[Dougal]

Some gearboxes and ratios used with Isuzu 4cyl B series motors. To my knowledge all are cable change.

MSA series has existed since at least 1985, it is the heavier duty gearbox to be fitted to the 4BE1 and 4BD1 engines. Case and bellhousings are steel. Gear access is through the top aluminium cover.

MXA series appears to be the modern replacement for the MSA boxes, housings are lighter aluminium, they bolt up to the newer Isuzu 4cyl engines but can be made to fit a 4BD1.

MSB series gearboxes are lighter duty, used on th 4BC2 (3.3L) and 4JB1T (2.8 turbo) engines. Significantly more compact, gear access is through a side panel.

Other gearboxes and their ratios are included for interest.

MSA-5D
1st - 5.670
2nd - 3.415
3rd - 1.900
4th - 1.331
5th - 1.000
R - 5.680

MSA-5G,
5.788:1
2.998:1
1.594:1
1.000:1
0.776:1
5.798:1

MSA-5P,
5.788:1
2.998:1
1.735:1
1.000:1
0.776:1
5.798:1

MSA-5R,
4.987:1
2.998:1
1.594:1
1.000:1
0.728:1
4.774:1

MXA-5R
4.987:1
2.870:1
1.594:1
1.000:1
0.728:1


Isuzu MBP-6P
1st 6.378:1
2nd 3.627:1
3rd 2.239:1
4th 1.452:1
5th 1.000:1
6th 0.787:1
rev 6.595:1

MYY-6P
5.979:1
3.434:1
1.862:1
1.297:1
1.000:1
0.774:1
5.701:1

MYY-5P
5.315:1
3.053:1
1.655:1
1.000:1
0.721:1
5.068:1

Isuzu Mzz-6U
1st- 6.369
2nd- 3.767
3rd- 2.234
4th- 1.442
5th- 1.000
6th- 0.782
rev- 6.369

The mbp-6p is:
1st 6.378:1
2nd 3.627:1
3rd 2.239:1
4th 1.452:1
5th 1.000:1
6th 0.787:1


Model MSB-5S
Specification Matching Engine: 4JB1
Ratio:
1: 5.016
2: 2.672
3: 1.585
4: 1.000
5: 0.770
Rev: 4.783
Central Distance: 88
Torque: 230Nm


4JB1 fitted with MSB-5S
4BE1T fitted with MSB-5M
4BC2 fitted with MSB-5S (truck at home)
4HF1 fitted with MSA-5R (wymer brothers)
NHR (poss 4JB1) with MSC-5
MSA-5D and MXA-5D appear functionally identical

 

[dieselcruiserhead]

wow killer info.. We have a MSA of some sort in good used condition if anyone is interested.. Complete with bellhousing, $500...

 

[briney]

dougal, i have been looking a bit at jap truck transmissions lately. some have a removable piece where the shifter linkage comes off. the bulk of the main lid stays on. if the shift forks were under there, could you adapt something like a hilux gearstick and housing to work ? i might have to start whipping the lids off to see.

 

[Dougal]

dougal, i have been looking a bit at jap truck transmissions lately. some have a removable piece where the shifter linkage comes off. the bulk of the main lid stays on. if the shift forks were under there, could you adapt something like a hilux gearstick and housing to work ? i might have to start whipping the lids off to see.

Here's a picture of my (dirty) MSA-5G. The top cover is aluminum and comes off in one piece. It contains the shift rods and forks.

 

[briney]

i was looking at a daihatsu i think. it had a piece that came off that just held the rods for the linkage setup, and the forks stayed in the rest of the lid.

 

[averagef250]

I don't see why you couldn't rig a stick setup with some rods to run that.

 

[Dougal]

I don't see why you couldn't rig a stick setup with some rods to run that.

That's what Isuzu did.
Earlier trucks were linkage, later were cable change.

One of the guys on outerlimits has a bushranger (rangerover based kit car) with a 4BD1T and MXA-6R box in it (he supplied some of the ratios in that list). He used a japanese car gear lever (cable driven) in that setup. Eventually I'll do that to my truck too.

 

[Dougal]

Another surprise.
The later MSA boxes are significantly lighter. Featuring aluminium bellhousings and shifter forks.

 

[iman901]

one of the MSA trannys with overdrive would be perfect for my Ford swap. They're probably lighter than the NV4500 I am looking at, I dont know if they are availible in the USA though.

 

[dodgedougak]

Do you still have that MSA tranny?

 

[Dougal]

Do you still have that MSA tranny?

Who me?

That MSA-5G is now fitted to my vehicle, the MSA-5P that was in it is now residing on my garage floor instead. I need to use the 5P box to make up a linkage shifter arrangement as I plan to swap bodies to a later model with a different lever location in the near future.

The MSA box in my vehicle has the rear housing removed and an adapter plate fitted to mate up to the transfer box. I had a custom shaft made which fits on the external spline from the back of the MSA box into the internal spline on the transfer.

