Topic: SM465

[JFortner5]

Is anybody running an SM465 in their Jeep?  I guess really any old granny truck transmission would work for what I wanted to ask. 

My main question is not about the low(1st) gear.  I'll refer to it has first gear here to just make it easier.  Ok, so first is 6.55, 2nd is 3.58, 3rd is 1.70, and 4th is direct 1:1.  I have seen some people list the 3rd gear ratio as 1.57.  I don't mind losing 5th, I am still able to use it, but it sucks.  I drive maybe 200 miles a month on the interstate.  I have a little job I do every other Saturday that is about 60 miles one way.  That is the only time I get on the interstate with my Jeep.  During my normal daily to work and back routine, I never use 5th gear.

Now that I have that out of the way I will ask what I really wanted to know from you guys that have this tranmission or a similar one.  Obviously I would be starting off in 2nd gear under normal driving conditions, how bad does the rpm drop suck going into 3rd?  That is my only real concern with this swap.  Im just afraid that when I take off and put it in 3rd its going to bog down really bad, especially when starting off on a hill. 

Any of your experiences with this would be great.  I have an SM465 that I got for free so it would be nice to put it to good use when my AX5 grenades. 

Joey

[aw12345]

All I can say is that a lot of the older UPS brown trucks use that trans and coupled to a 4.3 v6 it moves those trucks just fine. Most all the drivers that drive those trucks use 2, 3 and 4th gear only. It's a good and pretty tough trans. 

[JFortner5]

Good point.  My plan is to keep the 4.10's and 31's for now until they are completely worn, and then replace them with 32 or 33" tires.  I was thinking the increase in tire size should keep my rpm down a little when running 65-70mph.  I'd like to be around 3k rpm at that speed.

[neale_rs]

I don't have any experience with it behind a 2.5 4banger but it is a great tranny behind a 350 V8 in a pickup.

The MB/GPW (60 hp 4banger) had these ratios and did fine:  
2.94
1.94 (34% change)
1     (48% change)

The SM465
3.58  
1.7    (52% change)
1      (41% change)

AX5
3.93
2.33
1.45 (63% change from 1st)
1     (57% change from 2nd)

You could try shifting your AX5 from 1st to 3rd  and from 2nd to 4th to simulate a worst case scenario and see how it feels.  
I think you could get the SM465 to work by just reving it up a lot in second.  Bogging depends more on your speed when you shift rather than on the RPM drop (as long as the drop still leaves you in a good torque RPM).

[JFortner5]

I tried going from 1st to 3rd today and it kind of sucked.  But it is a bigger rpm drop than 2nd to 3rd is with the 465.  I guess it wouldn't be too bad, I'm usually in 4th now by about 35mph so I ought to be able to make it to that speed with 2nd and 3rd with a 465.  Plus I think the 6.55 first would be awesome. 

[sharpxmen]

the granny gear will be great but having virtually a 3 speed for the 4banger would mean a big price on how it will move around. hwy probably not so much (once you get up to speed) but city driving will suffer quite a bit - there's a reason they eventually put a 6 speed in the 4cyl Jeep to keep it close to the power band as much as possible.

[JFortner5]

Yeah thats what I am afraid of.  I wish the gearing was a little closer together.  The main reason I am considering it is because its a free transmission.  I'm still weighing my options.  Like I said in another post, my transmission is still shifting good, I just want to decide which route I am going to go and try to gather parts up to be ready when mine does go out.  I really hate to put another AX5 in the Jeep.

[neale_rs]

I also tried the first to third shifting yesterday.  It forces you to rev it quite a bit in first to avoid bogging.  Also, on the small streets, it pretty much forces you to stay in first.  It will work but the MPG will very likey come down noticeably.

[dwtaylorpdx]

I think ya need one of these...

http://www.texracing.com/t10.html

:)

Dave

[JFortner5]

Oh sure that would be perfect.  I was really thinking about a Bert or a Brinn 2 speed circle track transmission.

Seriously though after I took a drive on a road I sometimes travel, I think the old 4 speed might not be my best option.  I might look into the ax15 or nv3550 a little more. The 1 to 3 shift sucks on flat ground, I could only imagine trying to get this thing up to speed on a hill would be terrible.

[dwtaylorpdx]

Seriously there is a advanced adapter to dana 300 from a super T10, the Nascar T10's have a bunch of gear ratios and they come up for sale a lot in the 1500 dollar range, at least then you could pick the gear split..  There is a 5 and six speed version of the tranny as well so it could be cool, but maybe pricey... :)

Dave