MTFCA Forum

I need pictures of your rear axles in disassembly. I need pictures of 17-27 components of the TT rear axle Any picture you've got of these parts is greatly appreciated, primarily I'm trying to figure out how the pinions are held within the ring gear. The worm is pretty straight forward, got that. I have found that there is a fiber thrust washer on the axle...does that go between the axle shafts like on the cars or somewhere else?

Anyhoo, any photo's you've got will be greatly appreciated, thanks.

I don't have any photos if it disassembled, but maybe this will help:

I have these too, in fact I colored one of the Cross Sections already...but what these don't show is what the parts actually look like...these are not Ford assembly drawings, meaning they were never used to assemble the TT rear axle, they are book illustrations intended to explain what the parts are, but rarely show how they actually look.

I need to see the actual parts that hold the pinions in place. I know that the differential covers goes over them to hold them in whatever plate is between the two covers. Then there is a bearing that mounts onto the ends of these covers, that fits into the rear axle housing. If somebody has an original copy of the Ford Assembly drawing that was used by the Ford Motor company to assemble this rear axle, I'd love to see it, but what I really need is those parts that retain and hold the pinion gears inside the ring gear.

here are some

More photos. We are in the process of making felts that fit were they should. What I have found is either the hole the driveshaft coupler or axle fits through is too small or the outside is too big. The outer cup and felt is the bearing retainer.

Hi Martyn, hope these are helpful. This a Ruckstell internals.
Cheers
Adrian

Reassembled Diff:

Brake shoe details (yes, these are broken.. one side of pin brackets broken off .. but shows the design )

Brass housing from Ruckstell

Please send me a PM as I have a range of 'spares' and can photograph with a ruler for dimensions of parts if that is a help.
Cheers, Adrian

This is "before" disassembly - ugh, took a bit to get that sludge off!
I forgot to photograph the nice clean reassembled internals....
The 'cage' has its boss broken - which is seen to the right on the axle a bit. The "real" problem was the two worm Hyatts which were rusted solid which explained the reason this diff did not turn.

The Ruckstell stuff is terribly interesting, since I didn't know anything about one for the TT. And of course I'll do it too, but for right now, I'm working on the standard TT rear axle and the pictures that were posted of the worm and its bearings are some I've not seen before. If you've got more, please post them, especially ones of the differential gears.

Thanks again for these great pictures, they help a lot.

Martynn,

If you take a look at the photos posted by Adrian Whiteman, look in particular at the 3rd and 4th photos. They show and early TT set-up with a pinon shaft and 2 pinion gears. In later TT's, starting in 1923 I think, theses parts were replaced with a pinion spider and 4 pinion gears. Also, the differential gear case halves were machined for the spider in the later version. Everything else stayed the same.

I'm pointing this difference out because in your original post you ask for photos of the innards of a 17-27 TT differential. They are not the same for all years.

That is a good point.
This is the 'cage' that holds a standard axle spider gear together. The bronze gear wheel is sandwiched between two cages and the large ball bearings run in the axle housings.
The 'differential gear case' (cage) that hold the bearing and crown wheel also hold the spider gear pins, transmitting the power to the axles.
The TT does not have "inner" hyatts like the car does. Behind the roller bearing sits a cup with a felt seal to help contain the oil in the pumpkin.

The worm set up is the same on both standard and Ruckstell versions. There are 2 gear ratios, a "high speed" and a "low speed". These vary in the number of 'starts' in the worm and teeth on the bronze wheel. High speed is 6 'starts' and 31 teeth on the bronze, while the Low speed had 4 'starts' and 29 teeth. (the options make the difference between Slow and Really Slow )

Martynn: Looking forward to seeing your results. I googled 'model tt ford differential images' and a number of user-submitted photos along with the usual diagrams came up. Best, jb

Bronze Gear Wheel:
This is a 29 tooth (low speed) wheel. The 31 tooth gear is the same, just with closer spaced teeth.
Some wheels have the Ford logo on them (see below picture). This does not appear on all wheels I have seen.
There is sometimes a casting mark such as a capital letter "B" or small triangle pattern, but again this does not seem to be consistent.

