Hey all,

In the process of rebuilding the flathead in my F-5, we pulled the transmission while the engine was out. Disassembled (mostly) the trans last weekend, and I am surprised by the amount of wear. There is a LOT of wear to the 2nd gear slider. There is some pitting on the inside of the case, where the secondary shaft thrust washer contacts it, and there are numerous small dents (for lack of a better word) on the secondary shaft where the roller bearing run. There was a lot of metal flake in the transmission oil, plus some pieces of metal maybe the size of sand.

We had driven this all of 4 miles, and did not get it too shift well, but that may be due to operator difficulty (not having driven this before), engine running extremely poorly, and perhaps the transmission condition. This truck had sat outside for many years before I purchased it.

Question is: Is it worth reusing this transmission? Or getting another used one? How much better might I expect a used one to be? If reuse, I already have new main bearing, the rear seal, and gasket; and would think new thrust washers are called for.

Any thoughts are appreciated. Photos below:

Duane.

1st - 2nd gear slider, showing wear on 2nd


1st - 2nd slider, showing wear on individual teeth


pitting and wear in inside of case


wear on outside (case side) of thrust washer (left one matches case photo)


wear on secondary shaft (right side in picture is where roller bearings run)

 

Is the case thrust face cleaned up? That mostly looks like debris, but maybe the slot for the tang is chipped? It doesn't appear the thrust washer was spinning. That is the key issue IMO, really costly to repair the case at that area. Your teeth show pretty typical wear from grinding, but no chips? All the parts are pretty easily available, AFAIK. (and not too expensive -- just depends if you want to keep it)

 

As Ross said, that looks pretty typical for straight cut gears....
I would consider installing a T98 syncro trans if you can find one. Depends on how much you will use the truck....

 

Ross,

The case thrust face definitely has some pitting and protusions on it. It is more than just debris. The slot for the tang might be chipped, I'm not sure and the picture is not great. But I agree it does not look like the thrust washer was spinning. I think the washer would be more worn than it is if it were spinnign. I am thinking that the case could be improved by filing off the high spots carefully.

In terms of the gear teeth, there do seem to be some small chips that have come off (sort of visible in the second picture), and to me the second gear slider shows some spots that look almost ready to chip off some more. Maybe I should replace that 1-2 slider gear. The one price I saw on it is $140 at Van Pelt sales, have not checked my regular source (Chuck's Trucks) yet.

Not yet sure how I will end up using the truck, but it is unlikely to get extensive use. On the other hand, I do want it to be reasonably drivable.

Scott, do you know if the length of the T98 syncro trans is the same as the regular 4-speed? Without redoing a lot, the space is limited by location of the transfer case, which allows for a very short driveshaft between trans and transfer case. It would be beyond me (at least at this stage) to move the transfer case.

Thanks,

Duane.

 

I was thinking the same, that you'd never have room without moving the transfer case. Which then involves drive shafts and linkage. As many spur transmissions as there are being junked you should have no problem finding replacements. I'm gonna follow your progress because it'll be me too. Stu

 

You're bound to have damaged teeth, smoothing the chipped areas won't hurt. Check eBay, and people on here for spares, but the ones I've seen on here are usually full of water...

Here's what a truly chipped tooth looks like. It still didn't make noise

 

I aggree with Tinman find one from a 51,52 and you will be so happy. T98

 

Duane, the T98 may be slightly larger but very little I think. What is different is how the trans mounts.......T98 has a lower rear mount that sits on a hoop type x member under the trans. I am not familiar with the trans mount on larger '48-'50 trucks. Since your truck is 4x4, that may change everything...

There has been discussion of this subject on here in the past, but by whom I don't recall. Maybe try a search?

 

I'd suggest a phone call to Chuck, if you haven't done it already. He should know whether it'd fit without heroic measures to move the transfer case. Stu

 

Yeah. And if you lived on the Left Coast, you could come over here and I'd have a good T-98 for you for practically nuthin!!

 

You should be able to get another crashbox for free with a bit of patience. Hot rodders like the short removable clutch cover / bell housing / hogs head and usually throw the rest of the transmission away.

 

Thanks for all the suggestions and offer if I was on the other coast. I cannot see anything indicating transmission length in the parts book. I will plan to ask Chuck about the length of a T98 vs crash box, unless he finds this thread and jumps in. I'm leaning towards making some improvement, whether finding another crash box, replacing a gear or two, or possibly the T98 route if feasible with the transfer case. I will likely check with the previous owner of my truck, as he had a large number of spares, and likely some transmissions.

Duane.

 

Duane,
The 1950-52 T-98 is about an inch longer. You have to move the transfer case back to make room for it. M-H actually added an "S" to the model number of trucks with this transmission, since it effected so many other components.
Chuck

 

Chuck,

Thanks for the info on length.

I think I will stick with the regular 4-speed. I will check with the original owner to see if he has a better one.

Duane.