Early vs late H55F lay (or counter) shaft (1 Viewer)

Joined
Sep 26, 2020
Messages
11
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Australia
Hi

I am doing up my early H55F gearbox (built 6/1985) and would like to replace the lay (or counter) shaft.

According to my research my gearbox is an early pre oct 1985 box and requires the early type lay shaft (33421-36040). Problem is I cannot seem to source one, I have called a number of reputable places here in Australia and they tell me that these old type shafts are not manufactured anymore.

I have heard anecdotal stories of people putting the later lay shaft (33421-60060) in the early box.

My question is, what is the difference between the early shaft (33421-36040) and the later shaft (33421-60060)? Are they interchangeable? If they are not directly interchangeable can a later one be used if I change some other parts (I think the reverse idler gear and input shaft is different between early and late), or is there something fundamental that will mean this is not possible?

Any thoughts on any of these questions would be greatly appreciated. This is my first post on this fine forum, thank you for responses in advance.

Cheers wobson
 
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There was a thread recently about this. Someone was having problems with the transmission popping out of 5th gear. If I recall correctly, the part you’re referencing can up in that discussion.
 
Joined
Oct 16, 2019
Messages
3
Location
Australia
Hi

I am doing up my early H55F gearbox (built 6/1985) and would like to replace the lay (or counter) shaft.

According to my research my gearbox is an early pre oct 1985 box and requires the early type lay shaft (33421-36040). Problem is I cannot seem to source one, I have called a number of reputable places here in Australia and they tell me that these old type shafts are not manufactured anymore.

I have heard anecdotal stories of people putting the later lay shaft (33421-60060) in the early box.

My question is, what is the difference between the early shaft (33421-36040) and the later shaft (33421-60060)? Are they interchangeable? If they are not directly interchangeable can a later one be used if I change some other parts (I think the reverse idler gear and input shaft is different between early and late), or is there something fundamental that will mean this is not possible?

Any thoughts on any of these questions would be greatly appreciated. This is my first post on this fine forum, thank you for responses in advance.

Cheers wobson
Just going through this exact process now, my gearbox is a 9/1985 H55F. Did you find a solution, is the new part the same?
 
Joined
Sep 26, 2020
Messages
11
Location
Australia
Just going through this exact process now, my gearbox is a 9/1985 H55F. Did you find a solution, is the new part the same?

After much reading on the forums, and alot of help from All Four x 4 Spares here in Australia, I just decided to buy the new one (33421-60060).

The main difference from what I could see is that first gear on the layshaft has a chamfer. See below.
IMG_E0296.JPG
IMG_E0297.JPG

The main issue with this is that it clips the reverse idler gear when it is not engaged. See below.
IMG_E0304.JPG
IMG_E0302.JPG

The way I resolved this was to replace the reverse idler gear with the newer post Oct 1985 one. You can see that it has a chamfer on that side also.
IMG_0371.JPG

As far as how my rebuild is going, I have rebuilt my box with the above changes and it behaves well on the bench. I will put it in over the holidays.

Hope this helps.
 
Joined
Sep 26, 2020
Messages
11
Location
Australia
After much reading on the forums, and alot of help from All Four x 4 Spares here in Australia, I just decided to buy the new one (33421-60060).

The main difference from what I could see is that first gear on the layshaft has a chamfer. See below.
IMG_E0296.JPG
IMG_E0297.JPG

The main issue with this is that it clips the reverse idler gear when it is not engaged. See below.
IMG_E0304.JPG
IMG_E0302.JPG

The way I resolved this was to replace the reverse idler gear with the newer post Oct 1985 one. You can see that it has a chamfer on that side also.
IMG_0371.JPG

As far as how my rebuild is going, I have rebuilt my box with the above changes and it behaves well on the bench. I will put it in over the holidays.

Hope this helps.
Large images below



IMG_E0296.JPG


IMG_E0297.JPG


IMG_E0302.JPG


IMG_E0304.JPG


IMG_0371.JPG
 
Joined
Oct 16, 2019
Messages
3
Location
Australia
After much reading on the forums, and alot of help from All Four x 4 Spares here in Australia, I just decided to buy the new one (33421-60060).

The main difference from what I could see is that first gear on the layshaft has a chamfer. See below.
IMG_E0296.JPG
IMG_E0297.JPG

The main issue with this is that it clips the reverse idler gear when it is not engaged. See below.
IMG_E0304.JPG
IMG_E0302.JPG

The way I resolved this was to replace the reverse idler gear with the newer post Oct 1985 one. You can see that it has a chamfer on that side also.
IMG_0371.JPG

As far as how my rebuild is going, I have rebuilt my box with the above changes and it behaves well on the bench. I will put it in over the holidays.

