Newby here 1973 J4000

[JustCreepn]

I can’t find squat online for parts on my 73 J4000 pickup with AMC 360. Right now I’m just trying to find a replacement alternator and having trouble with that. Every auto part website doesn’t even list the truck and the running the vin is useless cause it’s prior to 1981 and less than 17 characters. So can somebody point me in the right direction? Ppl on tv restore anything and everything so why is it so difficult.

[Rod2]

Have you tried Rock Auto? I've had some success there, and also BJ's Off Road.

[lkmarsh]

Most of the shows on the Motor Trend channel aren't doing restorations, and those that do
are very picky about which cars they restore, and this is why. Not every car and truck has
aftermarket support based on make, model and VIN. Forget the chain stores until you can
go in there with a part number in hand. I would suggest taking your alternator to a shop that
specializes in automotive electric work, have them test it and rebuild it if necessary.
Better yet, upgrade to a newer model alt with more amperage to cover all the goodies
you might install later.

[PossumJr]

Any 360 used in a jeep in 1973 had the same style Motorola alternator. I'll guess 55 amp but I don't actually know. There are a decent selection of aftermarket alternators to replace it and some remans available as well I'm sure.

[rocklaurence]

Have them search via a '73 Wagoneer with 360. Often, they have listings for the Wagons

[mjdriver]

On Rock Auto try searching for "J2500" , J3500 etc.. with the 360. Same at the parts stores they list them like that also. Might want to replace the voltage regulator aswell.

Sent from my moto e5 cruise using Tapatalk

[JustCreepn]

thanks for everyone’s input. Took the alternator into auto zone and guy laughed and said good luck. I mean come on something as simple as an alternator smh. But I think I’ve found a 100 amp on summit that will fit. The one I have is also 100amp it’s not factory sooooo I know there out there. I can’t really ask my grandpa anymore so it’s just a simple challenge. The main thing is the body work I want done to it anyways.

[Phils67]

Remy PN# 20172

[tgreese]

That Remy number looks right. It's a Motorola alternator. An automotive electrical shop could certainly help you, but I think there are plenty of more common resources that you are not utilizing.

There is a factory parts book that covers a '73 J4000 at www.oljeep.com - usually you can cross the factory part numbers of common service parts to aftermarket parts. Also get the TSM for your Jeep, so you know more about what you need.

The Autozone guys will be clueless, as you found. Try to find an old fashioned parts store, with old guys behind the counter and paper catalogs stashed away. Bond with them - chat in off hours, and they will help you. Parts counter work is boring most of the time, and helping you will be interesting.

Note that Jeeps are oddballs - comparatively few of them were sold, and you won't find the same aftermarket support that you will for Fords and Chevies. You'll need to be a little more resourceful, and realize that everything but typical service parts will be unavailable new (alternators are a common service part). I'd also suggest you cultivate sources for used replacement parts, such as the Jeep junkyards and part-outs by private parties.

[tgreese]

Also do not use the 100A alterntor to replace the 35A factory alternator without disabling/removing the factory ammeter. Otherwise you will likely have a dash fire somewhere down the road.

https://www.rockauto.com/en/moreinfo.ph ... 37&jsn=387

[Crankyolman]

When I decided to replace my '72 30 Amp Motorola I went with a 150 amp powermaster Jeep upgrade alternator because the Motorola can't handle EFI, they are on page 108-109 in their catalogue.
http://www.powermastermotorsports.com/catalog.html

[Phils67]

Rockauto lists it

[Crankyolman]

Every auto part website doesn’t even list the truck

I'm speculating that you are looking for a J4000 on the auto parts websites rather than a J4500, 4600, 4700 or 4800. The badging is the series, the 500, 600, 700 etc is about GVW. Rock auto lists them under the actual model, Autozone just lumps them all into J series pickup. My local autozone gives 3 options for your truck one of which is in stock, they all seem to be 37 amp. Since you say yours is 100 amp that means it has been changed at some point so normal auto parts places aren't going to help you. It's entirely possible the mount has been changed to accept the Delco alternator with the 2 inch wide mount or a Delco alternator mount has been cut down to fit the 1 inch wide Motorola mount. If you still have the 1" wide motorola mount you want a "Motorola replacement" alternator.

