M20 shifting problems w/ Hurst Shifter....

[AllGoNoShow]

Previous owner put a supposedly rebuilt M20 in my 1968 C10 with a Hurst Competition Plus 4-Speed Shifter. Have only driven it probably 20-30 miles and during a somewhat spirited 3rd to 2nd downshift, the tranny got stuck in 2nd gear (with the gear shift lever stuck in the neutral position).

I was able to nurse it home in 2nd and removed the shifter hump to take a look at things. I just messed with the gear shift levers and it suddenly freed itself up. I adjusted the shifter using the "alignment hole" per Hurst instructions (using a 1/4 drill bit), and am still having issues. It appears the 1-2 shift lever wasn't fully clicking into the neutral position (it would be close but was still hanging up somewhat, preventing a shift over into the 3-4 gate). Was able to adjust that rod a little shorter and address that issue, but now, randomly, it appears that on the 2nd to 3rd shift, the 3rd-4th shifter rod is binding and it either takes a ton of effort to slam it into 3rd gear or it will free up if you go into 4th gear from 2nd instead of 3rd. It only binds like this 1 out of 6-8 times of going through the gears (I'm doing this all with the engine not running at this point).

I popped the rods off the shifter and it seems the 1-2 and 3-4 shift lever rods on the actual transmission take excessive effort to get to click into position. I'm wondering if I should be pulling the side cover and inspecting the shifter forks- can you adjust these at all to free them up? What should I be looking for?

Any tips would be helpful.

Nick

[AussieinNC]

Originally Posted by AllGoNoShow

Previous owner put a supposedly rebuilt M20 in my 1968 C10 with a Hurst Competition Plus 4-Speed Shifter. Have only driven it probably 20-30 miles and during a somewhat spirited 3rd to 2nd downshift, the tranny got stuck in 2nd gear (with the gear shift lever stuck in the neutral position).

I was able to nurse it home in 2nd and removed the shifter hump to take a look at things. I just messed with the gear shift levers and it suddenly freed itself up. I adjusted the shifter using the "alignment hole" per Hurst instructions (using a 1/4 drill bit), and am still having issues. It appears the 1-2 shift lever wasn't fully clicking into the neutral position (it would be close but was still hanging up somewhat, preventing a shift over into the 3-4 gate). Was able to adjust that rod a little shorter and address that issue, but now, randomly, it appears that on the 2nd to 3rd shift, the 3rd-4th shifter rod is binding and it either takes a ton of effort to slam it into 3rd gear or it will free up if you go into 4th gear from 2nd instead of 3rd. It only binds like this 1 out of 6-8 times of going through the gears (I'm doing this all with the engine not running at this point).

I popped the rods off the shifter and it seems the 1-2 and 3-4 shift lever rods on the actual transmission take excessive effort to get to click into position. I'm wondering if I should be pulling the side cover and inspecting the shifter forks- can you adjust these at all to free them up? What should I be looking for?

Any tips would be helpful.

Nick

What viscosity oil do you have in the trans?

Too heavy and the synchros bind up and prevent shifts...

[AllGoNoShow]

Originally Posted by AussieinNC

What viscosity oil do you have in the trans?

Too heavy and the synchros bind up and prevent shifts...

Don't really know what the previous owner put in there but I ordered up some 80-90w GL4 along with a new steel bushing rebuild kit for the shifter.

[Molino]

Originally Posted by AllGoNoShow

Don't really know what the previous owner put in there but I ordered up some 80-90w GL4 along with a new steel bushing rebuild kit for the shifter.

Those steel bushings are a good place to start. Checkout Paul Cangialosi on YouTube. He is a gearbox guru and he has a bunch of videos on rebuilding shifters and trannies that are very entertaining and informative. If you call his shop he will answer the phone and he will answer any questions that you have. I’d start with the vids he’ll show you what to look for.

Russ

[AllGoNoShow]

Replaced bushings, adjusted the Hurst Comp plus shifter per instructions, and changed fluid. Went for a drive and after a spirited 1-2 shift it got stuck in 2nd gear again while on my way to 3rd. Nursed it into a parking lot and sure enough the 2nd gear lever was not pulled all the way into neutral position (it was close but just off keeping it in gear)- was able to move it back and it freed it back up and I was on my way. While normal driving, I’m having still having issues getting into 3rd from time to time.

Shifter looks brand new....starting to think it is something internal. I’ve never had a car fight me so much on every little thing I’ve done to it! What a PITA

I may just try adjusting the shifter arms by trial and error (and the alignment hole won’t line up per Hurst instructions) to see what happens.

[AussieinNC]

Sounds like a weak spring on the inside of the shift lever cover...

Strung between the interlock levers...

[geezer#99]

Originally Posted by AllGoNoShow

I may just try adjusting the shifter arms by trial and error (and the alignment hole won’t line up per Hurst instructions) to see what happens.

Of course the alignment hole lines up.
Pop the levers off, line up the hole and slide a 1/4 inch Drill bit in there to keep it in alignment.
Then hook up your rods and levers.

[AllGoNoShow]

Originally Posted by geezer#99

Of course the alignment hole lines up.
Pop the levers off, line up the hole and slide a 1/4 inch Drill bit in there to keep it in alignment.
Then hook up your rods and levers.

Yes, that’s what I already did to adjust it to Hurst’s specifications (and the 2nd gear is still hanging up). I was just saying I may try to mess with the adjustment (which would put it “out of alignment” per Hurst’s specifications) just to see if I can get it to release 2nd gear better and get it into neutral on the 2-3 shift.

