Opinions on Transmission Rebuild

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
User avatar
17thAirborne
G-Lieutenant General
G-Lieutenant General
Posts: 5847
Joined: Mon Jun 21, 2004 5:42 am
Location: Central TN

Opinions on Transmission Rebuild

Post by 17thAirborne » Wed Jul 08, 2020 1:29 pm

Not having a lot of rebuilds under my belt, I am wondering what the educated and prevaling philosophy is on rebuilding transmissions and geared components.

If you have one crappy gear and one worn shaft, do you replace ALL of the gears and shafts to keep things "tight" or do you replace the worn components only.

I'm dealing with an early GPW gearbox that has some wear to some components, needs a few bushings and a few other parts. Although money is not the overriding concern, I don't want to spend extra for the sake of having everything new.

Although it does not always apply, "If it ain't broke, don't fix it" the old Army addage works most of the time.

I look forward to some discussion to usher me along the right trail. 8)
Oz

Feb 43 GPW 98532 USA 20206257
Oct 70 Land Rover Series 2a 25334079G NZ16GF36
http://gpw.castraponere.com/ (My Restoration Page)


dinof
G-Major General
G-Major General
Posts: 2860
Joined: Fri Jan 08, 2010 4:32 pm
Location: Arcadia & Johannesburg Ca.

Re: Opinions on Transmission Rebuild

Post by dinof » Wed Jul 08, 2020 1:40 pm

Next time I rebuild my transmission, it will only be what's broken. And since there is a lot of out of spec parts out there, I'm going to do just that. But....I don't drive mine much so a used gear that is still good will last forever on my jeep.
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43
1928 Model A Roadster Pickup
1930 Model A Tudor
1968 Taco Minibike

User avatar
17thAirborne
G-Lieutenant General
G-Lieutenant General
Posts: 5847
Joined: Mon Jun 21, 2004 5:42 am
Location: Central TN

Re: Opinions on Transmission Rebuild

Post by 17thAirborne » Wed Jul 08, 2020 2:32 pm

dinof wrote:
Wed Jul 08, 2020 1:40 pm
Next time I rebuild my transmission, it will only be what's broken. And since there is a lot of out of spec parts out there, I'm going to do just that. But....I don't drive mine much so a used gear that is still good will last forever on my jeep.
Thanks for that insight. I don't plan on driving mine under combat conditions as well, so perhaps a more gentle touch will allow the old, but not damaged parts to continue serving.
Oz

Feb 43 GPW 98532 USA 20206257
Oct 70 Land Rover Series 2a 25334079G NZ16GF36
http://gpw.castraponere.com/ (My Restoration Page)

donk_316
G-Major
G-Major
Posts: 941
Joined: Sat Sep 03, 2011 5:47 pm
Location: Edm, Canada

Re: Opinions on Transmission Rebuild

Post by donk_316 » Wed Jul 08, 2020 2:38 pm

Is the issue funds? Or just time and effort?

If it’s apart on the bench, just do it all and never worry about it again.


Sent from my iPhone using Tapatalk
GPW 112092 04-30-43 USA 20372531 (orig)

dinof
G-Major General
G-Major General
Posts: 2860
Joined: Fri Jan 08, 2010 4:32 pm
Location: Arcadia & Johannesburg Ca.

Re: Opinions on Transmission Rebuild

Post by dinof » Wed Jul 08, 2020 2:52 pm

donk_316 wrote:
Wed Jul 08, 2020 2:38 pm
Is the issue funds? Or just time and effort?

If it’s apart on the bench, just do it all and never worry about it again.


But I'm sure that if the transmission had say 5,000 miles on her and your case was a bogus counterfeit WOF that is causing troubles, your just going to change the case right? Sure you inspect for anything bad, but the way parts are being made? It's a jungle out there :o
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43
1928 Model A Roadster Pickup
1930 Model A Tudor
1968 Taco Minibike

User avatar
17thAirborne
G-Lieutenant General
G-Lieutenant General
Posts: 5847
Joined: Mon Jun 21, 2004 5:42 am
Location: Central TN

Re: Opinions on Transmission Rebuild

Post by 17thAirborne » Wed Jul 08, 2020 3:15 pm

It is apart on the bench. Am currently inspecting each part for wear and servicability. If i replace every internalpart in the transmission transfer case and engine, yes, that could be expensive, and then I may have a pile of serviceable parts that may have worked just as well.

I guess the question should have been is it neccessary to replace ALL parts so as not to cause damage or premature wear with a mix of old and new components.

I have also read the various threads echoed above regarding the "jungle" of new parts out there that are failing. NOS is hard to find and so we are forced to either reuse or buy the repro.

