Marks4WD Gears - 2.7 vs 3.15 in 5MT/Diesel

na3s

Active member
Looking for some insight, especially from those who have installed and run the Mark's gears, as to which ratio would be a better fit for my intended needs/usage.

Slowly building a D50 with a D4BF(4D56t) turbo diesel / V5MT1 5MT / 4.636 diffs / 235/85r16AT (+/-32") to be used primarily as an overland, dirtbike/firewood/logging road hauler, bad winter weather, and general go anywhere truck.

While rock crawling isn't typically on the menu, I'd like the increased security of a substantial low range crawl ratio to reduce the overall strain on the rest of the drivetrain/suspension/truck in tough situations, aid in navigating steep/rough/primitive roads/tracks in deep mud and snow, and in instances when the truck is heavily loaded.

I recently tracked down a V5MT1 w/Super Select transfer case from a '95 Gen 2 5MT and in addition to rebuilding the transmission, plan to order and fit Marks4WD gears, the question is do I go 2.7 or 3.15?

2.7 Gears (Gen 2/5MT) - https://www.marks4wd.com/paj-gen2-2-7m.html

3.15 Gears (Gen 2/5MT) - https://www.marks4wd.com/paj-gen2-3-15m.html



The general consensus seems to be that 3.15 gears are the way to go, but the vast majority of those who run them are into more significant crawling than I intend to undertake, and do so with 4ATs; Aisin R4AW3s (1st: 2.804, 2nd: 1.531, 3rd: 1.000, & 4th: 0.754).

Factoring for the same 4.636 diff gearing I'll be running, a 4AT would yield the following crawl ratios:

2.7 Gears = +/- 35:1 (2.804 * 4.636 * 2.7)
3.15 Gears = +/- 41:1 (2.804 * 4.636 * 3.15)



However, since I'm running a V5MT1 5MT, my 1st gear will be much lower (1st: 3.918, 2nd: 2.261, 3rd: 1.395, 4th: 1.00, & 5th: 0.829), resulting in the following crawl ratios:

2.7 Gears = +/- 49:1 (3.918 * 4.636 * 2.7)
3.15 Gears = +/- 57:1 (3.918 * 4.636 * 3.15)



While, I'm pretty confident the 4.636 diffs will fit my needs, there's a remote chance I may end up with 4.90 gears if I ever increased the tires to say a 285/75R16 (+/-33") at some point down the road, such a change would yield the following crawl ratios:

2.7 Gears = +/- 52:1 (3.918 * 4.9 * 2.7)
3.15 Gears = +/- 60:1 (3.918 * 4.9 * 3.15)



The 3.15 gears just seem too low and slow for anything I realistically intend to do, in light of that, I'm leaning heavily toward the 2.7 gears.

It seems they'll be more than adequate for my needs, particularly with the diesel's low end torque, and will require less modification to fit, avoiding many of the issues reported with installing the 3.15 gears in 5MT transfer cases:

Screen Shot 2020-08-05 at 11.54.41 PM.png


Can anyone more knowledgeable than myself think of anything I've missed, haven't considered, or offer any first hand experience?

Thanks!
 
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plh

Explorer
I don't remember specifically any more due to the multiple years past since researching. But IIRC the 2.7 and 3.15 TC gears are made for different cases.
 

billiebob

Well-known member
The 3.15 gears just seem too low and slow for anything I realistically intend to do, in light of that, I'm leaning heavily toward the 2.7 gears.
There ya go. Given what you say you do, I agree.
You missed nothing.
 

na3s

Active member
Bumping this up to ensure I'm not missing anything before finally pulling the trigger on the 2.7 gears, want to be sure I make the right call and don't end up regretting not ordering the 3.15 gears.

The more involved modifications, especially to the shift rail, potentially weakening it significantly, required to fit them to the 5MT transfer case are the primary issue dissuading me:

Screen Shot 2020-12-29 at 4.36.07 PM.png


I REALLY wish the images in this forum posting were still visible/hosted someplace:

Screen Shot 2020-12-29 at 5.25.38 PM.png


Although, the more I read, it seems that in a 2.5TD/5MT configuration the 2.7 gears are a great middle ground; with his axles he's also only at +/- 44:1 where I'd be at +/- 49:1:

Screen Shot 2020-12-29 at 3.41.29 PM.png

Screen Shot 2020-12-29 at 3.42.24 PM.png

Screen Shot 2020-12-29 at 3.43.45 PM.png


Thanks!
 
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na3s

Active member
I may have put the horse ahead of the cart...

The more I look into and cross reference part #s, the more and more convinced I am that the 2.85 gears Marks4WD claim are for a Gen 1 will actually fit the transfer case from the 5MT Gen 2(3.0/24v) I tracked down to gain Super Select(AWD).