SPIDER SETS:

Early (2 spider gears) and later (4 spider gears). The spider gears are the same size and pin is same diameter on both types.
Note that the early type has the pin milled on each side to give clearance with the axles. I have some with holes in the end of the pin to locate a small stud that fits in the in and the cage casting so that the spider pin cannot rotate.

Assembly of spider into cage casting:
Second cage side goes on the other side and all are bolted together (not forgetting to put in the axles )

Detail of cage casting:
The same one is used for each side.
Note the Ford logo and on the opposite side is "TT11"
The early cage casting is the same but with two 'gorrves, not 4, and sometimes with a hole in one side for the locating stud (see post above).
Roller bearing is a press fit, and I have not removed it from this spare - it is a simple boss on the side of the casting that can be seen in the center of the unit.

Martynn,,

You didn't say why you are planning to tear down your TT rear end, but the best advice anyone can give you on this subject is just dive in. As long as you're reasonably mechanical, it's actually a very easy project. The hardest part is wrestling the heavy parts around. Pay attention to how it comes apart, take pictures and it'll go back together easinly. Unlike other differentials, there are no settings at all. It just bolts together. Be sure to use new seals all the way around. There are 7 if I remember correctly, outer grease seal at the hub (2), inner grease seal just inboard of the outer wheel roller bearing (2), differential oil seal just outboard of the inner ball bearing (2), and input shaft seal (1). Actually, the hardest part of the whole thing as I remember was getting the axle shaft to slide over the inner oil seal.

In the unlikely event you get into trouble, there are always plenty of us here on the forum to help!!

Good lick and keep us posted!!

Hpetrino….I didn't say anything about tearing down a TT rear axle, I posted that I wanted pictures of the TT's differential gears. Mainly because I don't know much about them (I don't own one), so in order to draw this unusual rear axle I needed to see pictures of the components, this last batch from A Whiteman, were really great showing me exactly how the differential goes together.

I had long thought of the TT as a sort of boondoggle, and couldn't fathom why anybody would want this large slow moving behemoth. It is only after I pretty much finished my touring and started drawing the T subassemblies, that I began appreciating the design and function of the TT. A lot of the parts on the TT are Model T, but with slight modifications to accommodate its load capabilities (this also fascinated me). Then I colorized the cross section of the TT and came to understand that there were two different versions of this axle, a two pinon (which it seems everybody has) 17-22 and the 4 pinion (which seems more rare) 23-27, which made the truck stronger, insomuch as being able to install a secondary driveshaft and cross member amidships allowing the truck to haul 2 tons instead of 1 ton. This secondary driveshaft seems to be an Australian addition, rather than one used here.

Peter Kable asked me draw this assembly for a paper he was doing of the Olson Extension Shaft, so I cross sectioned it too (more for my own information than for anything he asked for), but really so I could make an isometric exploded assembly of it also (after all, it is what I do you know ).

Anyhoo, my desire for one of these vehicles has grown significantly since my project to where now I would really like to own one myself, where I would put it is a complete mystery to me, but one of these days (like an extra running Model T chassis) I mean to have one also.

Glad to help Martyn, I enjoy your cross sections immensely so pleased to help any way I can.

This sequence shows the worm thrust bearing assembly (rear end). I don't have a worm to hand but will dig one out to show the 'exploded' assembly for you too

(yes some parts here are a bit 'ropey' but still useful to show how it fits together )

Note the bit that seems missing from your drawings above is a spacer washer between the front thrust plate and the worm hyatt.
The ball bearings are fitted into a stamped steel cup that has the outside edges crimped over to retain the balls loosely. There is no spacer (shown orange) as in the draft drawing.

The Hyatt sleeve is not split like a rear axle one and has just one hole in the side for the locating screw to fit into (screwed in from the side of the right housing like a cam bearing stud).

