Topic: Input gear disassmbly

[tx_shooter]

I purchased a t-case that already had a Marlin 4.7 kit in it. The only problem was that it was a 23 spline and my 4Runner is a 21 spline. Is there a way to transfer over the input gear from the 23 spline shaft to my 21 spline shaft?

[BigMike]

Hello tx_shooter,

And to land!!

That's awesome that you got one of our t/cases, congratulations!! You are gonna love it! It is possible to swap out the input gear however the input is part of the low range reduction system and as a result you can only swap out inputs from the same ratios. In other words, your current 21-spline input is from the stock 2.28:1 reduction gear set while the 23-spline input you just picked up is from our 4.70:1 reduction gear set. They cannot be interchanged.

To make matters a little bit worse, we make two different 4.70:1 gear kits: One from 8600-series material (our XD gears) and another from 4300-series material (our Competition gears). Whenever you have two gears meshing with each other, it is absolutely critical that they both have the same material properties as well as annealing process so that they have highly similar hardness, durability, and tensile and yield strengths. Otherwise the gear that is harder and more durable will rapidly wear into and destroy the gear its meshing with.

So to answer your question: Yes, absolutely this is possible. But we need to find out what gear kit you have ... if it is our Competition gear kit or our XtremeDuty gear kit. Do you know anything about the history of the t/case? Do you know how old it is? Does it have our name with a serial number stamped on the front housing that says "Marlin Crawler 4.70:1 123" where 123 would be the serial number?

At any rate you are going to have to open it up to swap out the input. Take a look at our 4.70:1 Installer (link) to get an idea of how it all comes apart (if you haven't already done this before). Once you've got the gears exposed, replying to this thread with a couple pictures wouldn't be a bad idea either

Regards,
BigMike

[ryantowry_81]

also if this is for a rear case in a double case setup you might want to look at getting the 23 spline coupler and retaining the 23 spline input and it would be stronger.

[tx_shooter [OP]]

Hello tx_shooter,

And to land!!

That's awesome that you got one of our t/cases, congratulations!! You are gonna love it! It is possible to swap out the input gear however the input is part of the low range reduction system and as a result you can only swap out inputs from the same ratios. In other words, your current 21-spline input is from the stock 2.28:1 reduction gear set while the 23-spline input you just picked up is from our 4.70:1 reduction gear set. They cannot be interchanged.

To make matters a little bit worse, we make two different 4.70:1 gear kits: One from 8600-series material (our XD gears) and another from 4300-series material (our Competition gears). Whenever you have two gears meshing with each other, it is absolutely critical that they both have the same material properties as well as annealing process so that they have highly similar hardness, durability, and tensile and yield strengths. Otherwise the gear that is harder and more durable will rapidly wear into and destroy the gear its meshing with.

So to answer your question: Yes, absolutely this is possible. But we need to find out what gear kit you have ... if it is our Competition gear kit or our XtremeDuty gear kit. Do you know anything about the history of the t/case? Do you know how old it is? Does it have our name with a serial number stamped on the front housing that says "Marlin Crawler 4.70:1 123" where 123 would be the serial number?

At any rate you are going to have to open it up to swap out the input. Take a look at our 4.70:1 Installer (link) to get an idea of how it all comes apart (if you haven't already done this before). Once you've got the gears exposed, replying to this thread with a couple pictures wouldn't be a bad idea either

Regards,
BigMike

I have it in parts on my workbench. I will contact the previous owner for more information about the gears. I do not believe it is a Marlin built case though. I will update with pics within an hour.

Thanks!

Updated: Pics

To rephrase the original question - can I move the new gear from the 23 spline shaft to the 21 spline shaft to keep the gear ratio correct? Is this possible or are the gear and shaft all one solid machined piece?

Oh yeah; I have worked myself into a time crunch hoping to have my transfer case back together before the end of the month so I can go to Texas Toyota Jambo.


Other pics removed because I found the Marlin serial. It is amazing what was hiding under some mud/grease.

[tx_shooter [OP]]

also if this is for a rear case in a double case setup you might want to look at getting the 23 spline coupler and retaining the 23 spline input and it would be stronger.

Good Lord I wish it was part of a double case setup. I even thought about buying an adapter just to "work my way out of this" but the bank account laughed at me.

[tx_shooter [OP]]

Bump for updated pics and info.

[boomtacoma01]

Bump for an answer for my old T-Case


Sent from my iPhone using Tapatalk

[BigMike]

Thank you for this picture. If the gears inside are the originals from this case, then WOW you have an early non-Total-Spline set, sometime from 1996 to 1998. I even checked our Official Crawler # Registry, the 4th oldest post on this forum, but this serial number is not in the list. Bummer!

