1st to 2nd too hard under load.

[mickey356]

Ok, I switched to a Rennshift set at 20% reduction and shifting, up or down, with rpms @ 2500+ is "tight". I really have to force it into 2nd. If I just casually accelerate and up shift, or decelerate and downshift it isn't as bad.
So I thought "coupler & bushings", right? I just put a wevo coupler in and replaced the shift rod bushings (that's was fun, not!) and it's really no better. The rest of the shifting is VERY much improved but the "2nd issue" still exists. While I had the shifter out I also went to 33% reduction.
The PO had 1st & 2nd rebuilt about a year before I bought it so I don't think it's the gears or synchros, but then again the crap shop that did the horrible PPI on my car also did the tranny too, so I guess it's not out of the question.
What am I missing? What else could cause this forced shifting at higher r's?
Thanks

[Oh Haha]

Are you trying to "speed shift" or is it difficult to get into 2nd after pausing between 1st and 2nd?

If try to beat the synchros it will be difficult to go into gear.

You may want to adjust the coupler again.

[john walker's workshop]

short shifters decrease leverage, so that's not helping things. if you have swepco in there, try kendall 80/90. see the swepco thread.

[efhughes3]

That's why short shifters aren't all they're cracked up to be, IMO. They can also hasten the demise of a weak aspect of a trans.

[mickey356]

The tranny fluid was changed when I had the top end done about 1K ago. I think they put redline in but I'll double check. If I can get my hands on some Swepco or Kendall I will. Either way, I'll drain and refill.

Speed shift? Maybe, I'm a little "anxious" to get up to speed. I don't feel like I am but I'll see how it responds to a more civilized approach. I just figured it wouldn't give me any guff, but maybe I am being too quick. I know these cars aren't known for their off the line speed but on a track you'd like to think coming out of a hairpin you don't have to treat it like you're out for a sunday drive. Maybe it's just me? (Not that I've been on a track but I'm hoping to do some DE's at some point)

I can tinker with the coupler and see if that helps but I was pretty proud that I got it the first crack, all 5 gears and reverse!
I'm also gonna check the engine and trans mounts and see if it needs a clutch adjustment. And I may go back to the 20% reduction as well, it's not all that much of a difference, it's there but not HUGE. I won't be able to get it on a lift until next week so I guess I'll just deal with it until then.

Thanks again for the help.

[efhughes3]

It would be a rarity to have to go down to 1st gear at a track, and going to 2nd is Really the one you need the slightest pause during shifting.

[mickey356]

Originally Posted by efhughes3

It would be a rarity to have to go down to 1st gear at a track, and going to 2nd is Really the one you need the slightest pause during shifting.

True. I can't imagine you ever really need 1st at a track other than starting, I was just trying to make a point about about being able to shift quicker. But it does make me wonder what folks do when the have a quicker revving engine, I guess it's all relative. Or maybe they have a trans built to better suit the quicker revs?

I did go out for another more "civilized" spin and yes, you're right, it does shift from 1st to 2nd better if I give it time. However, downshifting from 3rd to 2nd its still very hard and I wasn't trying to zip around the corner or anything. Something ain't right.

[efhughes3]

3rd to 2nd should indeed be smooth. Maybe the check of the coupler may be in order-just to be sure.

Trans mounts could be something to look at too.

[john walker's workshop]

[QUOTE=mickey356;5435660]
If I can get my hands on some Swepco or Kendall I will. Either way, I'll drain and refill.

QUOTE]


kendall is what you should try. did you read the swepco thread? Swepco Transmission Fluid Question

[mickey356]

I did John, thanks. I will see if I can find some in my area.

[Trackrash]

Not sure what transmission you have. I had what sounds like the same problem in my '71. If I paused during my shift from 1st to 2nd there was no problem. If I shifted straight through to 2nd it would not want to go into gear.
The fix was to re-adjust the shift forks in the transmission. Due to wear what was happening was the 2nd gear synchro was starting to engage before 1st gear was released. I spent years chasing this and getting the shift forks in the trans right finally fixed it.
Now I shift straight from 1st to 2nd without any problem. (sorry it is still impossible to speed shift the 901 or 915 transmissions)

[mickey356]

OK, started fooling around with the coupler today and now it's nicking 4th and reverse (I think) when I down shift out of 3rd & 5th. Also from second to 3rd it goes to 5th easier, like it's being guided, instead of 3rd. I guess I have some fine tuning to do but I'm having hard time sorting through the info (threads) - I have a Rennshift so the "Pulling it to the leff" approach kinda screws with the way the Rennshift sets itself in the 3rd 4th plane in neutral, yes? I guess my question is is there any difference in how you adjust the coupler when you have a Rennshift or Wevo shifter?
I'm close I guess cuz I have all the gears, but it's nicking a bit as mentioned. And it hasn't seemed to do anything for the original problem.

