Quadratrac Questions about my rebuild

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Triumph215
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Quadratrac Questions about my rebuild

Post by Triumph215 »

I have the 'original' Quadratrac that came with the truck when I bought it 4 months ago, supposed to be 1977, it has the Mile Marker 2x4 OD kit in it. The story goes the chain was slipping and they found a deal on an existing one so they swapped it out. I was going to do nothing but the existing one is leaking now out the front seal. At least I have a spare.
Bought the BJ's rebuild kit with chain. This is the first time I've been inside one of these and I replaced all the seals and got the chain on, it's all back together but I have some questions.
-One of the planetary gears is tight, not terrible but not free. The opposite gear is so free there's about a .030 gap and I can click it up and down. The other two seem normal. Should I be concerned about this?
-So looking at it on the bench from the back without the low range attached and turning the driveshaft yoke clockwise, the gear the planetary set attaches to, climbs out of the case towards me. If I turn the yoke in the opposite direction it sucks the gear in .067" and I can see that the back of planetary gear assembly has been rubbing on the transfer case enough to score it up. Putting the snap ring on reduces the play but when turning clockwise it still draws it in hard enough to drag on the case noticeably. Which way does the driveshaft turn in drive? Is this a problem only in reverse?
-When locked into 4wd there's about 35 degrees worth of play in the driveline between the front and rear driveshafts. So if I hold the rear driveshaft yolk I can clunk the front one back and forth about 35 dregrees. This seems like too much.
I don't have any parts left over :D but unfortunately I didn't check any of this stuff before I took it apart.
I'm just trying to be sure I have it together properly before I go through all the effort to put it in.
1964 Triumph TR4 with 1964 Olds 215 heart transplant
1977 Wagoneer
2009 BMW GS1200
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fulsizjeep
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Re: Quadratrac Questions about my rebuild

Post by fulsizjeep »

Triumph215 wrote: Sat Apr 10, 2021 8:24 pm -One of the planetary gears is tight, not terrible but not free. The opposite gear is so free there's about a .030 gap and I can click it up and down. The other two seem normal. Should I be concerned about this?
Yes. These gears should spin freely. It's possible the pin that goes through the gear is bent a little bit.
Triumph215 wrote: Sat Apr 10, 2021 8:24 pm -So looking at it on the bench from the back without the low range attached and turning the driveshaft yoke clockwise, the gear the planetary set attaches to, climbs out of the case towards me. If I turn the yoke in the opposite direction it sucks the gear in .067" and I can see that the back of planetary gear assembly has been rubbing on the transfer case enough to score it up. Putting the snap ring on reduces the play but when turning clockwise it still draws it in hard enough to drag on the case noticeably. Which way does the driveshaft turn in drive? Is this a problem only in reverse?
Not answering the last 2 questions. There is a problem here though. The sprocket should not rub the case.

Image

In the diagram above, locate the "Plastic Thrust Washer" to the left of the Drive Sprocket. If this is not installed, the drive sprocket will grind away at the case. Does yours have that? A better look below. It is in top of pic.

Image
Triumph215 wrote: Sat Apr 10, 2021 8:24 pm -When locked into 4wd there's about 35 degrees worth of play in the driveline between the front and rear driveshafts. So if I hold the rear driveshaft yolk I can clunk the front one back and forth about 35 dregrees. This seems like too much.
This is normal. The design helps prevent the tcase from binding up in 4wd and also make it a little easier to shift in and out of 4wd. This is not a shift on the fly setup. You should be stopped to shift in order to prevent damage to the slider/shift collar.

There is a bunch of QT info in a link in my signature including TSM and MileMarker part time kit installation manual.

If the images do not show, my web site is doing weird poopoo this morning.
Flint Boardman
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s
https://jubileejeeps.org/quadratrac

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

Yes it's the drive sprocket that's moving. The thrust washer is there and seemed to be in good shape, so I reused it. I should have measured the thickness but would guess it to be about .100". The washer is made of a heavy seemingly papery material but seemed very strong and is uniformly thick, it's installed correctly on the notch. I tried to move the gear assembly in and out by hand and cannot. (If) I have the parts installed correctly it makes me wonder about the case not being 100% square or the needle bearing set being overly worn but visually the needles all seemed fine, move freely and aren't pitted.
About the sun gear, should I look for a replacement assembly? The other gears associated with it seem to all be in fine shape.
And thank you for helping me, I was hoping you would see my post.
I hate the though of taking it apart again but not as much as the thought of it failing in the truck miles off the main road.
1964 Triumph TR4 with 1964 Olds 215 heart transplant
1977 Wagoneer
2009 BMW GS1200
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Re: Quadratrac Questions about my rebuild

Post by fulsizjeep »

You're welcome. Edited 11:01 MST

On the pinion cage... The gear tooth surfaces wear on each other much like the ring and pinion in an axle. So I consider the pinion cage, sun gear and ring gear all a matched set. I would never mixed used ones but get a set that have been used together instead. Others may disagree but they have a right to be wrong. I lied. I have replaced just the sun gear before because the 10 spline for the shaft was bad. Didn't have much choice. It's not exactly easy to find this set that is in good shape.

