A833 2nd gear grind under power when shifting

Posted By: mshred

A833 2nd gear grind under power when shifting - 06/18/11 05:32 AM

Hey guys,

got the car out riding on the street and I seem to be running into some problems with the 1-2 shift. Im using a vertigate shifter and when i go to shift from 1-2nd, especially when cold, it grinds going in. I decided to not really lay into it until it got warmer, and if i just accelerate like a normal car in traffic all seems to be fine on the shift. However under full throttle or even part throttle getting on it, it keeps grinding on the 1-2 shift, but not on the 2-3 or 3-4...this is most of the time though as I took my pops for a ride to see what he thought and low and behold it was okay on the 1-2 shift. At first I thought I may not be pushing the clutch pedal down enough, but i dont think its that (mind you i find that my pedal does go quite far so maybe im just not used to it yet? but its only from 1-2nd which I find fishy). Also sometimes when down gearing from 3rd to 2nd I find the same grinding occurs unless im really slowing down before going into 2nd

Im not sure what the problem could be...would it have to be a synchro that needs replacing? They all looked fine last time transmission was apart. I set the freeplay to the factory 1" of travel at the pedal spec, but it didnt make a difference (had closer to 2" before)

Any suggestions would be appreciated. Im really hoping the trans doesnt have to come out and taken apart again, but it seems to be looking that way. Its definitely not the shifter as I do have that dialed in nice (stop for second was too far in before and it would not engage 2nd fully and jump out...im wondering if that could have damaged the synchro?)

The trans is an a-body unit built in september 1969. The clutch is a centerforce dual friction and im using GM synchromesh fluid in it. It does seem to be leaking from the input shaft so im going to have to pull it to reseal that regardless. I do have the synchro to replace it as an old chrysler guy was gracious enough to give it to me, but im wondering if it even is a synchro issue? should I be looking for something else first before confirming its a synchro?

any opinions and suggestions are welcome!

Posted By: JohnRR

Re: A833 2nd gear grind under power when shifting - 06/18/11 07:18 AM

Make sure you don't have a clash with the reverse shift arm , the 1-2 slider is also part of reverse.

Posted By: mshred

Re: A833 2nd gear grind under power when shifting - 06/18/11 01:50 PM

Quote:

Make sure you don't have a clash with the reverse shift arm , the 1-2 slider is also part of reverse.

does the top cover have to come off for that? That was the problem I was having before i had the car running, I had the transmission locked up because when I was disengaging reverse it was hanging up on that slider..once I put the shifter on though it was working fine.

Is there a way to see if this is occuring by looking at the tabs on the sidecover while shifting it?

Posted By: JohnRR

Re: A833 2nd gear grind under power when shifting - 06/18/11 05:15 PM

Is the reverse detent working ? there is another thread on this someone else was having a problem wit htheir trans , the ball for the detent is MIA and the lever is not in the correct position when not in reverse

Posted By: mshred

Re: A833 2nd gear grind under power when shifting - 06/18/11 06:52 PM

Quote:

Is the reverse detent working ? there is another thread on this someone else was having a problem wit htheir trans , the ball for the detent is MIA and the lever is not in the correct position when not in reverse

the ball for the detent is there, i can gurantee that...whether or not its in the correct position though im not sure...when i had it apart it looked to be working fine

Posted By: JohnRR

Re: A833 2nd gear grind under power when shifting - 06/18/11 08:59 PM

Quote:

Quote:

Is the reverse detent working ? there is another thread on this someone else was having a problem wit htheir trans , the ball for the detent is MIA and the lever is not in the correct position when not in reverse

the ball for the detent is there, i can gurantee that...whether or not its in the correct position though im not sure...when i had it apart it looked to be working fine

Did you put the idler for reverse on correctly ? If yes then it's time to look at the syncro

Posted By: mshred

Re: A833 2nd gear grind under power when shifting - 06/18/11 10:16 PM

Quote:

Quote:

Quote:

