sm 465 popping out of gear
 

Hi, just thought I would share this, I just installed a new crate engine in my truck, then went down and registered it,,,now for it's maiden voyage with the new engine, runs great!!!! but the 4 spd was popping out of third gear, I hadnt driven the truck since I put this sm465/205 in it, except down the road at my house but never getting on it......looked online and found Anaheim Gear has replacement third gears upgraded from the old,I guess this is a common problem with sm465's never had the problem with my other trucks ...got the gear and slider, ordered a bearing /synchro kit and gasket set and there is a sleeve that replaces some lock rings on the intermediate shaft....anyway, I got it all back together and in the truck and SUCCESS!!!!!!! shifts perfect and stays in all gears like it should....I have a press and made a couple specialty tools from pieces of pipe and made my own socket to tighten the rear main shaft nut and used a bearing remover with a gear puller to remove the bearings ,it was a big job but worth it....there is a great youtube video of a guy tearing apart his sm465 from a 4 wheel drive like mine, was helpful

Re: sm 465 popping out of gear
 

I have had the same problem on my SM465 in a '68 C/10 [292 L6, 3.73 posi rear.]
I keep my hand on the shift knob if it starts to happen.

Don't get that gripe on my '71 GMC Jimmy [350,SM465,NP205,3.73 posi].

Wonder what causes it?

Re: sm 465 popping out of gear
 

I have not heard of this problem before, and don't have it with mine, but I am curious as to what you find out.

Re: sm 465 popping out of gear
 

I have heard of this before, seen some info online on how to fix, glad you were able to have success. I have this transmission in my truck but seeing as I have yet to drive it there hasn't been any problems.

Re: sm 465 popping out of gear
 

I have had this problem on nearly every truck with a 4 speed in it. It's because the gearing is such that the truck spends most of it's life in 3rd gear. Towing, starting, stopping, etc is mostly in 3rd. Most folks only downshift from 4th to 3rd, and rarely to 2nd due to the granny low.

It has to do with bearing and gear wear and there is just enough that it allows misalignment.

I am fearing this EXACT same scenario on my son's 70 GMC K2500 that we're doing. Dropping in a crate engine to a worn transmission/transfer case.

I hope that's not the case, but if I was a betting man.........

Re: sm 465 popping out of gear
 

This is a common problem. The transmission shop I use tells me its because people usually rest their hand on the shifter and are slightly pulling on it before upshifting. Time for a rebuild.

Re: sm 465 popping out of gear
 

Mine started slipping even after a rebuild.

Re: sm 465 popping out of gear
 

I have not had this problem with the other sm465's in my other trucks...I probably have over 200,000 miles on the one in my 74 K20 and never a problem,,,Bilt4me, they are not hard to rebuild, just a pain in the a#s to pull and put back in....especially mine with the transfer case behind it....don't be afraid to rebuild it yourself if you have a press.....

Re: sm 465 popping out of gear
 

Jim-
Wow, you're quick. You got that engine in and running, then pulled and redid the tranny in a heartbeat. Nice work!

I hope to get my "crate" installed this weekend. Got any tips for wrestling in the SM465 back in when the time comes?

Re: sm 465 popping out of gear
 

You start typing "SM465 pops" and Google shows top searches which finishes up "out of 3rd gear". One common suggestions is:

"There are two snaprings, they retain the input countergear and the third gear countergear. They wear and allow the two to walk, which causes the transmission to jump out of gear. These are replaced with a spacer bushing (p/n 14020811 from Anaheim Gear, essentially tubing as far as I can tell) like this.

But visit the Google and you will find a dozen threads addressing this.

Re: sm 465 popping out of gear
 

Great info Mike! Thanks!

What do y'all think: We currently have the engine out of the truck. Driveshafts are off. Transmission and transfer case are still in the truck.

Should we drop the transmission and TCase NOW and go through them for seals, the 3rd gear issue, seals and bearing? We have no idea if the trans /Case leak, make noise, are worn, or anything.

Should we pull them out and go through them or finish dropping in the engine and DS, get it up and going and see how it goes from there?

The SM465 and NP205 are the only pieces of the driveline that have NOT been rebuilt at this time. Rear axle had spiders blown out and center pin welded in, front axle had totally shot front knuckles and pinion leaks. Rebuilt both.

What say Y'all?

Re: sm 465 popping out of gear
 

Pay the man now or pay the man later... I would do it now. While you are still working on it and not down the road when all is finished and you want to drive.

Re: sm 465 popping out of gear
 

My SM420 had the same problem, I bought some NOS parts and had it rebuilt... Not cheap.

