What to look for in a transmission

[psimet]

So I have the drivetrain torn down back to the transmission. I do have to replace the input shaft due to switching to the single plate clutch but what else should I look for or inspect? Do I just pull it and tear it down and clean everything? If so is there a good guide for what to look for?

I don’t feel like just replacing everything “just because”. Thoughts?

[Marshall V. Daut]

If the gear teeth are worn to points across their tips instead of being flat and there is pitting in their faces, it's time to replace those gears. I disassembled a transmission last week, whose teeth looked good. When the cluster gear was pulled out, the long bearing inside was missing one roller from its cage. It fell out at the same time, broken in two. I have no idea how the transmission acted previously because I had not driven the car. My bet is that it was noisy because of the damaged roller bearing. I suggest that even if your transmission looks good upon a cursory examination, take it apart anyway to check for hidden damage or wear. It doesn't take long to disassemble a Model A transmission once separated from the bellhousing and the U-joint has been removed from the rear. Check the two main bearings for smoothness and replace the gaskets. Make sure the little spacer ring is still on the snout of the main shaft. This often gets forgotten when a rebuild has taken place.
Marshall

[nkaminar]

I am not the expert on the multi disk clutches, but from what I have read, the input shaft has to be replaced when switching to a single disk clutch. There may be other changes. Search the Barn Forum for information.

Marshall has some good advice.

[Gene F]

It looks fine to me. Swap the input shaft (bearing too of course), clean the thing up and go. I have seen way worse.

[Bigsnapper43]

If my memory is correct the case must be changed also.

[Keith True]

Sponsored Links (Register now to hide all advertisements)

Yes,the case has to be changed unless you are capable of machining the bearing hole,and drilling and threading holes to hold the front bearing retainer/throwout bearing tube.You do know that you also need to change the bellhousing and pedals,right?

[Bigsnapper43]

I think the case must also be changed. That makes the input and the case ,Flywhell and pressure plate, clutch disc and throw out bearing necessary for this operation.

[psimet]

Yeah I had another thread about all of this. There seemed to be disagreement on the transmission case. I have another one.

Yes I have: flywheel, clutch, pressure plate, flywheel housing, pedals, throw out bearing, etc, input shaft, etc. still in process.

I still haven’t finished building the long block. Not much of a point in finishing things until I have everything done and everywhere I turn there’s something new. Was hoping to get away with existing housing. I do have another one so hoping that’s one I can repurpose.

[psimet]

Not the right side of the case but it’s the only picture I have with me. Maybe someone can tell from that. Otherwise I’ll grab a shot tomorrow at the shop.

[Mulletwagon]

Good time to change out the cluster and idler shafts for the O-Ring type. The throw out bearing and U-Joint are also good candidates for change if any wear is noted.

[ThirstyThirty]

If you can pull the trans and related parts, change input, then... I (me, too!) see no reason not to tear the entire assembly down, piece by piece, inspect and clean everything of everything to include the finite particles of crud that accumulate in any motor mechanical assembly's small spaces from many miles of use. replace what is worn or broken. look for any chipped teeth! done right, the reassembled assembly will be a source of pride and confidence!

a vs .

[nkaminar]

Psimet, If you can afford it, a Mitchell transmission with synchro on 2nd and 3rd is nice. You might be able to sell that transmission to someone who is restoring an early car with a multiple disk clutch.

[rackops]

I just took my transmission apart, inspected, cleaned, and replaced some of the parts. I watched George Bell's videos on YouTube and they were super helpful.

As far as a new transmission case, they're cheap and can be found in decent shape on eBay. I'd buy a single-disk case rather than trying to mess with the multi-disk case. Also, your input shaft is very different, so that will have to be replaced as well.

I'll take some photos later of the differences.

[katy]

Suggest you replace the front and rear main bearings w/new ones with a seal on one side. Put the "seal side" facing out.

[rackops]

Here are some photos of the transmission cases. The primer grey one is for a multidisk; the other is a single disk. There are enough differences between the two where it's worth spending $30-$50 to buy the correct transmission case instead of trying to get the multi-disk one to work.

[psimet]

Originally Posted by rackops

Here are some photos of the transmission cases. The primer grey one is for a multidisk; the other is a single disk. There are enough differences between the two where it's worth spending $30-$50 to buy the correct transmission case instead of trying to get the multi-disk one to work.

As I mentioned above I have another case I picked up with a bunch of other parts.

Interesting for me to note is that my multidisk case has shaft holes the same size as the later case, not the large shaft you’re showing on yours. I did see there were effectively 3 variants. My car is a Sept ‘28 car so after the switch in shaft sizes it appears.

[psimet]

Just got to the shop and the other case I have is drilled and bored correctly for the single disc setup it looks like.

[psimet]

Originally Posted by nkaminar

Psimet, If you can afford it, a Mitchell transmission with synchro on 2nd and 3rd is nice. You might be able to sell that transmission to someone who is restoring an early car with a multiple disk clutch.

I knew about their overdrive but I wasn’t aware until you posted this that they had a regular transmission with synchro. Project is already $$ for now. Between what I can find for a price and waiting 1-1 1/2 years I think I’ll just rebuild it as it was. I don’t plan on driving it a ton outside of short trips.

[psimet]

Originally Posted by Mulletwagon

Good time to change out the cluster and idler shafts for the O-Ring type. The throw out bearing and U-Joint are also good candidates for change if any wear is noted.

