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

[wobson]

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

 

[SuperDuperCruizer]

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.

 

[BrendanT]

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?

 

[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?

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.

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

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.

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.

 

[wobson]

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.

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

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.

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

 

[BrendanT]

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.

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

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.

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]

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.

 

[BrendanT]

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.

 

[wobson]

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).

 

[Spook50]

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.

 

[wobson]

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.

 

[wobson]

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]

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]

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.

 

[jzilla]

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

Is all good? I now have an H55F apart and need a new countershaft.

 

[wobson]

Is all good? I now have an H55F apart and need a new countershaft.

I installed the box and everything seems to be fine.

Apologies for not reporting back sooner, I just wanted to get a few more kilometres on the box before I reported back, but the COVID restrictions and life in general have meant that I have not been able to drive it as much as I would like. As it stands there is about 500kms on the box and everything seems fine.

If your box is an older style like my one, and you need a new countershaft, you should be able to grab the newer style countershaft with a newer reverse idler and be good to go. Obviously do your research check the photos above etc.

All the best I hope it goes well!

 

[cruisermatt]

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.

i just re read my above comment and I must have been drunk or something when I wrote that. The reverse idler gear does move (back and forth on the reverse idler shaft).

 

[Spook50]

i just re read my above comment and I must have been drunk or something when I wrote that. The reverse idler gear does move (back and forth on the reverse idler shaft).

All's I knew was that reverse isn't synchronized. I suppose I'll lean a LOT more about these when I start getting parts together to rebuild hopefully next summer.

 

[jzilla]

I installed the box and everything seems to be fine.

Apologies for not reporting back sooner, I just wanted to get a few more kilometres on the box before I reported back, but the COVID restrictions and life in general have meant that I have not been able to drive it as much as I would like. As it stands there is about 500kms on the box and everything seems fine.

If your box is an older style like my one, and you need a new countershaft, you should be able to grab the newer style countershaft with a newer reverse idler and be good to go. Obviously do your research check the photos above etc.

All the best I hope it goes well!

Thanks! Yeah I am tearing into one for a customer though I am not sure the cost will be worth it.

 

[jzilla]

I installed the box and everything seems to be fine.

Apologies for not reporting back sooner, I just wanted to get a few more kilometres on the box before I reported back, but the COVID restrictions and life in general have meant that I have not been able to drive it as much as I would like. As it stands there is about 500kms on the box and everything seems fine.

If your box is an older style like my one, and you need a new countershaft, you should be able to grab the newer style countershaft with a newer reverse idler and be good to go. Obviously do your research check the photos above etc.

All the best I hope it goes well!

Do you have the part numbers handy? Remember what you paid?