Muncie question - Kicks out of 3rd gear

Hey guys, not necessarily a Mopar question but if it helps it's hooked to a Dana so maybe it can be asked here.. That being said, my father in law has a Muncie that kicks out of 3rd gear after about 4000 RPM. Doesn't matter how hard you try to hold the shifter, it'll kick out. He's swapped shifters, shift rods, shift levers and adjusted things multiple times with no real improvement. I've got a couple thoughts on what it may be but am not an expert by any means so I figured I would inquire here as to what the experts may think the problem may be. Hoping to get this resolved soon without sacrificing another 833 input shaft so I appreciate any help. Thanks guys!

For what it's worth, it does have a Supercase if that matters...

Has the bellhousing been indicated in to concentricity with the crankshaft? Have the engagement teeth on 3rd gear and the internal splines on the slider been checked for rounding/wear/damage? I'd start by pulling the side cover and inspecting the teeth, that's the easiest.

Well, he does have a Dana, but the Chevy forums or something like the Yellow Bullet are probably a much more effective place to find an answer about Muncie transmission tech, althouh there are some very knowlegable folks on this site, hence the bump.

A transmission is a transmission. If you understand an 833, you understand a Muncie.

You may be on to something with the bellhousing. Years ago when we assembled the car, I dialed in the bellhousing with the new motor and we installed a used Muncie behind it. When measuring for the driveshaft we discovered the output shaft splines were twisted and in a rush to get the car together for Drag Weekend we stole the Muncie from his Corvette to use (worked fine). Long story short, shortly after returning from Drag Weekend he ended up pulling the clutch and the transmission back out of the car to swap in a new clutch and the previously removed damaged Muncie which he had since rebuilt. From that day forward, it's always kicked out of 3rd gear. He did make a comment about the shim stock I had put between the block and scatter sheild and I'm wondering if maybe they didn't go back as previously installed.

As I recall, the sliders and internal splines looked good when he had it apart but I can't speak to that with certainty at this point as its been quite some time. Certainly worth looking into though.

As much as I hate to do it, it's sounding like that transmission should probably come out to check that scatter sheild again. Could it really be that far out to cause this? Would it not affect any of the other gears?

4th is on the input shaft, 3rd is on the main shaft. Bellhousing misalignment creates misalignment between the input shaft and the main shaft and is most likely to mess up high gear or third gear.

The 3-4 hub and slider are worn out,that's why it is jumping out of gear.

Yep that is the issue. Pull trans apart the clutching teeth should have chisel sharp edges, they will be rounded over and worn.

Synchro rings ?

Does that year Muncie have rooster combs shift levers for the shift rods or scissor type ?
If rooster combs have him check the check ball bearing engagement compared to e 1/2 lever engagement and rooster comb wear
Let us know wat you find please

The best thing about a Muncie, is they are fairly light, making it easier to toss it into a dumpster.

The transmission will be coming out hopefully in the next week or two. We decided to make a last minute go at the Power Tour West in my GTX so the 442 will be 2nd on the priority list for a bit while I get the GTX prepped. I appreciate the input though and will be sure to report back with our findings as soon as we get it pulled. Thanks to all. -Trent

Man, I REALLY want to do that power tour west. But we have a family Christmas party that weekend so I can't.

That's a bummer you can't make it. Would have been great to catch up. We don't get much activity over here on the West coast but when we do I try to participate. Some day I'll make it out East to one of the bigger events but with a wife and 4 kids, building a house and now starting a new business, it's hard to even justify keeping the cars some days let alone playing with them. I think that's partly why I decided to go though. The opportunity to create some good memories with the family and to get back in the seat for even just a bit should be good for soul. Some day I'll get out East though, some day...

That's a valid point... I have an E body 833 sitting on the shelf that has a GM input shaft already installed by a previously disappointed Muncie owner. I originally planned on undoing their butchery but this may be a game changer.

I tried to get the party date changed, but that went over like a pig roast at a PETA convention. I wanted to add those 3 tracks to my list, especially Pomona.

Well, that and that they power shift like a motocross bike. After I got used to banging gears with a Muncie, the doug nash and the 833 felt like a truck trans.

My experience was also that they shifted really well until they didn't shift at all.

Well, if we're talking about powershifting...over the last 50 years, I've had Toploaders, Muncies, T-10s, a T-5, a T-45, and numerous A833s in 23-spline and a couple 18-splines.

Of the bunch, the T-10 was my favorite for that; like throwing a switch.
The yardstick, as exemplified by the Greats like Ken Dondero & etc, is no RPM flare, just next gear.
The Tremecs and 833s require, for me at least, a more - shall we say - hostile attitude...

Update: Got the transmission pulled out and opened up. The teeth on the 3/4 slider don't look great and the teeth on 3rd gear don't look much better. Additionally, the slider seems to have more play on the hub than 1/2 in comparison so we placed an order for all 3 items. I can't speak with certainty as to what shape they were in when the transmission went together but will try to be investigative as it goes back together to determine if there are any other underlying issues or causes. It seemed like it didn't engage well on the bench when moving the slider into 3rd but I'll take another look when it goes back together, ultimately where the shift fork puts it. Lastly, I'm thinking we'll try to dial in that scatter shield again tomorrow with the shims that were there and see how things line up. I'm hoping it checks good. As previously said, I appreciate the input and will keep you guys posted as things progress... Thanks again! -Trent

If you haven't gotten parts, Check out Paul @ 5speeds. He's got some good stuff. I put his Zero-Rok sliders in the M-21 in my 55 and it's never shifted so smooth. Definitely worth a try.

https://www.5speeds.com/cart/index.php?route=product/product&path=75_17_69&product_id=102