Transmission parts swap

[coW52Dodge]

My transmission had bad syncros so decided to finally pull it and switch it out. Assuming the number at at top relates to a build date, my old transmission was made in 51 and the new one made in 55.

They look identical at first glance. After struggling to get the new one in, I pulled it out, made sure everything is still lined up and tried, tried and tried again.

That thing has been in and out three times now and the last 3/4 inch just won't go in.

On a positive note, I'm getting good at pulling transmissions on this truck.

Well, after pulling it out one more time today, I decided to measure the input shaft. The new one is almost an inch longer than the old one, from about 6 3/4 to 7 3/4! The housing is also significantly longer.

Assuming the inside is similar (does anyone know?) , how difficult would it be to swap the input shaft, replace its bearing, etc?

Or should I just fix the old one? Or maybe look for another candidate?

[coW52Dodge]

Oops - just noticed this isn't the pilothouse forum. Sorry about that.

Could a moderator move it for me?

[meadowbrook]

could it be you have a fluid drive trans?

[coW52Dodge]

could it be you have a fluid drive trans?

I don't know. Is there an easy way to tell? The numbers on the top are different but figured they were date codes.

The input shaft's housing on the new one is a bit longer, along with the overall length of the input shaft.

The bosses that hold the parking brake assembly are offset in height on the original. On the new one, they are on the same plane. To make that assembly fit, I had to elongate both mounting holes on the original bracket.

It is a shame this one doesn't fit because it has a nice positive 'click-in-gear' feel to the gear lever.

[moose]

I had the same issue on mine. Fluid-drive trans going into a truck bellhousing. I didn't have another choice, so I just carefully cut the input shaft back and slightly bevelled the edge. I'm not necessarily recommending that you do this, but it is an option.

[Merle Coggins]

Were they still using Fluid Drive in the trucks in '55? I kind of thought that they went away from that by then. However, if it is a fluid drive trans, and you can swap out the input shaft with your original trans, I'd be interested in getting that input shaft and related parts to possibly convert a 4 speed trans that I have into a Fluid Drive unit. You trans is a 4 speed isn't it? I don't remember now.

Merle

[coW52Dodge]

Were they still using Fluid Drive in the trucks in '55? I kind of thought that they went away from that by then. However, if it is a fluid drive trans, and you can swap out the input shaft with your original trans, I'd be interested in getting that input shaft and related parts to possibly convert a 4 speed trans that I have into a Fluid Drive unit. You trans is a 4 speed isn't it? I don't remember now.

Merle

I'm just assuming that it is a 55 because it has this on the case. Maybe it means something totally different, though:

The new (fluid drive?) transmission's input shaft dimensions:

My original old transmission's input shaft dimensions:

I've already contacted someone that has a transmission that may just fit in so may just replace the transmission. If you can use the 'fluid drive's input shaft with these dimensions, you're welcome to them parts, Merle.

[Dodgeb4ya]

The fluid drive input shaft is much bigger and longer.

Bob

[coW52Dodge]

The fluid drive input shaft is much bigger and longer.

Bob

That does look much longer. I do wonder why they have so many permutations of a simple transmission, though.

[moose]

That does look much longer. I do wonder why they have so many permutations of a simple transmission, though.

Yeah, that's not what mine looked like either. I wonder what it did come from. I thought it was from the 46 Dodge I got the motor from? I guess maybe that's how you know you've got too much stuff from too many places. Oh well, it works now...

[Young Ed]

That does look much longer. I do wonder why they have so many permutations of a simple transmission, though.

I know for the 49-54 cars they shortened the transmission instead of the driveshaft for the short wheelbase cars. No idea why. I'm sure thats not whats up with your truck transmission but still odd

[james curl]

I believe the 57 and up cars used an entirely different transmission based on the bell housing for the V8. I was offered a running six with an overdrive transmission at the Pate swap meet two years ago for $100.00 and did not take it but did talk a fellow flat six owner to buy for his 35 Plymouth. The transmission had different shift arms than the older transmissions. The 57 through 59 transmission had two operating arms that were parallel and at the bottom of the side plate, completely different than our early transmissions.

[Merle Coggins]

I meant to get some measurements and pictures of the input shaft of my trans the last time I had it out (for a clutch job), but I remembered it after it was all back together. However, I agree with Bob that the FD input shaft is considerably longer than what's on a straight clutch trans. And as he shows the added length is mostly from the splines to the pilot bushing, with a second bushing surface in between.

Merle

[Paul Hoffmeyer]

If the "new" tranny is from a '55 V8 truck, it will have an input shaft about an inch longer, and the bell housing will also be about that much deeper.

Paul H

[coW52Dodge]

If the "new" tranny is from a '55 V8 truck, it will have an input shaft about an inch longer, and the bell housing will also be about that much deeper.

Paul H

Aha - mystery solved.

Would you happen to know whether the input shaft and related gear, bearing, housing, etc could swap with an older V6 tranny?

[coW52Dodge]

Aha - mystery solved.

Would you happen to know whether the input shaft and related gear, bearing, housing, etc could swap with an older V6 tranny?

Duh, just noticed I described my engine as a V6.

In my defense, I'm an idiot sometimes.

Clearly, I meant to type 'an older 6 cylinder-type tranny that we usually see in Pilothouse trucks'.

[coW52Dodge]

A friend of mine pointed me to this document regarding rebuilding of New Process transmissions.

This particular trans may be a little different than the ones used in our vehidles but it is still very good info so posted it here, in case someone else can use it.

[coW52Dodge]

Okay, after two weeks of honey-do kitchen replacement work, I decided to take a break from that mess and do some fun work on the truck again.

Both input shafts are out and they look like they should just swap: In the picture, it is clear that the length is drastically different but the gearing looks the same, size of the gearing the same, bearing should fit the hole - done deal. The housing also seems to swap nicely.

One weird thing: the 'new' transmission does have this ^washer^ between the input shaft and the main shaft. The 'old' transmission does not have one.

It looks like a split washer that has seen better days - it has split more than is normal I think.

Why would that be a split washer?

If it serves as a spacer, shouldn't it just be a regular washer?

[Scruffy49]

Old style lock ring. Think internal snap ring. At least, that's what it looks like. When I grenaded my last Chevy 4 speed those rings were everywhere inside the case.

[maverick]

that ring appears to be the internal snap ring that holds in the needle bearings between the main shaft & pilot shaft

[coW52Dodge]

that ring appears to be the internal snap ring that holds in the needle bearings between the main shaft & pilot shaft

Thanks for the suggestions, guys.

Both input shafts have caged needle bearings but they just slide out easily. I've tried figuring out where it might go but there's no groove around anywhere to slide it into.

I've put the shorter shaft into the new transmission and it appears to operate normally. Maybe someone used it as some sort of spacer or something, using what was available.

It is just weird that one transmission had it, the other did not.