Which case half is getting ground on at or by the drive sprocket? Front or Back?

Did you find a lot of metal flake in the fluid you drained out? If yes, is it aluminum or steel? A magnet will tell you. I imagine that fluid is long gone now.
Flint Boardman
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s
https://jubileejeeps.org/quadratrac

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

It's the outside rear that's taking the abuse from the drive gear, the side inside the low range assembly. The case was drained when I got it so I don't know about metal in the fluid. There was plenty of grey in what fluid was left inside but not terrible. To me it looked more like aluminum residue than steel, almost powdery fine.
Which way does the drive shaft turn in drive? If clockwise looking from the rear then I'm hoping to be ok because the problem is in the anti clockwise direction.
I can pull the low range off the one in the truck and use it in this one (maybe?) but that still doesn't save my gear movement issue.
The QT in the truck looks different externally than the one on the bench, I'm hoping all the internals will be the same.
1964 Triumph TR4 with 1964 Olds 215 heart transplant
1977 Wagoneer
2009 BMW GS1200

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

And I've done a lot of reading on your website, it's been super helpful and helped me not worry about taking it apart.
1964 Triumph TR4 with 1964 Olds 215 heart transplant
1977 Wagoneer
2009 BMW GS1200
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Re: Quadratrac Questions about my rebuild

Post by fulsizjeep »

If the truck QT looks different, are you sure there is a low range?

Low Range
Image

Without Low Range
Image

I would not run it with that grinding. I'm still confused... Is it grinding where the orange arrows point?
Image

Maybe that Low Range is just jacked up. I should have already said, the best bet is to replace the low range with one that is working right.
Flint Boardman
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s
https://jubileejeeps.org/quadratrac

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

Fortunately there's a low range on both TC's so I have a potential replacement there and yes it's rubbing exactly where your orange arrows point. Actually, looking at your picture, I think there's more material missing than I'd originally thought. It's still on the bench, I'll take the low range stuff off and look. I only put the low range parts back on to keep the case from being open to the air as it's so humid here.
1964 Triumph TR4 with 1964 Olds 215 heart transplant
1977 Wagoneer
2009 BMW GS1200

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

I misspoke, the notch is plenty there, the back of the basket is scored too.
I’ve been wrestling with Tapatalk for an hour so I can show you but I can’t get it to work.
I’ll keep trying.
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1977 Wagoneer
2009 BMW GS1200
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Re: Quadratrac Questions about my rebuild

Post by fulsizjeep »

So, it's sounds like the big C-clip is not there to hold the pinion basket in the correct place on the drive sprocket. But you say you have a snap ring so I wonder if it did not have one for a while to set the ball rolling on wear.
Flint Boardman
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s
https://jubileejeeps.org/quadratrac

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

Any chance you have a capable Quadratrac person you could recommend in California? I've pored over the drawings and I can't see where I'm missing any parts internally. I can replace the Low Range with the unit in the truck currently but that doesn't resolve my gear walking problem and I can see by your photos it shouldn't be rubbing. I could futz with it myself but am super busy with work and the damn things are heavy as crap, I'm going to bust a nut wrestling with them if I keep it up.
Interestingly, I can't find a picture of the snap ring/C-clip that holds the Pinion Cage on (If that's the correct term) in either the drawing you posted here or on my 2 by 4 conversion exploded diagram. It's basically a ring with the ends curved up and away from the circle. It's pretty easy to get a little screwdriver under it and pop it off. The snap ring is .063" thick.
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1978J10REDWHITE
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Re: Quadratrac Questions about my rebuild

Post by 1978J10REDWHITE »

I actually have one with hi/lo completely torn apart. If I am able can maybe give you a spec or measure one point to see If what i have is different then your part spec reads, thus maybe prove or help know if excess wear exists.

