8 3/4 without a pinion gear? can you do it?

[YY1]

OK, here's the scoop-

One of my friends has one of those trailers made from an old truck bed.

It's ford bed, but it's riding on what we can best determine is an A-100 chassis.

Here's the kicker- This thing's been riding around for at least 15 years with an 8 3/4 axle...

...with 3.55 gears!

He's asked if I'm interested and I kind of am, but I don't have anything to swap into it.

If I had a 2.76 in a 741 I'd swap it out and be done.

I do have a 7 1/4 complete axle, but it's on a parts car that needs to move and the A-100 would be too long to swap in. Plus we're now talking about 2 days labor.

I thought about just taking out the ring and pinion, leaving the chunk so the carrier bearings can still support the inner axle ends, but...

That leaves the hole where the pinion shaft is supposed to be.

I hate like heck to weld up a plug and possibly ruin an 8 3/4 chunk, but a cheap set of 3.55 gears for the next time I have a 741 case is pretty tempting.

It's also a crying shame to let that go under that trailer again for who knows how many years.

Any ideas?

 

[Cranky]

Swap in the 7 1/4!! But you could plug the pinion hole with a piece of wood. Has to fit right though and then seal it with some RTV. Probably would last another 20 years lol

 

[rick68b5]

Take the seal and weld a piece of sheet medal to it done deal

 

[Bb70charger500]

I got a 8 1/4 in that parts car it will be getting pulled once the cars on the trailer bring me $50 and some help you can take it 74 charger
I'm almost 100% I think it's 54" backing plate to backing plate

 

[YY1]

The issue with A-100 rears is they have B body perch widths and C body flange widths.

I really don't have the time to pull my parts car axle and then worry about if the wheels will rub the inside of the truck bed, and if I can get something to put back on the parts car.

He want's to put this up for sale in the next few days.

I wish there was some way to fab an center bearing and just put a plate over the diff hole.

So fay I like both other suggestions.

Weld or seal something to the seal seems relatively easy, and so does a sealed wood plug.

 

[mmissile]

That's a lot of work for some used innards.

 

[Cranky]

Just realized what you said about a Ford bed riding on an A100 chassis.....the A100 is a unibody vehicle so how is he using a Ford bed on one?

 

[PurpleBeeper]

OK, well I will go upstream..... I suggest you pull the center-section out of any 8-3/4" you find in the junkyard to swap out. It's not "that" tough. The ring/pinion isn't worth all that much, so to me, the only real value is if you have the center section in tact with the gears already set up in it.

 

[moper]

You certainly can remove the ring and pinion. Then just make a plug for the pinion hole with a PVC pipe cap or something. The carrier has to stay in place. The ring and pinion don't.

 

[YY1]

When's the last time anyone saw "any 8 3/4" in the junk yard.

This is the closest thing in decades for me.

Are you sure A-100 in uni?

Maybe it's a regular truck frame then.

We dated the 741 as pre-mid 1968 and the axle measurements are inline with an A-100 and not a D100/150.

I also know the A-110 to be very likely to have a 3.55 rear gear, esp with a/6.

Not sure about D100/150 as I think there's a higher percentage of 318 engines in them.


Yes, it's some trouble, and some innovation, but pulling the axles and the chunk to get a cheap 3.55 set is fairly easy and beats letting it get sold with that in it.