Just adding up the small parts, bushings, washers, spacers shafts and a gear or two it gets well into $500. I;m not complaining, just seeing if it is critical to not mix old and new when rebuilding these.
Oz

Feb 43 GPW 98532 USA 20206257
Oct 70 Land Rover Series 2a 25334079G NZ16GF36
http://gpw.castraponere.com/ (My Restoration Page)

bazza46
G-Colonel
G-Colonel
Posts: 1550
Joined: Sat Aug 12, 2006 4:28 pm
Location: Sydney, Australia
Contact:

Re: Opinions on Transmission Rebuild

Post by bazza46 » Wed Jul 08, 2020 3:48 pm

I'd only replace components that have obvious wear on them. For instance, any gear that has brinelling (pitting) on the case hardened teeth should be replaced.

The main shaft nose where it runs on the rollers in the input shaft must be absolutely smooth and unmarked by brinelling or any visible faulting of the case hardening. Likewise, the inside surface of the input shaft, where the rollers run has to be completely free of marks or pitting.

In short, any faults in the case hardening should result in discarding the gear or shaft. Because these surfaces are subject to extreme pressure on the surface when the gearbox is in use. If there is any pitting or damage to the face of any gear on the cluster means it should be replaced, as simply installing a new new gear which meshes with the pitted one on the cluster gear will quickly wear.

Rust spotting or light pitting of shifter rails is not a cause to replace, as they just slide back and forth, and the pitting will just hold more oil to lubricate them. The same applies to shifter forks.

Countershafts showing wear that you can feel by running your fingernail over the edge should be replaced. All countershafts wear pretty quickly, and a replacement one will probably not be any worse than the one you're replacing in terms of hardness. I've never taken a countershaft out which wasn't worn enough to re-use.

Bronze thrust washers -If they are still thick enough to retain the cluster gear's tolerance in the case, Id keep, as some of the replacement washers are really steel, with a flash coating of copper on them, which will wear off in minutes, leaving steel to steel contact which will destroy the surface of the gear . You can test for a bogus 'bronze' washer by filing a bit of the edge of it. If you see bright steel showing through, it's no good. Filing a good one's edge will not in any way affect its ability to run properly.

As to the bushes in the cluster, some are pressed into it, others float on the shaft and are kept from moving with a steel tube in the centre.
You should feel the fit of the countershaft (new or used) in the cluster gear. Try to juggle it up or down to see if there is appreciable wear. The shaft shouldn't jiggle more than a thou or two. You can mike the shaft and cluster bushings if you have the gauges.

Definitely don't replace parts that look O.K. The manuals give you all sorts of specs to check, but really, if any part is worn enough to be replaced, it will show- the case hardening will be obviously rough.

That's my 2 cents' worth.
I would buy new bronze thrust washers but file the edge of them (not the thrust surface) to see if there is steel underneath. filing the edge a tad will not harm the washer's operation if it is a true bronze one and you use it.
"The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt"..Bertrand Russell

User avatar
17thAirborne
G-Lieutenant General
G-Lieutenant General
Posts: 5847
Joined: Mon Jun 21, 2004 5:42 am
Location: Central TN

Re: Opinions on Transmission Rebuild

Post by 17thAirborne » Wed Jul 08, 2020 3:55 pm

Bazza, excellent advice for me. Thank you.
Oz

Feb 43 GPW 98532 USA 20206257
Oct 70 Land Rover Series 2a 25334079G NZ16GF36
http://gpw.castraponere.com/ (My Restoration Page)

User avatar
1942 Ford GPW 352nd
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 286
Joined: Fri Mar 22, 2019 9:24 am
Location:

Re: Opinions on Transmission Rebuild

Post by 1942 Ford GPW 352nd » Thu Jul 09, 2020 4:40 am

Oz and all,
Thank you for posting this thread as I too am faced with the current dilemma after recently disassembling my T84. :D

donk_316
G-Major
G-Major
Posts: 941
Joined: Sat Sep 03, 2011 5:47 pm
Location: Edm, Canada

Re: Opinions on Transmission Rebuild

Post by donk_316 » Thu Jul 09, 2020 5:07 am

Heres a nice guide that doesnt include "..." every sentence and has pictures
http://www.42fordgpw.com/trouble-shooti ... nsmission/
GPW 112092 04-30-43 USA 20372531 (orig)

dinof
G-Major General
G-Major General
Posts: 2860
Joined: Fri Jan 08, 2010 4:32 pm
Location: Arcadia & Johannesburg Ca.

