Repairs K61M Rebuild

[95simplicity]

This is my third level of posts on my transmission. I have decided to rebuild it with a $500 kit from Tuff Torq. TT Parts and Service is only around 1.5 hrs from where I live and a nice drive thru the mountains. BTW, very knowledgeable and helpful staff.

According to TT the kit contains everything gears, seals, etc... Any tips other than the obvious "remember how it goes together"? I have the repair manual. Any additional parts I should need? Also I cannot find 5w50 syn oil around here other than Castrol. TT has oil for 8.50/l. Good oil? Or should I go with 5w40 Mobile1 or Rotella? Just because TT sells it doesn't make it the best lol.

TIA
Tony

 

[KennyV]

Hi Tony, Should be no big surprises ... Keep everything Clean as you are working.
Castrol is a synthetic according to the new definition of synthetic, as are a few others...
It's a good oil, I don't know if anyone could actually make a case for the advantage you may gain by using the Best....

There are a few other 5w 50 synthetic around... Motorcraft and RedLine both have it...
I might be tempted to use 15w 50, it's more available and is the viscosity most widely used in hydro's ... Using Any of the better synthetics is going to be fine...
Take a lot of pictures as you go at this AND post them, I'm sure others here would like to see this Rebuild... :smile:KennyV

 

[95simplicity]

Thanks KennyV. I had planned to take pictures as I go but never thought of posting them. Will do. Plan to start on the 25th as that is when I will have funds. Plus it is my birthday lol.

Yeah the Castrol is syn. I hoped to find some Mobile1 or Shell. Have used Mobile1 in all my engines (except the mower) for years. Wanted to use the "best" so wondered if anyone had used the TT oil. Since they sell it I take it that 5w50 is recommended. So u vote that Castrol is good enough? I can find 5w40 syn in many brands including Mobile and Shell. I guess I've beat this horse enough and it prolly doesn't make that much difference.

Thanks again.

 

[KennyV]

Should be Fine..
Happy Early Birthday... Hope this proves to be a fun birthday project... and do start a New Tuff Torq Transmission Rebuild thread... I'm sure it will be viewed for Years to come....

My reason for saying, about any good synthetic oil will be fine, is: ... I suspect you will change it out well before it shears down, rather than try to get the very last turn of the axles out of the oil.... :smile:KennyV

 

[95simplicity]

WARNING: THIS MAY BE A BIT WORDY :-O

Finally started the rebuild. My back gave out so had to take a break. I am working on a thread for this as I go. Anyway so far I ran into a couple of issues..

1. When I opened the case, there were a "lot" of metal shards in the bottom (top) of the case and the magnet was completely covered. HST has about 250hrs on it. I have inspected the case and gears but didn't see anything obvious. Could most of this have come from the pump, center case, etc... that I will replace with the rebuild kit? Also I plan on washing out the case and the parts that I am not replacing (not the parts in the kit) with cleaner (brake/carb/parts cleaner).

2. When I pulled the axles and ring and pinion gears, I noticed that the spider gears wouldn't turn. So like any good mechanic? I thought there might be a problem so I gave them a good twist and they freed up. It was then that I found out they were held in place with a square head bold and a couple of cupped washers. The Service Manual didn't show this, instead it showed the spider gears free spinning on a shaft. Called TT and they admitted that the Service Manual was wrong. Since the 61m is a Simp hst this is part of the Controlled Traction I suspect they never included it in the manual. My problem is that since I didn't expect this I didn't note how tight the retaining bolts were and TT had no specs on torque for the bolts. Apparently the bolts and cupped washers allow both axles to turn equally under some amount of pressure applying traction to both wheels? Sounds right to me; sort of like a locker rear end. My best guess is to hand tighten the bolts then tighten them until the square heads fit inside the slot in the ring gear. Guy at TT said sounded good to him. Can't believe there isn't a spec somewhere on this. Mine is a 98 model fgs. Controlled Traction is what sold me on Simp and I don't want to lose it but I also don't want excessive wear on the gears from over tightening. Would someone tears theirs down and let me know ;-)) I can post some pics of this if it would help.