May have to pull side cover just to take a look for that spring.

Or I may just say F-it and put the Tremec TKO currently in my long parked camaro in it and call it done.

[geezer#99]

Maybe the problem is internal on the shifter body.

[geezer#99]

Do you have a pic of the shifter showing the body and rods?

[Molino]

Originally Posted by geezer#99

Maybe the problem is internal on the shifter body.

I have to agree with Geezer. It sounds as though the shifter is entering the neutral gate before the transmission is completely pulled out of 2nd gear. Then the shifter is in neutral but the transmission is still in 2nd gear.
The above mentioned spring and interlock bars prevent the transmission from entering two gears at the same time. Try to inspect the action of the shifter to see how much play In the 1-2 and 3-4 levers occurs during the 2-3 shift. The alignment hole has to line up as that is the neutral gate of the shifter. It sounds as though you may have excessive play in the shifter box.
I would remove the shifter box and do a disassembly, clean and inspect and reassemble making sure to inspect all parts for wear. Shifter boxes do wear out and get loose and sloppy. Nobody likes loose and sloppy. The boxes can look new on the outside but have worn shim plates an associated parts on the inside. A properly installed and maintained Hurst shifter should feel rock solid and almost fall into gear with a little guidance.

[AllGoNoShow]

Does anyone have a good source for Muncie parts?

I can’t believe it has anything to do with the shifter unless it has a manufacture defect- when I say it looks brand new, I mean there is no signs of any type of use on it. I will still take a better look at it, but I disconnected the linkage on the side cover arms again and just messing around with the 1-2 lever, it appears that sometimes it is not finding itself into the neutral position but like it almost finds another (4th) detent position that is just shy of the true neutral position so it’s still in 2nd gear. I’m going to pull the side cover and take a look at that spring as well as the detent arms to see if maybe one is cracked or worn so bad it’s not popping all the way into the neutral position.

[AussieinNC]

Here is a link to the shifter spring inside the shift cover...

https://www.ebay.com/i/132311680833?...SABEgJOIvD_BwE

If the end of the spring is broken off, you must find the broken pieces or they could kill the gears if they get jammed in the gear sets.

[AcampoDave]

www.5speeds.com is a good source for Muncie parts.

[Mike C]

Make sure your shift arms are correct for a Muncie and not another trans... Saginaw, BW, etc.

Also make sure bracket that holds shifter is tight to the trans.

[AllGoNoShow]

Well I pulled the side cover today- the 1-2 detent swing arm was slightly bent and also had a small chunk worn off of it between what would be 1st gear and the neutral position. The 3-4 shifter fork looked awfully worn with a nice ridge on it. Picture of gear-set below-what do you guys think? 3rd and 2nd gear sycros are obviously more worn than 1 and 4 but from what I have read that is to be expected. Tranny sure doesn't look like it had a full recent rebuild though as previous owner claimed.

What I did notice, however, and what I expect has been causing some of my problems- the previous owner bought the wrong installation kit (the one for the later muncies with the shift levers attached with bolts, rather than the early muncie that I have with the shift levers attach with nuts). It seems that the only difference with these two kits (#3733163 for the early muncies and #3737834 for the later ones), is the shifter lever arms have different holes to accomodate the studs vs. the bolt attachment methods.

But, more importantly, it appears he put the 1-2 shifter lever on the 3-4 and vice-versa....and the two shifter levers are canted slightly differently and one has the hole about a 1/4 lower. Everything I have read says that the 7060 stamped shift lever is the 3-4 and he had it in the 1-2 position. So if anyone has a hurst competition shifter, can you just verify that for me (with the levers in the right position it appears that the stamped numbers should all be facing out anyway from the tranmission).

I ordered the new detent arms and shift forks from 5speed.com....once I get everything back together I will update you with results.

[AussieinNC]

If it were mine I would be pulling it and replacing all of those synchros...I cant see the back space on the 2nd gear as the slider is over the gear....

The 3rd gear synchro has little backspace left...once it is resting hard against the back of the gear the synchro cant work correctly.

Did you order a new spring as well as the shift forks?

[AllGoNoShow]

Yep....got the new spring too.

If I pull the tranny to replace the synchros I may as well just put my Tremec in it. We will see how it does. When you talk about backspace what exactly are you looking at?

[AussieinNC]

Backspace I am referring to is the gap between the back of the brass synchro and its mated gear surface...where the little metal dogs are located.

Item 1 in the illustration below is the gear wheel, Item 2 is the Synchro...

Backspace is the gap at the back of the synchro unit when it is mated to the tapered face of the gear wheel.

[AllGoNoShow]

Well after new forks, new scissor dent arms, new spring, some new GL-4 lube, and the shift lever arms on the right gears (5speed.com has some special clips that adapt the late model Muncie shift lever arms to work with the early model), it shifts better then ever and I have had absolutely no problems with it.

[AussieinNC]

Originally Posted by AllGoNoShow

Well after new forks, new scissor dent arms, new spring, some new GL-4 lube, and the shift lever arms on the right gears (5speed.com has some special clips that adapt the late model Muncie shift lever arms to work with the early model), it shifts better then ever and I have had absolutely no problems with it.

Glad it worked out well for you...safe driving...

[AcampoDave]

Me too, I like 5speeds.com