The donor vehicle was a 5MT Gen 2(3.0/24v), VIN # JA4MR41H6SJ011630, which is shown to have the following transfer case gears:
'95 5MT.jpeg

Input GearMD731636
Low GearMR195444
Countershaft GearMD737109


With input gear MD731636 showing 24 splines:
Screen Shot 2020-12-29 at 8.04.45 PM.pngScreen Shot 2020-12-29 at 8.27.32 PM.png


This would indicate that the US Market 5MT Gen 2(3.0/24v) shares the same transfer case gears as the Gen 1s and MSs, as Edward(ES_97Sport) has posted:
Screen Shot 2020-12-29 at 8.45.55 PM.png
[/URL]


Further supported by this older 4x4wire thread: http://4x4wire.com/forums/ubbthreads.php/ubb/printthread/Board/20/main/37803/type/thread.html


This seems to align with the info on the Marks4WD site, indicating that the 5MT Gen 1 2.85 gears mate with a 24t input shaft, whereas they state the 5MT Gen 2 gears, both 2.7 & 3.15, mate with 27t input shafts:
Screen Shot 2020-12-29 at 9.21.33 PM.png

Screen Shot 2020-12-29 at 9.24.42 PM.png

Screen Shot 2020-12-29 at 9.25.59 PM.png


While I haven't torn down my 5MT Gen 2(3.0/24v) transfer case yet to verify, it's cold and my shop doesn't have heat, the 2.85 gears might be a perfect windfall, splitting the difference between the 2.7 and 3.15 gears, yet not necessitating as much modification to the case and shift shaft to fit:

[/URL]


With the V5MT1 5MT and 4.636 gears, they'd yield a crawl ratio of +/- 52:1, (3.918 * 4.636 * 2.85 = 51.7669668:1), which I think would fit my needs very nicely. A bit lower than the 2.7 gears while avoiding any concerns about durability from the weakened/modified shift shaft required to clear the 3.15 gears.

I'll update this thread as I discover more in hopes that some of this esoteric info may perhaps be of aid to someone undertaking a similar project in the future. It's been an ongoing hurdle to determine all of the subtle differences in part specs between seemingly similar models sold in different world markets.

As always, if anyone more experienced has any info, input, or advice, I'm all ears and appreciative, thanks.
 
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Toasty

Looking for that thing i just had in my hand...
I've owned all of the above ratios (plus others), personally i'd run the 3.15's with a manual because i don't like nursing a clutch on technical climbs especially carrying a load. However my friend just installed the 3.15's into his 5 spd Paj and the shop he hired had a hell of a time installing them, 2.72 or 2.85 would still be a game changer and you won't be dissapointed UNLESS you've experienced 3.15, 4:1 or 4.7:1. I say go for the 2.72 or 2.85 gears just for ease and still having a trail cruise speed in low range.
 

na3s

Active member
Thanks Toasty, it's great to hear from someone with first hand experience. I'm sure I speak for a great many on here when I say thanks for always being so open and generous with your vast knowledge about these trucks, reliable info is often hard to come by; your inputs are always super appreciated.

Based upon your advice, Edward's (S_97Sport) info, cross referencing and verifying part numbers, and separating my transfer case from the V5MT1 to confirm the output shaft is 24 splined, the decision was somewhat made for me by virtue of the fact that the 2.85 gears are the only option that will fit my configuration.

IMG_5882.jpg

That said, I think they'll fit my needs perfectly, giving me a crawl ratio of +/- 52:1 and avoiding much of the trouble associated with modifying the shift shaft to clear the 3.15 gears.

My project's been a slow burn, but these gears will be another solid piece of the puzzle in place!
 
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Toasty

Looking for that thing i just had in my hand...
Always hapy to help, don't give me too much credit i've spread some misinformation over the years as well. It's not uncommon for someone to do a thing and have it blow up in their face then come to me for answers.

Them - "I did what your post from 2005 said on 4x4wire!"

Me - "ooh, yeah i learned that was bad. sorry" 🤕
 
I just got some of the 2.7s for my manual 2.8td Pajero. I based my buying on the same things you have talked about. Also the 3.15s sound like a real head ache to get in. My gears should be installed by the end of the week. So fingers crossed i made the right descision too! To round out the picture I have 4.9 diff gears and run 33s. I'll give an update once I test drive them if you want.
 

na3s

Active member
South, I think you're right, the headaches associated with installing the 3.15 gears in a 5MT are a big deterrent. But it sounds like you'll end up with a solid combo with the 2.7/4.90/33s; please do keep us posted regarding both the install as well as the performance of the new gears.

Is your 2.8 a 4M40 or 4M41?

What 5MT transmission is it mated to, V5M31?

Does it have an alloy case w/integrated bell housing?
 
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Hi there, finally got offroad with the new gears. First test was down a riverbed so mostly fairly flat with moderate banks to climb up and down. The gearing is certainly much lower than what I had previously. First gear in most of the conditions today was unusable. Which is a good thing cause like I said it was mostly flat going. Did test it coming down a bit of a longer gradient and it held the vehicle at such a slow speed it was almost laughable. There was no extra noise from the transfer case and everything shifted as it did before. So all in all I would say I am quite happy so far.

I ended up not doing the install. I had my local shop do it. They had to modify the case slightly but once that was done they said the gears fit like a glove and everything fit back together easily. I ended up getting a new clutch and did the rear main seal on the motor since we were in there which are nice to have off the plate as well.

Oh and it is a 2.8 4m40 with a V5M31. It does not have the alloy case w/ integrated housing.

Happy to report more later if people care. We have a trip in 2 weeks into the mountains so I should probably be able to get a better feel for what my new low gear is really like.
 

na3s

Active member
Happy to hear the install went smoothly and the difference in handling and control is so noticeable and positive.

I'm still waiting on my gears and will more than likely end up installing them myself, along with full rebuilding my V5MT1.

Hope your trip to the mountains goes well, be sure to keep us updated, thanks!
 

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