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Discovered a Transfer case swap!! DSD to PSD for Dmax

17K views 12 replies 9 participants last post by  handyandysperth 
#1 ·
So I received an email from a guy named Eric in Panama
He has a diesel Isuzu Dmax (edited) with a driver side drop front axle. I forget what year and model.
The engine he has is a 4jk1-tc is diesel 2.5 (or 4jj1 -tc is a 3.0 liter same has thailand and australia uses the same MUA5H transmission)
His is the one on the left, or right, I forget! LOL



His plans were to put a Nissan Patrol axle up front under it and do a SAS.
One problem though is that the Patrol front axle is PSD not driver side drop.
That's where his internet searches found me and the huge job I did to SAS my truck and the swap I did from the MUA5 to the Ar5 transmission.
He was very curious about the inputs and outputs of various cases and trans. Some we don't even have here in the USA.
So I helped as best I could.

As it turns out, the rest of the "new" Isuzu world some have these MUA5 transmissions that are DSD (not PSD like our MUA5 trans)
His is labelled MUA5H - there are more: MUA5S, MUX5S but I'm not familiar with those, nor did Eric fill me in on them....


Below are pics of the Mua5H output and the DSD trans he has.





Female input on Transfer Case he has:

Rear output with the Mua5H and the DSD case:


The output is a slip shaft style and not a flange. That is very different from ours!

front input and output of the 4wd on the DSD case


Even more amazing, is that the MUA5H does not have the integrated transfer case. :!: :eek: :shock:
It bolts onto the back.
The MUA5 we have in the states has the integrated case in the middle and last clams of the entire Transmission! :evil:

And even more amazing was when he sent me pictures of the rear output and the case female input, I told him to go find a V6 3.2 transfer case from an automatic trans Isuzu and see if it would fit. :idea:
He told me the spline count was 27 and the pitch was the same as what I measured out for the slip shafts on the GM 4L60's.
That is the same as the Mua5 I had and the Ar5 input! :shock: :mrgreen:
Now we're talking. Isuzu was smart enough to keep a good thing going and they did it for years and years.


This sounds really promising that a PSD case would fit his diesel Mua5H transmission. :albino:



So I mod'd a comparison photo: Ar5 output on the left and the Diesel Trans output on the right.
They look so similar!

I sent some rough measurements of the female input on the stick shift transfer case i have.

Getting closer now.....

So Eric pulls an electricly shifted transfer case from a V6 Isuzu in Panama and attempts to bolt it up to his Transmission......





Looks like a 4L30 automatic, anyone confirm from the pic?


Now check out the PSD (left) and the DSD (right) cases side by side:




Well buys and girls... drum roll please......

they line up.
Amazing!







Lastly the driveshaft flange lines up too!

another good thing Isuzu never stopped doing!

Not every single bolt hole lines up but that could be solved with a skinny adapter plate and you now have soooo many more options for front axles.
Now if we could get a hold of the DSD Isuzu cases here in America we would have the opposite options now available!
We could go hunt down the more readily available DSD front axles for our SAS jobs!

:bigsmurf:

I'm going to try to get Eric to join the board so he can share his adventure in Panama with his transfer case discovery.
 
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#2 ·
That's some really awesome information. Too bad Isuzu didn't offer a DSD case here in the states or maybe the MUA that had the transfer as a separate unit.
 
#3 ·
One last thing that is not clearly obvious, is now the newer Isuzu's with this transfer case swap can get regeared with what Revo gears Inde4x has left.
Eric was also trying to solve the same problem I had with low range options better than stock 2:1 without having to fabricate and modify a one off solution.
 
#4 ·
This is an amazing connection Lorenzo!

I wish my MUA had a removable case...

Get him on here, I want to see/read more.

cheers
-Ian :blackeye:
 
#6 ·
Since you've done an ar5 swap the main case on that transmission is that same as many other ones including the jeep ax15, I haven't looked into all the details but I'm sure you could swap in a t case from one of those and get the dsd. Though I'm not sure if the spline counts are the are same.
 
#7 ·
The devil is in the details.
That specific Aisin case has 3 different input shafts and lengths with different splines on two of them over the years. The bolt pattern on the front is same so you could tear down, replace input shaft to match your desired bellhousing.
The output case and shaft is different for each auto brand: GM, Toyota and Isuzu all have different bolt patterns and out put shafts.
Only the internal parts and the center case is the same. Gear ratios are a little different here and there... but anyhow.
The early R150 boxes have some improved synchros you can get through marlin crawlers but iirc those improved synchros are in production on all the modern aisin boxes because of what they learned in the 80's on the r150, r151 and r154.
I have talked with a few guys here who tore down the tacoma R151 or the turbo'd yota r150 to replace the input shaft to mate and use the 3.2/3.5 bellhousing to match so they could get a yota doubler in the back of the rear output.
all possible with $$$ and elbow grease.

But the MUA5H would be super cool to have here in the US.
We could explore some DSD options like a Ford high pinion!
 
#8 ·
hello isuser,s just signed couple mins ago im new here
i made a intro on other part of the forum but not sure since i dont know how to use it right now
yeah with the help of Lorenzo with some tecnical info about these transfer/transmision
ill post more info when i figure out how to upload picture from my android (wich program is better)

thanks in advance
 
#10 · (Edited)
Hi, I know this is an old thread.
I just want to say thank you, because the information on this thread has gave me courage to do a 4x2 to 4x4 swap for my 2016 MU'x.

Engine is the same 4JK1 2.5L with Eric's DMax but mine comes with Aisin TB50-LS 5-speed Auto Tranny or AW 750F in Toyota's word.

I've done research that Auto 4x4 DMax share the same DSD Transfer Case with the manual version, but with an adapter.
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I've bought the adapter and trying to install the Transfer Case couple weeks ago.
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Sadly I have to postponed the process, it turned out that the Auto Tranny had different output shaft splines with the MUA's. So now I'm in process of ordering the Transfer Case input shaft with matched spline (remarks number 1) from Isuzu. Hope it'll be a happy ending 😇
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Andy
From Indonesia
 
#12 ·
Check out the Australian Dmax models: 2008 - 2012 Isuzu Dmax transfer case has the drive shaft down the right hand side of the car (Australian drivers side), where as the 2012 - 2019 has it down the left hand side of the vehicle (Australian passenger side). Both cases are removable from the gearboxes. You should be able to find them listed on eBay or Australian Wreckers if they'll ship internationally.
 
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