Re: sm 465 popping out of gear
 

I installed the spacer also on mine, even though my snap rings were still in good shape,no instructions came with the spacer, I looked it up online, you remove the two snap rings and a spacer on the intermediate shaft and install the spacer, figured I may as well fix it right, but the third gear and slider should be replaced as well, it is an upgraded gear ,I talked to a guy at Anaheim gear and ordered the gear and spacer over the phone....was about $160.00 for the parts, he also sent replacement springs for the shift forks...but I didnt replace mine, the detents were really tight ...I ordered a bearing and synchro/gasket kit off of Amazon for about $100.00...I did the work myself and pretty cheap vs. taking it to a trans shop...

Re: sm 465 popping out of gear
 

yeah buddy, it helps that I'm retired.....have time now!...pulling the trans/transcase was fairly easy, I have a transmission jack...pulled them as a unit, I installed the 465 by itself then the 205 w/adapter after that ...and ended up having my son help me align the transcase/crossmember ,just couldnt get it by myself...just wish I knew trans was bad when I had the engine out!!!let us know when you get yours running!!!my engine runs great, real happy with it..have less than 50 miles on it so far though..

Re: sm 465 popping out of gear
 

my brother in law has a sm420 in his jeep, it is popping out of second gear occasionally, any ideas? bad second gear?

Re: sm 465 popping out of gear
 

I think I would try and run them like they are, chances are they are fine....but if you can afford it , go ahead and rebuild the trans...atleast

Re: sm 465 popping out of gear
 

Call this guy, he knows everything there is to know about all these transmissions. He has an add on CL but he has an actual shop packed full of parts https://pittsburgh.craigslist.org/pts/6099317167.html You can also contact Novaks https://www.novak-adapt.com/catalog/...s/sm420-parts/ but they couldn't help me, they said the parts I needed are impossible to find but that guy on CL had them but he knew what he had... Nate

Re: sm 465 popping out of gear
 

thanks a bunch!

Re: sm 465 popping out of gear
 

Well, we made the decision to pull both the transmission and transfer case and have them rebuilt.

We COULD rebuild them ourselves, but we have too many other irons in the fire right now.

What pushed us over the edge was that I was under the truck and discovered that the transfer case rear output shaft bearing case was leaking and there was no oil in the unit. Also, after looking at how blown-out the rear differential was on this truck, ALL that same wear and tear has gone through the trans and T-Case.

Since the popping out of gear thing is SOOO annoying and leaks are also annoying, we decided to do it. The engine is out, the DS are off, there is no exhaust in the way.....It will take us less than half the time to do it now as to do it later.

I dropped them as a unit last night by myself in the driveway in 2-1/2 hours and I'm slow. I didn't realize that together, they are at least 500 lb. So, that was a bit of a challenge laying on my back trying to push around something that weighs more than I do. I didn't use a transmission jack, but a floor jack and some ratchet straps across the frame, and I still have all my fingers.......

Going back in should also only be a couple hours since we can go straight up and not have to worry about the tunnel and the interior.

I'm estimating about $1100 to have the two rebuilt including labor and parts (total for both)

Also, we found a shop in Topeka, KS that does LOTS of rebuilds and customs in 4x4's and prices are reasonable.

4x4Land.com

Mike let us look around for about 2 hours one Saturday in ONE of his 4 warehouses. He has NP205's and complete axle assemblies stacked on pallets and racks covering the walls and shelves. I was very impressed. Jeeps are his bread and butter, but his personal vehicles have been the 67-72 Chevy's.

Re: sm 465 popping out of gear
 

Was this the video?
https://www.youtube.com/watch?v=0wMUZ-m4f6w
I thought it was pretty good, too.

Re: sm 465 popping out of gear
 

good call, you will be glad you had them rebuilt,glad you could afford it , will save you alot of work if you had to pull them later... I just dont have the money to have them done at a shop...

Re: sm 465 popping out of gear
 

Great video.

Re: sm 465 popping out of gear
 

yes that is the one....

Re: sm 465 popping out of gear
 

Thanks Matt! It was your posting of this video that reminded me what it takes to rebuild these. When I lived on the farm, I had access to the presses, torches, space, and all that.

Now that I'm a city dweller (for 22 years) I only have a 2 car garage and driveway to accomplish this task.

I rebuilt a SM465 30 years ago, but forgot how much work it was and I was in my 20's then. Not as easy now as it was then!

We will have an all-new driveline when we're done. That will help with long-term reliability.

Thanks guys!