Is the reverse detent working ? there is another thread on this someone else was having a problem wit htheir trans , the ball for the detent is MIA and the lever is not in the correct position when not in reverse

the ball for the detent is there, i can gurantee that...whether or not its in the correct position though im not sure...when i had it apart it looked to be working fine

Did you put the idler for reverse on correctly ? If yes then it's time to look at the syncro

yes, that I am positive about. Did it with my dad who is a mechanic and we made sure of that after the problems i had. I figure it is a synchro...damn i dont feel like pulling this thing out again

Posted By: scatpacktom

Re: A833 2nd gear grind under power when shifting - 06/19/11 02:59 AM

I understand you are "sure" that the reverse detent ball is where you think you left it but they can sometimes find their way into the bottom of the case.

The ball falls out and second gear will shift fine at low speeds, wind it up and without the ball its a no go.

I would just double check the symptoms you desribe are the "Ball"

Posted By: bboogieart

Re: A833 2nd gear grind under power when shifting - 06/19/11 03:05 AM

Read "manual trans problem" by EF8aar, on this very page. He had the same problem, and it turned out to be the detent ball.
Just saying.

Posted By: mshred

Re: A833 2nd gear grind under power when shifting - 06/19/11 05:49 AM

Hey guys, im not saying anyone is wrong or anything...I obviously won't know until I pull the side cover off, which has to be done whether its a synchro or the reverse detent ball. Took it for one more drive tonight and sure enough at WOT grinds going in- downshifting I had not grinding issues BUT it did pop out of second at one point in the night while driving. According to the other thread mentioned that I read through it seems that with no reverse ball getting into 2nd gear at all is impossible- such is not the case with my transmission, it just grinds noticeably going in.

My question is if it is the reverse ball that fell out, how do i prevent this from happening again?

Also, if it is the synchro, just replacing the brass ring should do the trick right? is there a way to tell the synchro is trashed and working no more?

Thanks all

Posted By: HPMike

Re: A833 2nd gear grind under power when shifting - 06/19/11 11:32 AM

Just replacing a brass ring will NOT necessarily fix your problem. You need to have a hard look at the gear itself, particularly the machined cone surface which interacts with the synchro ring. Lay a new ring on the gear, if there isn't much of a gap between the small dog teeth of the gear and ring(when viewed from the side), then the gear is likely the culprit. Not nearly as common as ring wear, but you do need to watch for this, especially if the unit had new rings when it was overhauled.

If all that checks out, and the dog teeth on the gear arent beat down from missed shifts, then take some 600 grit paper and sand the machined cone surface of the gear before you put it all back together. Also, if you are getting some "jump out of gear" issues, expecially on decel, then you had better take a hard look at the hub and sleeve for 1/2. Normally when these components wear out, the end result is the condition you are experiencing, especially if you had the linkage adjusted properly and the dog teeth on the speed gear are good.

MB

Posted By: 666

Re: A833 2nd gear grind under power when shifting - 06/19/11 11:44 AM

wondering if vg shiter is set up using the stops

Posted By: JohnRR

Re: A833 2nd gear grind under power when shifting - 06/19/11 02:13 PM

Quote:

Hey guys, im not saying anyone is wrong or anything...I obviously won't know until I pull the side cover off, which has to be done whether its a synchro or the reverse detent ball. Took it for one more drive tonight and sure enough at WOT grinds going in- downshifting I had not grinding issues BUT it did pop out of second at one point in the night while driving. According to the other thread mentioned that I read through it seems that with no reverse ball getting into 2nd gear at all is impossible- such is not the case with my transmission, it just grinds noticeably going in.

My question is if it is the reverse ball that fell out, how do i prevent this from happening again?

Also, if it is the synchro, just replacing the brass ring should do the trick right? is there a way to tell the synchro is trashed and working no more?

