rephrased ?, 3.0 gears in 4.0 m5r1 transmission

[themaxx69]

Rebuilding my tranny, noticed 1st and 2nd gears have some wear and 3rd was seized to shaft and the part with all the "small teeth" broke off, and main shaft is worn in a few spots.

So, I found the main shaft, then I noticed the 4.0 comes with higher gears in 1st, 2nd & 3rd than the other engines with the same tranny. So, couldn't I put 1st 2nd & 3rd from a 3.0 on my shaft? And, would I also need the counter cluster gear? Is it that easy Seems a lot easier and cheaper than changing the axle from 3.73 to 4.10...for now.

4.0L 3.40 / 2.05 / 1.31 / 1.00 / 0.79
3.0L 3.72 / 2.20 / 1.50 / 1.00 / 0.79

 

[Fx4wannabe01]

There's a member by the name of PlumCrazy(I think) that did this swap and he's a member here. He said he noticed a difference.

 

[nate09]

he used the gears from one behind a 2.5, not sure if theres a difference between the 2.5 and 3.0. check out this build thread http://therangerstation.com/forums/showthread.php?t=55201&page=3

 

[AllanD]

where you'll notice the "wide ratio" gears most with a 4.0 is at the top of third gear on a steep hill or when heavily loaded OR when towing a trailer and you have to let the engine scream in 3rd because you cannot make it spin fast enough to keep the pm from dropping too low when you upshift to 4th.

Even not heavily loaded the 4.0 can get a little "Breathy" at the top of 3rd.

Don't mind me but I actually liked the close ratio (4.0 gearset) behind my 2.9 engine
because of the smaller 3-4 jump.

AD

 

[PlumCrazy]

M50D transmissions from a 2.3, 2.5, 3.0, and I believe 2.9 truck are all the lower 1st, 2nd and 3rd gear ratios. The 4.0 OHV and SOHC transmissions got the higher gears.

Here are the final crawl ratios for various combinations or transmission and R&P gearings.

(First/Second/Third all in low range,2.48:1)
34.41/20.35/13.88 (Hybrid M50D w/ 3.73 R&P) - This is the combo I have now
34.57/20.84/13.32 (Stock 4.0 M50D w/ 4.10 R&P)
37.82/22.37/15.25 (Hybrid M50D w/ 4.10 R&P) - This is where I will be soon
38.44/23.18/14.81 (Stock 4.0 M50D w/ 4.56 R&P)

Notice 3rd gear is actually lower with the hybrid trannies and higher R&P ratios than stock with lower R&P ratios.

Having the hybrid tranny will allow you to get a final crawl similar to a stock tranny and the next lower R&P ratio but allow you to keep the RPM's down at highway speeds. You also dont have to worry about correcting the speedo either, since all the regearing is before the speed sensor. Another plus about gearing down the tranny is you can get final crawl ratios similr to 4.56's with nothing but JY parts whick are cheaper than aftermarket gear ratio prices.lol