Re: Opinions on Transmission Rebuild

Post by dinof » Thu Jul 09, 2020 5:53 am

bazza46-Clear me up on the front thrust washer......Is it half steel, half bronze? I remember that one being part steel. I thought the side that sits up against the case being steel and the side that is up against the cluster is bronze.
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43
1928 Model A Roadster Pickup
1930 Model A Tudor
1968 Taco Minibike

User avatar
17thAirborne
G-Lieutenant General
G-Lieutenant General
Posts: 5847
Joined: Mon Jun 21, 2004 5:42 am
Location: Central TN

Re: Opinions on Transmission Rebuild

Post by 17thAirborne » Thu Jul 09, 2020 6:14 am

1942 Ford GPW 352nd wrote:
Thu Jul 09, 2020 4:40 am
Oz and all,
Thank you for posting this thread as I too am faced with the current dilemma after recently disassembling my T84. :D
You bet. Hoping we all get a bit more learned and wise.
Oz

Feb 43 GPW 98532 USA 20206257
Oct 70 Land Rover Series 2a 25334079G NZ16GF36
http://gpw.castraponere.com/ (My Restoration Page)

bazza46
G-Colonel
G-Colonel
Posts: 1550
Joined: Sat Aug 12, 2006 4:28 pm
Location: Sydney, Australia
Contact:

Re: Opinions on Transmission Rebuild

Post by bazza46 » Thu Jul 09, 2020 3:00 pm

Dino,
The large thin washer at the front of the box should be ALL bronze. That's the way they were originally. But in recent years, I have seen the steel backed ones you describe. I don't use them. I think it' a 'cheapie' design, as the washer is so thin already, there isn't potentially a thick enough layer of bronze that could be applied to it which would resist scoring, without wearing through to the steel. I've found them from time to time and I never use them.

The back of the case has two washers- the one against the case is steel, and is pinned so it doesn't rotate. The one next to it against the cluster is all bronze. Some new ones are steel, electroplated with bronze. Chuck them away.

I recently encountered a new one front thrust washer which looked O.K.- it was bronze coloured front, sides and back, but when I filed the edge, it was steel underneath, electroplated all over with a micro thin layer of bronze. I then scratched the running surface with a screwdriver, very lightly, and it exposed the steel. That one literally wouldn't have lasted a minute in service before starting to score the cluster. As the old one still held the cluster in spec, I reused it.

But it seems that it's all you can find, these days. I intend to buy a sheet of bronze bushing material and will cut new front washers from it if I can't find the original style ones.

Fortunately, I have one used but still in spec and unscored which I will use before I go that path.

Try filing the edge of your washer and then look to see how thin the bronze coating is. Use a fine file so the edge is smooth enough to see the layers.
I think that when they stamp out the washers, the edge gets dragged down by the die, which pulls the edge of the bronze coating over and makes it look thicker than it really is. When you file off that bit, you can see the true thickness (or thinness) of the layers.

BTW, there are many transfer case intermediate gear washers that are mainly steel with a coating of bronze about .008" on them. These are no good as that would wear off pretty quickly revealing the steel. The original were steel backed, but had a much thicker coating of bronze- at least 3/4 of the total thickness of the washer. I've even got a set I bought on Ebay that have the copper electroplated on them. It's too thin to measure!
"The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt"..Bertrand Russell

dinof
G-Major General
G-Major General
Posts: 2860
Joined: Fri Jan 08, 2010 4:32 pm
Location: Arcadia & Johannesburg Ca.

Re: Opinions on Transmission Rebuild

Post by dinof » Thu Jul 09, 2020 7:16 pm

bazza-Thank You for clearing all this up. It's very important info for all viewing this topic. This fits right in with rebuilding the trans the correct way.

You hit upon something that might of caused me some trouble with a transfer case that when you were driving, the two shift levers would shake and there was an audible noise. It might of been the shaft being too soft and causing vibration, but now when you mentioned that the bronze washers are used in the intermediate gear shaft, it could of been a cheap thrust washer that was always causing it as well.

Lesson for all here: Check out those "Bronze" thrust washers real good. You don't want to ruin a good cluster gear from this!
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43
1928 Model A Roadster Pickup
1930 Model A Tudor
1968 Taco Minibike

User avatar
17thAirborne
G-Lieutenant General
G-Lieutenant General
Posts: 5847
Joined: Mon Jun 21, 2004 5:42 am
Location: Central TN

Re: Opinions on Transmission Rebuild

Post by 17thAirborne » Fri Jul 10, 2020 5:32 am

I have been searching for these for a while. I found this site listing Bronze Transmission Thrust washers. I emailed him to ask if they are completely of bronze or just plated. WIll post answer when it arrives.

https://www.augum-parts.com/store/en/tr ... e-nos.html
432-001.jpg
Oz

Feb 43 GPW 98532 USA 20206257
Oct 70 Land Rover Series 2a 25334079G NZ16GF36
http://gpw.castraponere.com/ (My Restoration Page)


Post Reply

Return to “MB GPW Technical Knowledge Base”

Who is online

Users browsing this forum: No registered users and 19 guests