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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

Hi J10 RedWhite, thanks so much. I'll need to split my case again to compare notes with you.
In staring at it in annoyance I turned the assembly to walk the gear out all the way and found I can push it back in by hand. This to me means there's too much room inside the case because I'm not missing any spacers that I know of. Could it be the bearings weren't placed correctly? I didn't replace them.
Along with my truck I have the original 2 by 4 paperwork including assembly instructions. There's an addendum with the instructions about the shift fork on a separate sheet of paper telling of a variance in cases of up to 0.100" and how to modify the fork but it makes me wonder if that's what's going on here.
Here's the wording of the Addendum.
- "For some reason unknown to us,(and it would appear also unknown to Borg-Warner) it is possible for the 1339 transfer case to have a variance of 0.100" in the internal stack up dimensions. This has the effect of not allowing the slider to penetrate deep enough into the coupler." It goes on the say it'll pop out of 4wd under a load blah blah.
My question here is I don't know exactly what to consider the Internal Stack Up dimensions? For sure there's slop inside on the drive gear side and I wonder about having a shim made out of brass or something.
I'm considering looking for a cover plate to buy and leave the Low Range off for now to give me some time to take the other one apart.
Anyone have an extra cover plate I could buy?
1964 Triumph TR4 with 1964 Olds 215 heart transplant
1977 Wagoneer
2009 BMW GS1200
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Re: Quadratrac Questions about my rebuild

Post by 1978J10REDWHITE »

You might los around cll for a used TC and hopefully can locate something. Might need to buy th entire thing as ppl would probably ant to sell the entire unit and out pat out .
I recall a little about the 0.100” offset thing yet cannot recall much about it or even how to assess what I actually have too.
Recently got the 2X4 from BJ’s finally after waiting 5+ Months for it so am going to have to Learn about the offsets actually and consider my scenario , look into this also If I put it in.
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Re: Quadratrac Questions about my rebuild

Post by fulsizjeep »

The low range "delete" is more than just the plate. You also need 2 parts that connect the tranny tail shaft to the drive sprocket.

Image

I have a spare and it is packed in the Jeep when going out for off road fun. Kind of handy in case the low range unit gets jacked up.
Flint Boardman
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s
https://jubileejeeps.org/quadratrac

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

That's a brilliant idea I'd have never though of. Thanks for the heads up on the other parts under the cover, I saw them but they were referred to as PTO parts so I assumed I wouldn't need them. I'll start hunting around for parts.
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Re: Quadratrac Questions about my rebuild

Post by fulsizjeep »

I was moving some of my junk around yesterday and found a low range unit that has wear on bottom side of pinion cage from rubbing against the aluminum case similar to what you describe. I am betting your pinion cage looks similar. Also notice the 10 spline on the sun gear. It is pretty beat up. This wear is what creates a clunk noise when going from N to D or R. The more wear, the more clunk.

Image

That surface should be flat and smooth.

Image

The C clip is a little worn as well. You mentioned what yours looks like. Does is appear to match this one?

Image
Flint Boardman
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s
https://jubileejeeps.org/quadratrac

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Triumph215
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Re: Quadratrac Questions about my rebuild

Post by Triumph215 »

Yes ! That’s exactly what it looks like, the snap ring too. But now that I know, how do I figure out where the problem is? A kind forum member is gifting me an old QT but once it’s taken apart in front of me it’s going to be interesting to see if I can figure out why the existing drive gear walks up and back.
My initial thought is to put the empty case halves together and measure the depth of the cavity but past that I don’t know.
1964 Triumph TR4 with 1964 Olds 215 heart transplant
1977 Wagoneer
2009 BMW GS1200

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Re: Quadratrac Questions about my rebuild

Post by Pair O J10 »

It would be my opinion you are looking for a problem that doesn't exist. The drive sprocket floats between the case front half and the rear thrust washer, the fact your pinion carrier is showing wear my be indicative of hard use, low lubrication and age. You will note that the engineers placed the thrust washer at the rear of the case because this is where thrust loading occurs, in other words in normal operation the drive sprocket moves toward the rear of the case. The design of the QTRAC never allowed for any type of compensation for wear in this area. If the thrust washer is in place which for all practical purposes positions the drive sprocket further forward in the case which would make your perceived problem worse by moving the pinion carrier closer to the rear face of the case there is nothing else to consider. Replace your pinion carrier if you feel the wear on its face is detrimental to long term serviceability of your case or return it to service as is...You will note that all of the pinion carriers show wear in this area yours is just worse than most. As I said, I just believe you are chasing a fix for a problem that doesn't exist.

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Re: Quadratrac Questions about my rebuild

Post by SJTD »

Hard to believe there's no provision for thrust in the opposite direction. What happens when you're in reverse? In a high load situation?
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