muncie 4spd?

i have found a fella selling a muncie 4spd adapted to a dana 18.
what do you guys think? i know the gears are not good in the low ratio range, but could they be resold. any kind of a market for these things?

 

The sm420 is a great transmission for a CJ. Relatively short, a nice low granny, and very strong. It's the 4 speed I have in my CJ. That granny gear is low enough that I can start up the CJ in gear, on a steep incline, with my foot all the way to the floor on the brake and it will start right up and climb up the obstacle. Very convenient when you stall in an inconvenient spot.

Novak's page on the SM420
SM420

Novak's page on the SM465 that Patrick mentioned:
SM465

 

the sm-420 is a great trans. but isnt a fast shifter

i had one in my 2.5l tj

gerald

 

yes, im sorry theres only like 6 different trannys arent there.
its a side loaded m20,21 or 22. which of those im not sure...
its adapted to the dana 18. it has an od with it also.

 

Good for the dunes, and mud bogging I'd presume.

http://www.5speeds.com/muncie2.htm

Year 1963-1965 Type: M20 Rings: None Ratio: 2.56 / 1.91 / 1.48 / 1.00 / 3.16
Year 1966-1974 Type: M20 Rings: Two Ratio: 2.52 / 1.88 / 1.46 / 1.00 / 3.11
Year 1963-1974 Type: M21 Rings: One Ratio: 2.20 / 1.64 / 1.28 / 1.00 / 2.27
Year 1967-1974 Type: M22 Rings: None Ratio: 2.20 / 1.64 / 1.28 / 1.00 / 2.27

The Borg-Warner 3-speeds have a first gear ratio of about 3.0:1, so with any of these you'd have taller gears off the line. In a Jeep, with deep (high numeric) rear axle ratios, it's probably ok for daily driving. On the trail, you'd gain faster shifting and additional strength, but "worse" gearing (depending on the terrain).

 

A used Muncie will sell for around $200 if it is complete and not trashed-and a lot more if it happens to be the right number for a restoration project. The AA adapter kit is also worth a few bucks and fits all of them. The wide ratios will work behind a V8 resonably well off road if the engine is set up to deliver a bunch of low end torque. The wide ratio aftermarket AGE M22 I am using has the same low gear as the early 20's-2.56:1. Off road, I do not think I have ever turned more than about 2500 rpm using this trans. I had an M20 for years and spend most of a year deciding on the replacement. The AGE unit won because it is about as bullet proof as anything you can get and it weights about half of what a SM465 does. I would not run one of these behind a 6 and a set of Terra Lows is almost mandatory.

 

If you go look at it check the cluster gear shaft where it presses into the case. Common for M20's and M21's to wear the bore in the case and allow the cluster gear to move around and also leak right there. Not much call in my area for car tranny's adapted to Jeep transfer cases unless you find a dune runner or a racer who wants a manual trans. Most seem to go for auto's these days. There are those out there who want them, but you may have to be patient and sit on it awhile before it sells.

 

Just a heads up Chuck, that's a Saginaw 4 speed in your pic. Reverse is in the main case which is a giveaway on id. Muncie M series and BW T-10's have reverse in the tailhousing or adapter.

If you were closer I'd be interested in it.

 

If the price is good it might be worth it for the D18 and OD!

 

I have a M21 mated to a D18 and am not very happy with the setup. Doable on the trails and hills, but still way too tall gears, even with 488 gears and 33s. I have a SM420 in the corner of the garage waiting to go in once I have the adapter funds.

 

No it's not a bad set up. Judging by the witness marks on the input shaft that should be an even split transmission. Not the widest ratio, should be the second widest ratio available. I run a Saginaw in my '59 CJ-5 but it's the wide ratio. About a 3.5 or so to 1 first gear.

 

I bought mine with a close ratio muncie and AA, nicest shifting , if it was sold to a guy with a street jeep thats a great set-up. mine was an incomplete box of parts when I sold it for $50 to get rid of it , the pocket bearing was done and fused itself to the main shaft , I used a few tranny parts/sycros and gears in the 442 when I was draging that car........I went ford T-18

 

I have a 283/M21/D18 with 4.27 and 36" tires, its NOT a crawler and pretty sure that I'll have lot-o-problems getting it up on top of the snow.

Sand dunes on the to other hand, Ya Haw, if after 5min you don't blow the rear driveshaft out.

Street use, it's nice but only use 2 sometime 3 gears, it was worse with the 5.38s. Gears are so close with little drop that it's almost like a down shift when going to the next gear. This causes a problem in the fact more gas is required and then it's just time to start grabbing gears.

 

You'll love the SM420.
I wheeled the T-10 in my Jeep for a couple years, and burned the hell out of my clutch trying to do it, before making the switch.
The difference was night and day, or about 2.68:1 first for the T-10 vs. a 7.08:1 first for the SM420.

 

Ya there junk.you buy it and ill come take it off your hands.not much rock crawling around here but lots of dunes.

mike s.