What are the external differences between the crash box and synchro trannies?

Can a T98 replace a T9 without changing anything (like the drive shaft)? I really doubt that it would be that easy...but just wondering.

 

all T9's have the small ears and are set up for the small cross member of the F1, T98's (most but not all) I believe have the large collar setup for the "big hoop" crossmember of the F2+ size trucks... could be wrong, but that is what my research has shown. I have seen pix but not actual trans of T98's setup for F1 use (small ear collar). is there something specific on your mind - do you have a spare T9 laying in the back 40?

 

I think I read the parts book correctly and have the T9 / T98 designation straight for the '51 F4. As I'm reading both parts books, the T9 is a 4 speed spur gear tranny and the T98 is the synchro 4 speed.

On page 329 of the Text Catalog, the '51 4 speed identification number is T9 with part number A8T 7001-B.

The Illustrations Catalog shows the insides of this T-9 on page 195, but nowhere can I find a picture of the case.

The synchro 4 speed is depicted on page 196.

Am I going crazy?

 

The T9 is also the 4 speed spur used in the F-2/3s which have their own unique transmission cross member. I don't know up from down about the T98, but have read that it is somewhat longer than the T9. Which would mean driveshaft mods at minimum I'd suspect. Stu

 

I have found two good discussions about this:

https://www.ford-trucks.com/forums/8...-question.html
https://www.ford-trucks.com/forums/9...ty-t-98-a.html

 

Joe,
how long is your driveshaft ? And where is the center bearing located where the two pieces come together?
That 47 truck you saw at my storage yard maybe could donate the driveline if its the correct length?
But im guessing its too long.
If you end up going t98 may just be easier to shorten your existing line a couple inches??

 

Yeah Joe, don't avoid a transmission improvement switch because of drive shaft mod required.
And then while you're modifying the driveshaft, why not just install an overdrive unit to make Betsy more road-able.

 

Now, finally, we're talking! That's just good all over (under?).
As for Albatross, rebuilt 292 and T98 go in first, drive it a while, find an overdrive when the purchase is right.
I fear dropping big money into an older overdrive box that I'll then have a hard time finding parts for. I may go the Gearvendors route with a divorced unit. Big money but it'll drive home if it does break and it would have warranty and reasonable parts availability.
Of course, going faster mandates good braking!

 

Thanks for the links. I asked the question before I tried doing a search. Again

I need to get the top off my T9, check the gear teeth and see if it needs to be pulled out. I should really stop asking questions about trannies until I've determined what I need to do.

Thanks for all the replies guys.

 

the "ears" on the T98 point towards the front of the truck, indicating that the T98 is longer, and sits more above the crossmember. The T9 is shorter, and the "ears" point backward. The T9's "ears" piece is bolted on by 5 bolts and can interchange with the F2/3 and F1 versions. The T98 piece may also bolt on, but the forward pointed ears prevent it from mounting onto anything but an F4-6 size dropped crossmember. The driveshaft is the same (for 134" or 158" wb), but the intermediate shaft between the carrier bearing and trans mounted parking brake might be different in length. I have both, and can measure them when I have daylight.

 

Thanks Havi.

I'm at a loss when you talk about the "ears". With little understanding of these transmissions, I can't picture anything to call ears on the case. Can you help me out with that?

I think you're saying that to swap a T9 for a T98, I'd also have to change the crossmember. And probably the intermediate drive shaft will be too long because the T98 is longer.

Am I making sense?

 

These are the "ears" and "feet". On the left, the F-1 rear mount; the others are used with the deeper crossmember on the same trans. Can't find any pics of the T98-A for a BB truck.

 

OK, I see what Havi was talking about now with the ears pointing in different directions.

Here's the synchro pic. Thanks Ross and Havi. I'm learning...

 

I was using the term "ears" to coincide with what Brain75 was referring to. I didn't get home from work today until after dark, so I'll try to measure the shafts tomorrow.

 

Bryan, I have a T9 in my stock F4. I read your post but missed this question. So, I guess I didn't really read your post.