So now we have a serious problem. The gears that you have were made by Advance Adapter's old gear cutter (who has since passed away). They were made on old equipment and are a poor design because 1) they used a pressed together multi-piece shift hub design that were prone to falling apart, and 2) these hubs lacked a 2-degree taper to prevent the shift collar from wandering or "popping" out of gear. You can read more about the gear popping out issue here (reply #3). It is because of these old gears that the Heavy Duty Shift Springs came into existence (as a band-aid to remedy a bad shift hub design). You can learn more about our HD shift springs here which I strongly recommend for safety sake if you are to use these gears -- hopefully the case already has a driver's side HD shift spring installed. Since we did away with this old shift hub design on our 4.70 gears I believe in the fall of 1998, Heavy Duty Shift springs are but a novelty item.

The serious & bad news for you is that because these are our old gears based on an obsolete design, having been since redesigned by Marlin with vastly improved features and produced by Toyota's own gear cutter in Japan, they are not compatible with our modern day gear sets. You could purchase a new Total-Spline 21-spline 4.70:1 input from us and try it out ... but there is no guarantee as to how long your old idler gear will hold up... It's not something I would recommend doing. The only thing I'd recommend is to come up with a pre-1999 21-spline 4.70 input gear. I'll take a look in our trophy room tomorrow to see if we have any used two-piece inputs laying around that are in useable condition, but this is a very long shot bet.

To rephrase the original question - can I move the new gear from the 23 spline shaft to the 21 spline shaft to keep the gear ratio correct? Is this possible or are the gear and shaft all one solid machined piece?

Sorry but the input shaft is part of the input gear and the two are inseparable.

Here is an example picture of an "input gear", which contains the input (where the splines engage with a coupler) and the gear that meshes with the low range counter shaft. This picture is our Turbo Total-Spline 23-spline input (link) which you'll notice right away looks different than the input you have:



The input splines are indeed connected to the input gear.

As mentioned, I will take a look tomorrow to see if we happen to have a good used pre-1999 21-spline input laying around, but I really don't give this much of a chance. Short of this, here are your basic options:
1. Purchase a new, improved 21-spline MC gear set, sell the one you have to someone who needs a 23-spline set.
2. Purchase a 23-spline dual case adapter and build a dual case setup where you'd have your current transmission with it's 21-spline output coupler -> 21-spline Crawl Box input -> 23-spline Crawl Box Coupler -> 23-spline 4.70 Input, done! This is the method ryantowry_81 mentioned above, and is what I did with my own truck: I have a 21-spline output transmission but have converted my drive train downstream of my first Crawl Box to all 23-spline parts for maximum strength (see reply #807 here for more info).
3. Swap in a Turbo transmission (very hard to find and are very expensive), or a W59 Tacoma 5speed, or a V6 transmission, where the later two options would require also purchasing a Transmission-to-Transfer Case Adapter Kit (see here) which use a 23-spline conversion coupler designed for our 23-spline 4.70:1 input gears.

I wish I had better news for you Sir. I know you mentioned about dual cases being out of the budget for now... This might be a project you'll have to put on hold until you can come up with some extra fundage $ to make the 23-spline gear kit compatible with your truck. Of the negatives mentioned above regarding our old & original 4.70 design, I'd like to point out that the set you have is still around so you've obviously got a good set on your hands! It's a testimony to our products and would be really cool if you could put it to use! I happen to have MC08-R10 serial number #001 in my truck -- the World's very first Billet Aluminum Rotated Dual Case Adapter -- and I am extremely proud of my long lasting Marlin Crawler parts!

Regards,
BigMike

[BigMike]

Bump for an answer for my old T-Case

Ah!! boomtacoma01, are the original owner, and if so, do you remember what month and what year you purchased it? This would be so neat to know! We do have all the older serial numbers recorded in a book in Marlin's office, which would have your information and purchase date listed. Finding our relics still out in the wild like this is so neat. I love it!

Regards,
BigMike

[BigMike]

One last thing to note is that the "T" in the stamped Marlin Crawler Serial Number stands for Turbo, which denotes that that housing originally had a 23-spline gear set installed in it. So much as that is concerned, it's looking good to be the original matched set.

tx_shooter- Please post up some pictures of the gears themselves, thanks for sharing and good luck moving forward with your project!

Regards,
BigMike

[boomtacoma01]

Unfortunately, I didnt purchase the Transfer case. It was in my 85 when I purchased it. I need to look around and see if the receipt is sncluded in file that was passed along to me. It performed flawlessly when in my truck with no problems. Im unsure if it has the HD shift spring installed.

Quote from another forum

This.



Trying to put 4.7s in my transfer case. The donor case that had the 4.7s was a forward shift with a 23 spline input shaft. I tore down the case; harvested the needed parts and am trying to put them in my case. The problem is that the smaller input gear is on the 23 spline input shaft; I need it on my 21 spline input shaft. I have looked it over pretty closely and do not see how/where it would come apart. Google-fu came up pretty short also.

So - is it going to have to be a new shaft or is there a way to move the smaller gear from the 23 spline shaft to the 21 spline shaft?

