4-speed Preferences

This is for all of yall who have put in a 4-speed. I see that most people around here either go with the Ford t-18 or the sm465. I'm leaning towards the t18 but started wondering what made yall choose one over the other.

 

Sm465 here. Would have done the t18, but this one popped up on CL with adapter, freshly rebuilt, and pretty cheap.

 

To an AMC engine the Ford T-18 is the easiest and you can use factory parts for the major components. With the '76 and newer bellhousing it bolts right to the engine and you can use a Jeep or Scout T-18 to rob the output shaft and adapter to put in the Ford case. Might do a search as this has been covered ad nauseum.

 

SM420 here. When I got it I was looking for an SM465 but stumbled across it cheap and figured what the heck, I can live with a deeper 1st gear but if I’d have known then what I know now I’d have kept searching for an SM465.

 

Picked up my SM465 for $50.

 

why would want the 465 over the 420? i guess what i am asking is what have you learned about the 465 that made it better than the 420

 

The main problem I have with the SM420 is the huge bulge cast into the passenger side to house the counter shaft assembly. Because of that it limits the size of the transfer case front output u-joint, you actually have to grind some of the bulge away to clear the transfer case front output. That also eliminates the possibility of using a double carden front drive shaft, limits the ability to clock the transfer case up for ground clearance and means the transfer case has to be mounted away from the transmission so the entire driveline is longer, the SM465 has a 1” adaptor plate available while the shortest I found for the SM420 was 4” long, all because of that bulge cast into the passenger side.
Besides that its getting old and parts are getting harder to find.
On the plus side it has the deepest “granny gear” of any light duty truck transmission and they’re hell for stout. If you break one of those you’re doing something really wrong.

 

I have a Jeep T18 in mine, only because it was available for the right deal at the time.. As noted above the most convenient swap is the Ford T18..

 

Ok. Looks like it came down to availability for most. I've done plenty of research over it all, I bet I know almost as much about it as you can without actually having done it. I've just never really read about why anybody chose a particular one over another. Thanks guys

 

CJ t-18 out of 79. Great 1st gear and is a straight bolt in.

 

The NP435 is another great alternative. Connection to the engine side is as easy for AMC engines as the Ford T-18/T-19, but you'd need a conversion kit.

As Nick mentioned, you can do the T-18 with only junkyard parts. All the others require a conversion kit.

Lots of earlier discussion on this topic ... http://www.google.com/search?q=site...fficial&client=firefox-a&source=hp&channel=np

 

I think the decision is highly dependent on the engine to be used. As Nick noted, if AMC, the T18 is likely the best/cheapest choice. If GM power that has the standard GM bell pattern, the SM465. Not only does it not have the bulge in the case and the shorter adapter available, it is considerably more robust and certainly is easier to find parts for than the older SM420. Down side: weighs significantly more. If you do decide to go with a SM420, the 67-68 ribbed case versions are stronger and the 68 should also be tapped for a backup light switch.

 

The SM465 to AMC motor conversion is not that bad. I'm in the process of assembling it now. However, the 465 is more difficult to rebuild internally than a t-18. This makes the 465-d18/20 step of hte process more difficult. Its got GIANT bearings to press on/off on the shaft ends, and big, brittle bushings to press on to the main shaft for the gears. I ended up getting a trans shop to do the rebuild/ mainshaft replacement. I got to the point where I wasn't having fun anymore, and I was doing more harm than good trying to do it myself.

There are 2 options to mate a 465 to an AMC motor:
1) machine out a T-5 bell to accept the custom SM465 front retainer
2) buy the custom bell and retainer together.

I'm going with the T-5 bell, but in retrospect, I should have just gotten the custom bell

http://www.novak-adapt.com/knowledge/465_to_amc.htm


I picked the 465 for 2 reasons. It has a very short adapter to the D18/20, and I found a good deal on the trans, adapter, and rebuild kit on CL.

Trans swap selection really comes down to 50% compatibility and 50% availability.

 

My .02 Gotta echo what timgr said. I started with a T18 in my 75 20 years ago and a year later yanked it and put a 435 in. Slower 1st and 2nd gear, but same BH bolt pattern as the T18. While the T/C adapter is a little longer the trans itself is an inch shorter so that offsets the total length a bit. I always seemed to hit reverse a lot trying to hit third gear in the T18 whereas the 435's reverse is over and down. Back then I was looking to go as slow as I could with 3.73's. I only gained a slight amount of crawl ratio (47.8 to 50.6) but to me it was worth the effort. That was before there were lower transfer case gears.

FWIW,

Mike

 

I read that the later model t18 found in 80's Fords shift pattern went to far right and down. Can anybody confirm that?

 

Yes, though I'm not sure what year it changed.

Jeep changed too. My J20 goes down and right, and I believe Jeep changed in 1979. So Ford's changeover should be sometime in the same era.

The down and right pattern is a big improvement. Even experienced drivers will clip reverse occasionally on a 2-3 shift when reverse is up by 3rd.

 

I have a 79 ford T18, reverse is over and down.

 

I have an NP435 in mine with a 302. The 435 has the same issue as the SM420. Bulge on the side of the case requires a longer adapter and a little grinding for clearance. Love the low gear, but would pick a t-18 next time.