Cheers, Adrian

(now to look for that missing ball bearing …………….)

Detail of the sleeve that joins the drive shaft to the worm pinion. Note the sleeve has a polished section where the felt seal runs. The seal sits in a cup at the end of the torque tube. A large washer sits between the felt and the front Hyatt bearing - just as is done between the rear Hyatt bearing and the thrust plate (see posts above).
The rear part of the sleeve is also recessed 1/2 inch as well. That allows the sleeve to slide over the pinion shaft where no grooves are machined for the polished section to support the felt seal.

Hazy memory here as I have been rebuilding Ruckstell axles that are a little different, but I think on the standard axle the fibre thrust washer goes between the inside face of one of the 'cage' castings and the outside flat of the axle pinion. Happy to be corrected on this.

Does anybody have pictures of the differential axle gear. This is the one that runs on the pinions and is mounted to the axle shafts. I know the end of the shaft is splined, so also probably is the gear too, but I need to see the teeth side, to see if there is a counter bore so as to be able to put those half round retainer locks on the shaft to lock the gear...I figured it has to have something like this to lock that gear on the shaft, that or it is a taper fit. I would just like to get this right the first time though (because drawing gears is a right old pain, even with my new program, although it is better than the original way I was doing it).

Also need a picture of the passenger side of the axle housing...got plenty of the other side, but would like one that is clean so I can see readily what is on the outside of that piece of the housing...otherwise I have to make a guess and no, those cartoons that are in the books wont help with what it actually does look like, because they are merely representations for descriptive purposes, not actual parts.

OK, here are my disassembly pictures.

Maybe I should've said this differently...what I want to see is the gear that is attached to the axle shaft, not the entire differential, I've got those, but the front side (teeth side) of that gear I'm fuzzy on, besides I need to count the teeth.

I appreciate what you posted Steven, especially those nice clean looking worm components and the Ruckstell part and the order of their assembly.
Do you see those gears that are on the ends of the axle shafts? Do you have a cleaned up picture of those gears? I need to see the teeth side straight on, the back side and a side view to get the angle...also if you've got any of the Ruckstell parts cleaned up, those would good to see too, especially the outside gear, just a straight on shot of it, so I can count the teeth.

Ford TT rear axle with gear




Ring gear for worm

Here are some of the axle gears.

Here are a couple more. I think that Dan's photos are from an AA rear but I'm not positive.

Martynn, both sides of the spider carrier are identical. Regarding a fiber washer, I don't believe that there is one like in a car rear end. Any of the rears that I have disassembled do not have them. The only fiber washer that I'm familiar with is in the TT Ruckstell rear. The gears are a very tight interference fit on the axle. Below are some more photos of the carrier.

Justin, thanks for the photos, they answered my questions...ok so the fiber washer isn't in a TT but in the Ruckstell version? Is there two of them or only one?

Do the ball bearings on the outside of the spider housing come apart, or so you just soak them to clean them? I haven't seen replacement bearings of that size from any of the vendors.

There is one fiber washer in the Ruckstell. The inner ball bearings are just soaked to clean them up. Unless a rear is full of water, those bearings are typically in very good condition.

This is the fiber washer as it sits in the Ruckstell rear. The thickness has to be adjusted to ensure the elimination of play and also allow free rotation when the assembly is together.

No the carrier bearing do not come apart. They are a thrust bearing like the car Ruckstell.

One more question...
Where does this part go? I gave it the title of "Spider Flange" but I'm not sure that is where it goes or does it go on the ball bearing?

That is the modern outer neoprene seal. It replaces the original spring steel and leather outer seal that is just inboard of the Hyatt bearing sleeve.

Those go each side of the axle at the outer end of each housing. First put that seal in ('bulgy side inwards') then insert the hyatt sleeve, then the hyatt roller, then the outer dust cap/seal.

Thanks guys, I had it totally wrong where I thought this thing went...there is some sort of rubber seal inside it yeah? Or is it just an "O" ring?

Hi Martyn, this contains a 'standard' modern style oil seal.