[tgreese]

Every auto part website doesn’t even list the truck

I'm speculating that you are looking for a J4000 on the auto parts websites rather than a J4500, 4600, 4700 or 4800. The badging is the series, the 500, 600, 700 etc is about GVW. ...

Yes, this info is in the introductory "identification" section of your TSM. Look at the build code in the VIN to determine the GVWR, then match that GVWR to the 4500, 4600 etc.

Jargon, but important jargon for a parts search.

[JustCreepn]

Ok so I took the alternator to a shop and he’s going to build me a 65 amp. As soon as I walked in he saw what I had and told me what he could do for me. The number in my door jam is J3A481ZN54932. Once again thanks for everyone’s input

[Crankyolman]

I'm glad you got the alternator figured out.

The number in my door jam is J3A481ZN54932. Once again thanks for everyone’s input

If you don't already know, the way that beaks down is J=Jeep, 3= 1973, A=Made in Toledo, TH400 transmission, Left Hand drive, 48=132" wheel base truck, 1=thriftside bed, Z= 8,000 GVW (making your truck a J4800), N=360 CID engine, 54932= serial number. ( https://www.allpar.com/mopar/jeep-vin.html )

If that is all correct when you are looking for parts you should be looking for parts for a J4800, although everything except the rear axle, springs and brakes should be the same as a J4600 or 4700, sometimes you have to enter a different but similar model to get what you are after. I think that also means you should have 8 lug wheels and full floating read axles. Of course a lot of stuff tends to get replaced and swapped out over the years on old trucks so you never really know until you start digging.

[JustCreepn]

Thanks Crankyolman I did not know that was the break down of my number. I’ve put it in multiple sites and got no results. Thanks for all the info it will definitely help me look in the right direction. As far as the alternator goes was there shims to align it straight with the belt? The bracket it’s on is not beefy enough to keep it straight when I tighten the belt. It works for now but isn’t right. When I took it off a half cut washer fell out but I don’t know from where or if any other fell off. But my pops told he from day one it was always like that and my grandpa had to shim it straight.

[Crankyolman]

Thanks Crankyolman I did not know that was the break down of my number. I’ve put it in multiple sites and got no results. Thanks for all the info it will definitely help me look in the right direction. As far as the alternator goes was there shims to align it straight with the belt? The bracket it’s on is not beefy enough to keep it straight when I tighten the belt. It works for now but isn’t right. When I took it off a half cut washer fell out but I don’t know from where or if any other fell off. But my pops told he from day one it was always like that and my grandpa had to shim it straight.

Your welcome.

The original alternator bracket is made up of 3 parts


They mount the alternator low and really close to the oil filter. #1 in the picture is the main big C shaped bracket. it mounts so the 1 inch wide pivot mount is on top, the sliding mount is on the bottom. #2 is sort of S shaped and mounts at the back side of the pivot mount and to a tapped hole in the passenger side cylinder head. #3 mounts underneath and if I recall right it uses the large long bolts that go through the water pump and bolts to the bottom of #1. If you need a picture of it I'll try to get one if the weather clears, right now it's raining and since I'm just getting over the flu I can't take one at the moment.

[JustCreepn]

yes it is definitely close to the oil filter. From your pictures I’m missing part #2 so I’ll make one and fit it up properly. Thanks again for your help and knowledge. Hope you recover 100% from the flu

[JustCreepn]

Can’t believe it’s been almost a year since I started this post. Well long story short the alternator is in lol. Only took a year I literally shimmed it up and reinstalled last weekend. Ordered a new rebuild kit for carb so waiting on that item. Anyways hope everyone is doing good.