[tx_shooter [OP]]

BigMike;

Thanks for the reply. I guess it is good to know the gears have proven their mettle over the years. I will get some better pics when I get home tonight. As for looking around in the trophy truck room; I would really appreciate it. If you cannot come up with a compatable input shaft I will probably put the original transfer case back together and wheel it as is until I can do something better (read that - double case setup like you outlined).  This isn't a stopping point; just a set back.

[boomtacoma01]

Hopefully Mike can find you one Zech. More than like the best option forward is to reassemble the 4.7 case and get a 23 spline dual adapter and go duals when the time comes.

[Wainiha]

BigMike did you say a W59 is a possible solution?  I'm not positive, I previously looked at Marlins website pictures for ID.   I'm pretty sure I have a W59. 

Tx  shooter you can have it for free.  Shipping, as usual, kills all good deals here.  It probably would going back to you as well.

I have no idea if shipping is more expensive than the cost of a used one there....But, there it is...free+shipping. 

[tx_shooter [OP]]

I had already planned on going dual cases next; this just helps push that plan a little closer to the front burner for me. I'm curious though- where are you located at, Wainiha? I have been known to get around.

[Wainiha]

^shoot, that's why I said shipping kills it.  I'm on Kauai   I'm sure you must have cheaper options.  I should've just shut my mouth.  The offer stands though

[tx_shooter [OP]]

I would hate to even guess what shipping from Kauai to Ft Worth would cost. It might be cheaper to just go duals. Darn the luck. 

[BigMike]

Hello guys,

Sorry for the late reply. I did indeed check our back shop for a used two-piece 21-spline 4.70:1 input and only found a broken one (input snapped off). Sorry tx_shooter but we don't have one to sell you. Also, I'm not sure too sure about credit on trading it in... I think you'd get more bang for your buck to sell it to someone who needs a 23-spline gear set in the first place...

Wainiha, the route of going with a W59 contains the following three issues and solutions:
1. Problem: The W59 bellhousing only fits a 2RZ-FE or 3RZ-FE engine. Solution: You can use any 1984-1995 non-Turbo 4cyl bellhousing (G- or W-series) which mates to the 1995-2004 W59. Now you'd have a 1995+ Tacoma/4Runner W59 installed behind a 20R/22R/22R-E/22R-TE.

2. Problem: The W59 uses a left-hand front output chain drive t/case. Solution: You must get our transmission to transfer case bolt pattern conversion kit which changes the bolt pattern to work with a right-hand front output gear drive t/case (link)

3. Problem: The W59 uses a 26-spline output which is not compatible with the gear drive t/case. Solution: Our conversion kit above includes a coupler (at top-center of our picture) that converts the 26-spline output to a 23-spline so that now you can place a gear drive t/case with a 23-spline input behind the Tacoma W59 transmission. Now we have a rather complicated (explained below) but do-able solution for tx_shooter.

Complications...
- This will add approximately 1/2" to your drivetrain so your crossmember mount may not bolt up (might require slotting) and you'd want to ensure your drivelines can still work with the 1/2" offset.
- Because both the W59 and anything installed down stream from our conversion adapter requires a top shift t/case, regardless of application the t/case shift handle will move rearward by at least 1/2" (if you currently have a top shift t/case) and up to 4.5" (if you currently have a forward shift t/case which will need to be converted to top shift). Worst case scenario would require hacking up part of your center console, if applicable.

So there are a few complications with this route. Alternatively, we have built custom W59/W56 hybrids that use W59 front parts with W56 rear parts (so you can directly install a gear drive t/case right into your 4cyl Tacoma without any special adapters or couplers) (we require the customer to supply both a W56 and a W59 transmission since core parts are needed from both transmissions) (if your W59 needed a rebuild anyway, then this works out in the end since a good used W56 core transmission costs less than our new bolt pattern conversion kit). However, as W56 rear parts are all 21-spline, you'd still end up with a 21-spline hybrid transmission, which doesn't help tx_shooter and would effectively "downgrade" Tacoma/4Runner setups to the weaker t/case input. However-however, we will build the hybrid using the W59 output shaft -- yes the incorrect 26-spline shaft -- and then sell only the coupler from our conversion kit to then convert the spline count at the back of the hybrid transmission to a 23-spline and BAM you've got yourself a bonafide 23-spline hybrid W-series transmission at the expense of two transmission cores and our conversion coupler

Options... Options... Options...!

Regards,
BigMike


edit: Wainiha, I forgot to add that the W59 is only used in 4cyl versions of the 1995-1998 T100s, 1995-2004 Tacomas, and 1996-2002 4Runners.

[Wainiha]

It was just an offer from an uneducated person Mike.  (Me).  I got the thing for free just to look inside my first transmission ever.

You always take the time to type out good, informative responses  .  Thank you for the tech.  Maybe somebody here needs a W59.