Transmission Weight & Suggested Items

[amcordo]

Hi everyone!

So I'll be pulling my transmission and doing my own fix in a couple of weeks. This will be my first time doing transmission work so I've blocked off an entire week to do it since it'll probably take me some time.

I have the gears I need to replace (third gear has some stripped teeth), but what items (seals, bearings, etc.) do you suggest I replace by default if I'm opening the transmission? I want to make sure I have everything ready before I get my hands dirty.

How much does the transmission weigh? I do not have an engine lift. Will I be able to remove the transmission without one? Or more specifically, would I be able to open the transmission to swap out the third gear or any other parts without removing it?

[Mike Koch]

The complete transmission unit(including the transfer box) weighs about 225 lbs.

[amcordo]

Darn, just a bit heavier than I can lift....

The complete transmission unit(including the transfer box) weighs about 225 lbs.

[pisten-bully]

Or more specifically, would I be able to open the transmission to swap out the third gear or any other parts without removing it?

It's gotta come out. If you're chassis is a replacement frame chances are there's a removable x-member underneath and you can drop the gear box out instead of taking it out the top... a preferable operation for sure.

Replace the clutch disc at least as long as you're there!

[Linus Tremaine]

you should

Replace the lay shaft. These are small to begin with and snap off after so many years of service especially in a heavy 109. Replace the 3rd/4th synchro cluster- I would think synchros should always be replaced when opening a gear box. Change the bushings on the gears of the main shaft and the snap ring on the main shaft incase it is worn. Inspect first and reverse carefully and replace if needed.


I guess you said you were fixing it not rebuilding it!

[amcordo]

Thanks for the helpful advice! So I'm looking through the RN catalog and I hate to say this, but the only thing I can identify from your suggestions immediately is the syncro cluster. There's a ton of layshafts, no bushings (does this mean bearings?) and nothing called a snap ring.

Layshaft - which one(s)?
3rd, 4th synchro cluster - check
Bushings - do you mean bearings? Which ones?
Snap ring - Does this mean #16 sealing ring?

http://www.roversnorth.com/store/c-51-gearbox.aspx

Sorry - I'm clearly a novice at this, just excited to learn!

Replace the lay shaft. These are small to begin with and snap off after so many years of service especially in a heavy 109. Replace the 3rd/4th synchro cluster- I would think synchros should always be replaced when opening a gear box. Change the bushings on the gears of the main shaft and the snap ring on the main shaft incase it is worn. Inspect first and reverse carefully and replace if needed.


I guess you said you were fixing it not rebuilding it!

[Bertha]

Thanks for the helpful advice! So I'm looking through the RN catalog and I hate to say this, but the only thing I can identify from your suggestions immediately is the syncro cluster. There's a ton of layshafts, no bushings (does this mean bearings?) and nothing called a snap ring.

Layshaft - which one(s)?
3rd, 4th synchro cluster - check
Bushings - do you mean bearings? Which ones?
Snap ring - Does this mean #16 sealing ring?

http://www.roversnorth.com/store/c-51-gearbox.aspx

Sorry - I'm clearly a novice at this, just excited to learn!

The trans parts you purchase are dependant on the suffix stamped on your trans case: A B C etc. With that info you will be able to buy the correct gears. The layshafts are a must for replacement and I am sure the idler gear will be toast as well. Check the gears for any metal fatigue by eye: any pitting or break down in the metal surface will necessitate a gears replacement. If unsure about the gear, take a good picture and post it up for advice.

[pisten-bully]

Don't hesitate to phone the guys at RN and get their suggestions! I just looked at the parts book on-line and it looks rather intimidating (confusing, too)... much more intimidating than when you actually crack the thing open and do the job!

[amcordo]

Thanks! I need the encouragement...

Don't hesitate to phone the guys at RN and get their suggestions! I just looked at the parts book on-line and it looks rather intimidating (confusing, too)... much more intimidating than when you actually crack the thing open and do the job!

[JackIIA]

Can anyone comment alittle more on the Layshaft and Mainshaft replacement points?

I'm right in the middle of an overhaul and had not planned to replace either. They look OK - no scoring or evident abuse. The truck does not see heavy offroading or towing.

So...I know I'm pandering for the answer "you don't need to replace the shafts", but are beliefs that replacement of the shafts necessary based on useage, mileage, visual? Thanks!

[Mike Koch]

If you replace the clutch, don't forget an alignment tool:

[greenmeanie]

The shafts by themselves only need replaced if they are worn or damaged. It is up to you to decide if you have the knowledge or confidence to identify wear or damage on a shaft. If you don't know or are not confident and you want to ensure your good, get a new shaft.

When inspecting the shaft pay particular attention to the splines. Alll the teeth should be straight with no worn steps in them. Next look at the bearing journals which should be smooth and clean. Next pay attention to any place wher the shaft changes cross section i.e at each shoulder. Look for hairline cracks or gouges.

In my opinion any time you have the gearbox open and the shafts out it is far more important to replace all the bearings than the shafts. Bearings are the real moving parts that will react badly to abuse or poor maintenance. Any time you remove a bearing from a shaft with a puller (I.e. if it is not just a slip fit) it needs replaced.

[pisten-bully]

Think of it as insurance... most of the effort goes to getting the gearbox out, so as long your at it why not do it "right"? And if you ask ten people the definition of "right" you'll probably get eight different answers! Ask the RN guys what they think, but doing the bearings is "right" ...and I think you'll find it's more common for a layshaft to break (old age... it can look great and then wham) than it is to find the mainshaft breaking. And that's my opinion.

[amcordo]

More on the layshafts...

Are there multiple of these? What function do they perform? If there are multiple in the transmission, are there particular ones that are more likely to wear out?

Thank you everyone for your great information!

[JackIIA]

Gents - thanks for the great advice as always.

Amcordo - no, there's only one layshaft and one mainshaft in your transmission. The layshaft is basically bringing in the power from the engine/clutch and then through the set of gears on it, transfering that power to the mainshaft (which also have matching gears for 1st, 2nd, 3rd). I'm sure others can give you a better description. If you have the Green Bible check out page 16-C to 20-C. They have some nice schematics of the transfer of power between the gears, 2WD, 4WD, and High/Low.