[Oh Haha]

WEVO recommends putting the shifter into 3rd when doing the coupler adjustment. One could assume the same for the Rennshift.

Make sure your coupler set screw locks down tightly so that when you get to the sweet spot it doesn't move.

[mickey356]

Thanks guys.
I've got it pretty close right now I think. No more grinding or nicking per se, but I still have the "2nd" issue. While I was out drivng it occured to me that it shifts into 2nd "better" under normal accelreation, but when I'm slowing down to make a 90* turn at an intersection I slow down, put the clutch in which of course brings the revs down to the 950rpm range and thats when I have a hard time getting into 2nd. If I blip the throttle and bring the revs up a bit it seems to shift a litte easier. but still not seemless. It's the same characteristic of shifting from 1st to 2nd when I'm getting on it a bit.
I hope I explained it well enough that someone may be able to give some insight on that issue.
I don't think it's the shift linkage (coupler) so I'm trying to figure out if these characteristics are indicative of a problem with the clutch, clutch cable or transmission. I know it's hard to say without actually driving the car but if what I've explained is telling of something someone else has dealt with it may save me some time chasing this with adjustment after adjustment, trans fluid, etc..... hopefully I can focus my efforts somewhere more specific. Thanks again for the help. (first I put a new shifter in, then a coupler, then............... only to find out it was ????)

[Oh Haha]

Are you pausing between 1 and 2 during acceleration?

I know it's tough to resist but you must build that habit into driving a standard 915 box. I still rush 2nd once in a while if I'm getting on it.

It sounds to me like the rest of your setup is adjusted correctly and working as it should.

[tcar]

Originally Posted by mickey356

If I can get my hands on some Swepco or Kendall I will.

NO. Read the thread that he mentioned.

Use Kendall. Don't use Swepco.

[dentist90]

Originally Posted by john walker's workshop

short shifters decrease leverage, so that's not helping things.

This is what I'm thinking the problem is. Did you go from a factory shifter to -20% Rennshift (and then to -30% Rennshift)? If your 2nd gear was a bit baulky to begin with, the shorter shift throws will only magnify the problem. After my transmission rebuild 2nd is SO much easier to shift into, but it is still my stiffest gear. I've got a factory short shift kit. I imagine if I went back to the stock shifter 2nd would be even easier.

Your description of having to match revs (blipping the throttle) to get 2nd to slide in easier suggests that the syncho ring on 2nd may not have enough friction to spin up the input shaft. Perhaps it is worn and polished already (hopefully the mechanic who redid 1st and 2nd gears didn't just flip the synchro rings). A change of oil may help with this... but only for so long

[CCM911]

Are you heel-toeing on the 3-2 downshift? I do it all the time, and it is just the trick to get into second without drama. When you get to the track, you will see how important this becomes.

[Drisump]

On the way up from first to second I find that the smoothest change is accomplished by a slight pause and a slight "blip"( yes, on the upshift), and on the way down, pretty much the same... maybe a little a little more "blip". I don't have a short shift installed so I can't comment on them, but what John says makes sense ( less motion to achieve the same work equals more force). When I was a kid I used to drive large trucks with 18 speed Fullers and the owner of the company wanted the clutch only to be used to start off and speed shift thereafter. Gotta say,if you wanted a seamless shift (which I did), you had to be very sensitive to what was happening in the box and the one big advantage was left foot braking while downshifting.....no need for heel and toe. I wonder if the Redline product that was is your car was synthetic, if so, the diff oil thread will warn you about their use in 915's. I initially installed Amsoil syn in my car (not knowing better) which improved the shifting rather noticeably from what was in there before (don't know what product it was,but new vs. old oil). Just recently changed the Amsoil (after 9000 miles) for Swepco (couldn't find Kendall) and yeah the tranny's performance improved once again.....it practically shifts itself now...LOL. Cheers

[mickey356]

After much fussing and driving and talking and reading and..... I think it all boils down to a problem that existed and is now exaggerated by the new shifter, the syncro is likely bad. After all I went through with this car to this point I'll just bring the new shifter back to 20% reduction, put some kendall 80/90 in and use some finesse. I don't have the time or money to do any trans work right now. Worst part is 1st and 2nd were rebuilt before I bought it. It was done by the same shop the did my PPI (which was dreadful) so I guess I shouldn't expect anything else. I'll sort it out properly when the time comes.
I appreciate the help. Does anyone have a lead on where I can score some Kendall in the Philly area? I've checked all out local spots and no one stocks it, or at least none of the places I know.