 

[(EST)MahviaDeTyrk]

How long are the Isuzu gearboxes ?

 

[Dougal]

How long are the Isuzu gearboxes ?

451mm from the bellhousing/engine face to the back of the main casing. There is an extra probably 125mm of back casing and transmission brake on there which I currently don't use.

 

[(EST)MahviaDeTyrk]

451mm from the bellhousing/engine face to the back of the main casing. There is an extra probably 125mm of back casing and transmission brake on there which I currently don't use.

Not too long
And nice slow first gears bounce
Any idea abouth weight ?

 

[Dougal]

Not too long
And nice slow first gears bounce
Any idea abouth weight ?

I can drag it around the floor myself, but I haven't lifted it.
Maybe around the 100kg mark. The earlier ones had steel bellhousings, the later are aluminium and significantly lighter.

 

[grandaddy-O]

I have an 87 Isuzu NPR roll back tow truck with MSA5D Transmission someone installed this trans which required some unknown modifications. Reading 4BT Swaps.com it looks like there was MSA5D, 5G, 5P, & 5R with the G,P, R being overdrive trannies. Does anyone know if the guts can be swapped between these units where as i can make mine into an overdrive. I also need a PTO for my MSA5D or any information about the PTOs. I also have a serious "knock" in my 4BDIT and will need to rebuild it. When I do ... what can be done to make more power and make it bullet proof? Any and all info will be most welcome!

 

[Dougal]

I have an 87 Isuzu NPR roll back tow truck with MSA5D Transmission someone installed this trans which required some unknown modifications. Reading 4BT Swaps.com it looks like there was MSA5D, 5G, 5P, & 5R with the G,P, R being overdrive trannies. Does anyone know if the guts can be swapped between these units where as i can make mine into an overdrive. I also need a PTO for my MSA5D or any information about the PTOs. I also have a serious "knock" in my 4BDIT and will need to rebuild it. When I do ... what can be done to make more power and make it bullet proof? Any and all info will be most welcome!

I think the guts could be swapped, externally they are identical. Of course buying the guts wouldn't be much different to buying a complete gearbox, you can leave the bellhousing behind to save shipping costs.
There is a reference section here: http://www.4btswaps.com/forum/showthread.php?3635-STICKY-Isuzu-4BD1T-4BD2T-Reference which includes all the power up threads. They are close to bulletproof as stock engines get already, do you know what caused your knock?

 

[terracon]

I have an 87 Isuzu NPR roll back tow truck with MSA5D Transmission someone installed this trans which required some unknown modifications. Reading 4BT Swaps.com it looks like there was MSA5D, 5G, 5P, & 5R with the G,P, R being overdrive trannies. Does anyone know if the guts can be swapped between these units where as i can make mine into an overdrive. I also need a PTO for my MSA5D or any information about the PTOs. I also have a serious "knock" in my 4BDIT and will need to rebuild it. When I do ... what can be done to make more power and make it bullet proof? Any and all info will be most welcome!

I put a Chelsea pto on my msa5d and the hydraulic shop mounted the pump right onto the pto, no shaft. It's a Parker pump. I originally bought the pto from another shop and I was going to use a shaft from the pto to the pump but the second shop said that was stupid and mounted the pump right onto the pto. Some slight grinding was necessary on the pump so it would clear a small bump out on the transmission but a die grinder took care of that. What's interesting is that if you look through the Isuzu parts catalogue there is a couple pages on the pto. It looks like when these trucks were introduced in North America Isuzu had a factory option for the pto. I guess no one made a pto for the truck so Isuzu made their own. I did make some inquiries some time ago and they do not support that pto anymore. But Chelsea does, that is why I went with Chelsea. If you want the model number I would have to look it up but Chelsea does list Isuzu MSA transmission in their pdf file. Find a dealer for Chelsea pto because once you get into hydraulics your head will start to hurt trying to figure out rpm flow rate etc etc. I love mine. I have a dump body on my truck and it works flawlessly.

 

[grandaddy-O]

Thanks for prompt replies ... shortly after Terracon's input I was able to locate at PTO connected directly to a pump coming off an Isuzu roll back with a MSA-5D trans. With any luck and a little hydraulic plumbing I will soon have my rollback bed, winch and stinger operational. Next up will be to tackle the knock in my engine which sounds really serious. I guess the first attempt will be to pull the pan and to see if all is connected and what is in the bottom of the pan. I think it would be wise to have an 1986/7 Isuzu shop manual prior to starting this project. Does anyone have recommendations as to which manual (exact name and number) and where from whom to purchase it? What about a parts manual? I've looked on-line but have had little results on finding a comprehensive repair manual that will give me details on pulling the engine, tearing it down for inspection & rebuild ... Again THANKS!

 

[bush65]

... I've looked on-line but have had little results on finding a comprehensive repair manual that will give me details on pulling the engine, tearing it down for inspection & rebuild ... Again THANKS!

Did you follow the links given in the 4BD1T/4BD2T Reference sticky thread on this forum? I seem to recall there were manuals there.