Hope this helps.
That is awesome info, thank you. I'm in Australia too (WA). My box is for a 9/1985 BJ70. Got 2 x gearboxes in pieces with the mechanic and neither had a good countershaft. Have used All Four x 4 a few times, they're quite good. Be very keen to know how it goes once back in the car.
 

Spook50

Christmas 2020
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Spokane, WA
How were you able to find the year of your H55F? I had one I recently had swapped in but not sure its age other than it's got (at this point) about 12K miles on a professional rebuild.
 
Joined
Oct 16, 2019
Messages
3
Location
Australia
How were you able to find the year of your H55F? I had one I recently had swapped in but not sure its age other than it's got (at this point) about 12K miles on a professional rebuild.
Went off the compliance plate on the vehicle, rest of car is very original so fairly confident it is the original box. The updated cluster shaft is the only one available now so not many other options anyway unfortunately.
 
Joined
Sep 26, 2020
Messages
11
Location
Australia
The easiest way to tell if it is an early or late one, without pulling it all apart, is to check what input shaft bearing you have. Pull the cover off and if the bearing is sealed it is a later one (post Oct 1985), if it is not sealed, like below, it is an early one (pre Oct 1985).
B4691654-E2B0-4455-A8EC-C8B1F0ED4803.jpeg
 

Spook50

Christmas 2020
Joined
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Messages
6,081
Location
Spokane, WA
Went off the compliance plate on the vehicle, rest of car is very original so fairly confident it is the original box. The updated cluster shaft is the only one available now so not many other options anyway unfortunately.
Your reference to the chamfers on the gears makes me wonder if mine is a pre 10/85 tranny. It's nothing more than a slight annoyance, but often when I shift into reverse (which knowing that it isn't synchronized) it refuses to go all the way into gear, as if there's a hard stop, rather than a stop and then engagement that a chamfered non-synchronized gear should do. Like I said that itself is not an issue. I just release the clutch, re-engage and I can shift into reverse with no problem. Though if mine is in fact an early tranny, this tells me the 1st/3rd synchro (which has been giving me trouble) could possibly be the original part since they're considered reusable during a rebuild. Looks like it's time to collect some parts and do a little updating on my tranny next summer if time allows.
 
Joined
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Messages
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Location
Australia
How were you able to find the year of your H55F? I had one I recently had swapped in but not sure its age other than it's got (at this point) about 12K miles on a professional rebuild.
As far as the actual year goes, if you have/know about the vehicle it came out of, then you can do what BrendanT suggests (this is what I did). If you don't know about the vehicle but you still have the original transfer case attached then you can use the numbers on the transfer case to find the year and month (look at this website Cruiser Outfitters). If you don't have the transfer case then I am not too sure how to get the exact year, only if it is early or late.
I hope this helps.
 
Joined
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Messages
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Australia
That is awesome info, thank you. I'm in Australia too (WA). My box is for a 9/1985 BJ70. Got 2 x gearboxes in pieces with the mechanic and neither had a good countershaft. Have used All Four x 4 a few times, they're quite good. Be very keen to know how it goes once back in the car.
No dramas, happy to share my journey. Hopefully it is useful. Best of luck with your build also!

I will post back once mine is up and going :)
 

cruisermatt

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Your reference to the chamfers on the gears makes me wonder if mine is a pre 10/85 tranny. It's nothing more than a slight annoyance, but often when I shift into reverse (which knowing that it isn't synchronized) it refuses to go all the way into gear, as if there's a hard stop, rather than a stop and then engagement that a chamfered non-synchronized gear should do. Like I said that itself is not an issue. I just release the clutch, re-engage and I can shift into reverse with no problem. Though if mine is in fact an early tranny, this tells me the 1st/3rd synchro (which has been giving me trouble) could possibly be the original part since they're considered reusable during a rebuild. Looks like it's time to collect some parts and do a little updating on my tranny next summer if time allows.

that's not how manual transmission gear selecting works. the gears don't move, the selector grabs all the teeth next to the gear. the chamfer on the drive gear teeth is likely an update for heat reaction or something like along those lines
 

Spook50

Christmas 2020
Joined
Feb 16, 2005
Messages
6,081
Location
Spokane, WA
that's not how manual transmission gear selecting works. the gears don't move, the selector grabs all the teeth next to the gear. the chamfer on the drive gear teeth is likely an update for heat reaction or something like along those lines
Ahh, see, still learning. So that negates my reverse gear theory. Though if in fact my tranny is the early model, it would enforce my thought as to why (IF they are the original parts) my 1st/3rd synchro ring is wearing. Moreso anyway than if my tranny is a later model.
 

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