, I want to thank RI and Richard Clark for their help. Both attempted to take care of me and I'm greatly appreciative. Parts will be here tomorrow and I'll get on with the rebuild.

Your questions:

1. I think it was a freak failure of the left side bands.
2. The drum was scored by the plunger. It wasn't the side where the band failure occured. I think it is just because I didn't tighten the bands on maintenance. It just didn't seem to need that.

As an aside, the tickness of the bands that didn't fail was .097". I think they were just played out . . .


I believe I will just sand-out the score and try the rebuild. Both Richard and RI said that should be OK.

By BrettBBonner on Unrecorded Date: Edit

REBUILD WRAP-UP

NOTE - If any T20 rebuilders have other suggestions, I would appreciate knowing what they did.

The rebuild was successful and I'm VERY pleased with the results. The machine operates and shifts with less effort than I remember when new. The following are some issues that one should be aware of when attempting this type of work.

BEST ADVISE - Always have the factory manuals. While they aren't great, they are better than nothing. Also use lots of vaseline to lube o-rings and hold gaskets and gears in place.

1. The removal of the master links from the chains was difficult - the final correct tool was a cold chisel and hammer. I believe there are tools for this type of work and it would be wise to have those before proceeding. I replaced with new links and I wil use these old links in a field kit.

2. Removal of the Salisbury Torque Convertor bolt from the T20 was extremely difficult. The final combination of tools was gigantic channel pliers and a long breaker bar/socket wrench. The manual suggestion for using strap wrench would not work. Nor would an 500# impact wrench work. The culprit was factory Lock-Tite and perhaps some rust. I didn't use the lock-tite on the re-assembly. However, I did use Anti-seaze on the re-assembly on shaft, key, and bolt.

3. Removal of input shaft C-Spring Clip on the input side of the T20 was extremely difficult. The final tool was vise grips and a small screwdriver to insert under the spring.

4. The final assembly was difficult and required two people on the input side assembly. The output side went pretty quick. On the input side, it was best to assemble the gear packs without the sun gear in place and then work the sun gear into position via manipulation of the input shaft et.al. The band anchor shaft didn't really want to line up in it's hole as well. I'm sure the amino acids of the first cell took about a similar effort from the almighty.

5. Put the plunger o-rings on outside the T20 and re-insert that way. Also, make sure the plungers move freely within the bores. I also used Anti-Seaze on the T20 plunger bolts. I didn't have a 9/16 socket that was thin-walled enough to fit between the bolts and the bracket without a lot if interference. I just had to make do.

By David Keeso (Argomag) on Unrecorded Date: Edit

To anyone who tries to make a simple repair and it turns out to be a huge deal.

How often do go and try to make a small change or repair to try and get your machine working better but ended up messing things up even more, or just ended up turning what should have been a short job (2-3 hours) into a long job that puts you out of a aatv for a while?

By Fred Sowerwine, Montana's Max dealer (Fred4dot) on Unrecorded Date: Edit

BrettBBonner, Couple of my thoughts. Yes, anyone working on a max should invest the few bucks to get the manuals. One broken part or about a wasted hour pays for them. Not to mention strain on the mind or skinned up knuckles.

1. For o-ring chains, use a pair of pliers to squeeze the link together a little before popping of the lock clip. I use a knife to slip in the crack on the open end and slide one side up over the link post. To put new o-ring chains on, bring the ends together with a zip lock, a pair of needle nose vise grips or some wire wrapped around the rollers a couple of times until you can get the post part in,squeeze the link together with a regular set of vise grips after putting a nut that will slip over the post (between the vise grip and the outer plate of the master link. You have to work quickly, but the o-rings will stay compressed long enough for you to get the lock clip installed.

2. You don't need to take the pulley off if you are just changing bands. I set that half on the pulley to hold it in place when I work on one.

3. I don't remember having trouble getting the clip off - you do mean the one holding the center plate on don't you. I believe I use a set of needle nose pliers open wide enough to slip over the shaft and push the clip until it slides out of the groove. be careful so it doesn't go flying across the room.

4. I'm not sure what you are referring to, But the right side (with only the output sprocket) should be blocked up with the input shaft and pulley facing straight up. Once the center bolts are taken out, lift the left half straight up off the right half and set it aside resting on the driven pulley. It goes back together the same way; right side open end up, set the left side straight down on top of the blocked up right side - might have to wiggle just a little, but the sides go right together.

5. I slide the bands in from the outside carefully and you don't have to completely disassemble the side. When I get a band in, I put the plunger bolt and head holding bracket on to keep the band from slipping too far in. Yes, the o-rings have to go on from the outside and use lots of Vaseline between and around the o-rings to help prevent plunger pop. Yes, make sure the plungers move freely (use a piece of wood to hold the plunger on when you are tapping the rolled pin in or out to prevent damage to the plunger (if there are any marks on the plunger, file them out before putting it back together). The plunger bolts should turn in and out easily by hand (if not, dress up the threads with a tap and dye. The bands should be adjusted to have 3/16" movement of the brake bar away from the case keeping the brake bars parallel with the front of the tranny case. I pull both sides of the bar out at the same time using a big screwdriver for leverage and measure right in the middle of the channel bar.

Sounds like you did just fine for your first one. I think it took me twice as long to do the first one than it should have.