Tony

btw kennyv I found Mobil1 Syn 5w50 locally. Even on sale for 5.00/qt at the N store. ;-))

 

[KennyV]

Pictures Always Help....
And they let us See what kind of Fun you are having...
keep at it ... :smile:KennyV

 

[95simplicity]

@KennyV. I am really glad you asked for pics since I completely zoned out on earlier post and forgot about a very important part. btw, thanks for the early bday wish and now I really feel old(er) lol. Here are the pics and an update. Any comments on quality, size, etc of pics appreciated.

Also, I am calling these spider and ring gears since those are terms I am familiar with. The Service Manual calls these Pinion gears and Final gear. Tomato, tomahto.

First pic I took during tear down, circled area is my problem. Second pic ring gear removed and the spider gear assembly. Third and fourth pics spider gear assembly taken apart (fourth closer view). And the part I forgot about in my previous post. The brass bushing that the spider gear actually rides on!! The bushing is tapered and has a type of groove machined into it. I assume that this groove along with the fluid provides a type of tightening effect as part of the CT?? The bolt and the washers actually put pressure on this bushing rather than the gear itself.

I hope, these help make this confusing situation a little clearer. Maybe as clear as mud. I really wish I had noticed all this before I gave those spider gears a twist (it would have helped if the Serv Man was correct). I hope that someone somewhere out there can help me put Humpty Dumpty back together again. I just hope I remember which side is which and which direction everything turns. Actually I'm j/k I'm sure I can figure it out with some help from some of you more familiar with a hst. My first time into one of these. I'm still gonna bug TT some more.

My local dealers were a complete waste of time. "Huh?" or "Bring 'er on down and we'll finish the rebuild for ya." or "We don't rebuild 'em, we just put newuns in"

 

[95simplicity]

After a couple of family illnesses and the fact that my back can't decide if it's gonna work anymore or not, I am finally get started on this again. Hope I made good notes on tear down. I'm just gonna put the damn thing back together and if it doesn't work right I'll just snatch it back out and try again. I did finally get from one of the dealers that there should be 30# torque at the axles. Not sure to exactly test that but will give it a try. Let you know.

 

[95simplicity]

Some advice to others. If you plan to take the plunge and rebuild your hst:

RULE1: 1st snatch out trans and disassemble. Clean parts and lcheck for damaged and worn parts before ordering rebuild kit. Also ask questions and take note of parts included in rebuild kit.

Sounds like common sense huh? Well, in my excitement and sense of urgency, I violated RULE1. After disassembly, while cleaning parts, I found other parts; some worn and some prolly damaged by metal shavings not caught by the magnet (and my failure to change oil). Now, cost of rebuild approaching cost of new trans. More that a used one if I could have found one. Haven't decided what to do. Try and return the parts I have ordered and keep looking for used hst or bite bullet and buy new one if I can find one, or order other parts and continue. :mur:

May soon have 98 Broadmoor for sale cheap (with several bullet holes and baseball bat damage, specifically on hst. It's getting so late in the season and my lawn looks like sh__ anyway (like a hay field) so I have a little time if my neighbors don't evict me. Please request no pics of lawn.

Now for some better news. Remember my prob with the spider gears and how they were mounted? I heard from Simplicity on how to set those gears. This may help others if they decide to tackle this rebuild. Validates what my dealer said and a little better/more information. Here is the response I received:

Hello,

Unfortunately, there is no specific spec for those pinion gears & bolts. What we were told was that they turn the gears, measuring the resistance & tighten the bolts until they achieved the torque value they wanted. The resistance with the gears may be the same, but the bolt torque may not be. That would account for the difference in the belleville washers.

What we do know, is what we should have once everything is done & can work it backwards from there.

When everything is assembled & the differential gear is held (parking brake on with trans assembled) there should be 20 30 ft lbs of resistance. Suggestion is to assemble things (just the differential assembly) & clamp the final drive gear, then put a torque wrench on the axle with a key & socket so you can rotate it & measure the torque you read. You might have to do it several times to achieve what it was, but if you do it that way, you値l end up with it where it was & should be.