Thanks all

You can't see the detent for reverse pulling off the side cover , you have to disassemble the detent itself and fish out the ball with a magnet

Posted By: mshred

Re: A833 2nd gear grind under power when shifting - 06/23/11 01:56 AM

well i have the transmission apart and everything has checked out okay. Synchros grab good and are not worn on 3-4 or 1-2. the machined cone surfaces are in great shape, as are the teeth on the hub and sliders. I have looked at the cluster gear as well and it all looks to be okay.

checked the reverse ball and detent and sure enough its all there

There is a tight spot in reverse that i had an issue with before i even put the transmission. Sometimes i run into this tight spot when trying to engage reverse and it wont go in so i have to let it roll forwards or backwards until it wants to go. Could this tight spot on the gear be affecting the 1-2?

Only other thing I can think of is that the stops arent set properly, but the stop for 2nd was just recently adjusted since it wouldnt stay in before. Im almost thinking its still wrong

what do you guys think? I am now totally stumped..i thought it would be synchros or what else was mentioned, but its not

Posted By: Cuda340

Re: A833 2nd gear grind under power when shifting - 06/23/11 01:47 PM

Just a suggestion, you said you are using the GM syncromesh fluid, maybe for your application try the GL-4 Rated 80-90wt gear oil, or the Passon performance fluid. It's possible when things heat up the syncro is not grabbing the cone enough maybe the fluid is too thin or incorrect. Also check your shifter linkage throw to see if reverse is being fully released to the detent, so it can't slide over and lock 2nd gear up.
Another thing is if you are making some good power and your engine mounts are bad the engine might be torqing too much and the z bar moves, not letting the clutch release enough.

Posted By: BADDART

Re: A833 2nd gear grind under power when shifting - 06/23/11 07:38 PM

I have bench adjusted the shifter stops too tight more than once. Just unscrew the stop all the way out and try some shifts to see if the grind is gone.Readjust stop inward as necc.Clutch plate departure is also very important-but you stated the other gears shift fine.Are you shifting all gears at same rpm? Check for deflection in linkage as previously suggested. Good luck. Chris

Posted By: mshred

Re: A833 2nd gear grind under power when shifting - 06/24/11 03:20 AM

Quote:

Just a suggestion, you said you are using the GM syncromesh fluid, maybe for your application try the GL-4 Rated 80-90wt gear oil, or the Passon performance fluid. It's possible when things heat up the syncro is not grabbing the cone enough maybe the fluid is too thin or incorrect. Also check your shifter linkage throw to see if reverse is being fully released to the detent, so it can't slide over and lock 2nd gear up.
Another thing is if you are making some good power and your engine mounts are bad the engine might be torqing too much and the z bar moves, not letting the clutch release enough.

Shifter linkage is good, I have checked it more than once for this problem. As far as the z-bar flexing goes, I guess the only way to solve that is a torque strap since there's really no way to see if its flexing when i shift while driving.

As far as the fluid goes, im starting to think this may be what it is. I have been told that synchromesh does have synthetic additives in it. Finding GL-4 gear oil here is like finding a needle in a hay stack...was thinking of trying ATF since it seems quite a few people use it with no problems, but im not sure what type of ATF would be suitable? Dexron? Mercon? Type F? multi purpose?

I still have the drained synchromesh fluid that I can put back in, but i thought id try something else first to see if it helps the problem go away

Posted By: mshred

Re: A833 2nd gear grind under power when shifting - 06/24/11 03:22 AM

Quote:

I have bench adjusted the shifter stops too tight more than once. Just unscrew the stop all the way out and try some shifts to see if the grind is gone.Readjust stop inward as necc.Clutch plate departure is also very important-but you stated the other gears shift fine.Are you shifting all gears at same rpm? Check for deflection in linkage as previously suggested. Good luck. Chris

Hey Chris, it doesnt even matter what rpm it is, under any kind of partial or full throttle it grinds going in...all the other gears are fine when im on them hard or just cruising into them

I double checked the stops today and sure enough there is actually quite the gap on the 2nd gear stop....so now im thinking maybe its the fluid?