I have to change the throw out due to changing to the single disc clutch anyway.

I pulled the u-joint and it’s one of the early ones that’s riveted together. I didn’t take many pictures as it seemed in decent shape and I didn’t realize there were 2 designs.

Also just checked and everyone is out of u-joints …. So…. Anything in particular I should check for in assessing the one I have? Doesn’t seem like there’s much is any play or backlash in it but looking for guidance here.




Took the pictures because I noticed the lock washer was completely flat and off center.

[Mulletwagon]

Some caution with U-Joints. The best ones are NOS USA made. My joint was bad so I ordered one from one of the standard suppliers. It was made off shore and had more play than the unit I was replacing. I was fortunate to locate an NOS unit from another Model Aer that answered my May Day. If your joint has very little or no play, and you csannot locate an NOS non-rivet type, certainly use what you have to get your ride back on the road but be on the look out for a quality replacement. Enjoy following your rebuild !

[psimet]

Tore down my existing transmission. Looking for some input regarding condition on these gears. On a scale of 1 (replace now)-10 (those are perfect) how would you rate them?








The cluster gear is worse than I first thought unfortunately. I have another and I’m hoping it’s in ok shape.

[Marshall V. Daut]

Bite the bullet and replace those gears. They're toast. Would you really trust them? There will never be a better or less expensive time to replace those gears than now: the transmission is out, it's disassembled and you've resigned yourself to investing money in it. New gears will cost a bunch more down the road after the tranny fails. When will all the stars be in alignment again like this?
Marshall

[Brentwood Bob]

Pm sent.

[psimet]

I was looking through this doc https://www.santaanitaas.org/wp-cont...ugust-2018.pdf
..and noticed they bead blasted all the gears. Is that fine? I have glass bead loaded in my blast cabinet but wouldn't have thought of bead blasting the gears. I have an input and main shaft that could use it...

[psimet]

Time to round back on this one. Like with everything I undertake I learned way more than I had anticipated.

Thanks to a member here I was hooked up with Steve Mitchell. Great guy and a helluva resource. He was able to supply me with used gears in good condition. I bought the rest of the parts. The same family I bought my rebuilt engine from had a sale to help part out his remaining stockpile and i was able to pick up a lot of transmission parts.

I used that case that I mention above. Glass bead blasted everything I was re-using (the reverse idler, main shaft) as well as the input shaft, front bearing retainer, rear bearing retainer etc. I found Ford Script on so many of my parts under all that grease an oil.





I cleaned and nickel plated everything I could for the tower. With the help of my son I got it built the other day.





Got the safety wire and e-brake pawl done today. Now to get it back in the car and start installing all the rest of this stuff I’ve been busy restoring…

Reminder of what it used to look like:



And way back when I first started working on the car

[Brentwood Bob]

Sponsored Links (Register now to hide all advertisements)

Like the mushroom shift knob to finish off the restoration.

[psimet]

Originally Posted by Brentwood Bob

Like the mushroom shift knob to finish off the restoration.

Thank you. It’s the one that was on there. I just buffed it up. Single family car so I wanted to have my hand on the same shift knob my uncle and my great uncle used when they drove it.

[Synchro909]

When I took delivery of my 1928 Tudor, I checked everything before starting it and found that the oil in the gearbox was LOW. The teeth of the big gear at the front of the bottom shaft were just dipping oil. Every tooth in there was pitted and the oil that was in there was full of sparkly bit of gears. In the whole time he had owned he car, the previous owner had not checked the oil. .
These gearboxes are tougher than we expect. I flushed it several times till I got almost no metal flakes when I drained it and installed a magnet on the drain plug. I put a set of new bearings though it and drove on. Nearly 20,000 miles since and it is still going just fine with no nasty noises. If $ are short, IMO, there is no need to replace much in there now. It can wait.

[psimet]

Originally Posted by Synchro909

When I took delivery of my 1928 Tudor, I checked everything before starting it and found that the oil in the gearbox was LOW. The teeth of the big gear at the front of the bottom shaft were just dipping oil. Every tooth in there was pitted and the oil that was in there was full of sparkly bit of gears. In the whole time he had owned he car, the previous owner had not checked the oil. .
These gearboxes are tougher than we expect. I flushed it several times till I got almost no metal flakes when I drained it and installed a magnet on the drain plug. I put a set of new bearings though it and drove on. Nearly 20,000 miles since and it is still going just fine with no nasty noises. If $ are short, IMO, there is no need to replace much in there now. It can wait.

We did a spring safety check for our local club. It was fun and really got me laying eyes on the mechanicals on a lot of running A’s. At first I was shocked at the number of them that had low or almost no oil in the transmissions (along with loose wheel bearings, no grease, low oil, etc).

I’m in the cycling industry and we have the same thing with people that just ride their bikes and never do maintenance or think of repairs. My favorite quote from that crowd is, “I have people for that”. In that world I’m their “people”.

It slowly made sense to me that even though so much of this hobby is centered around working on these cars there is still a heavy dose of “I have people for that” sentiment and general neglect of routine maintenance.

I left that safety check once again reminded that as long as you throw something remotely flammable in the engine that these things really will keep running.

After spending all this time I absolutely would have kept running the gears I originally had but I am glad that I did swap them for this restoration.