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Discussion Starter · #1 ·
I have a 67 with a small block & a 5 speed Tremec. After purchasing the WHOLE kit including the bellhousing, I seem to have a shifting problem. The trans does not like to engage 1st & 2nd very well. I used a dial indicator to check for runout in the bellhousing & all other procedures were to spec. The car has a hydraulic clutch slave which seems to disengage very well. Furthermore, under power, shifting between 1st & 2nd is not as good as it should be. The kit is from Keisler and I have found a few things to make me suspicious. It is not my intention to fault the manufacturer. Does anyone have any constructive input?

Thanks,

Tim:clonk:
 

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A '67 is pretty light and unless you have tubbed it to install steam roller slicks I doubt you are going to create that much chassis flexing from engine torque because the tires will slip instead. But to cover all angles what motor are you running with the T-5 (and I have to ask what was the donor vehicle), and do you know or can you give a good guestimate of the engines torque? Further, what kind of suspension mods have you made, and do you have a cage?


Big Dave
 

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Discussion Starter · #3 ·
Dave,

Thanks for the input. The engine is a NAPA crate engine. It is a 350 with ported vortec heads, roller cam with 218 duration @ .050. The engine was dynoed at 459 h.p. with 450 lb of torque. It carries 400 lb. from 3300-5900 rpm. What makes you ask?

Thanks,

Tim:thumbsup:
 

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The shift rails are internal on the Tremac and should not give any bother with any gear selection. If the case is flexed due to excessive torque it could bind the shift rails in the case. To control torque on many race cars the engine employs solid motor mounts (and in extreme cases front and rear motor plates). If your rear end is not controlled properly by the springs (I'll bet you have mono leafs) it will do the bunny hop, and that violent loading and unloading of the springs will travel back up the drive shaft (which in this case is acting like an old fashion torque tube) flexing your transmission case.

I would recommend you install some CaTrac traction bars or the Competition Engineering equivalent version of them before you break the case of your tranny. Remember that though Aluminum is relatively malleable it work hardens very quickly becoming brittle.

If you do install solid motor mounts (or my favorite polyurethane) remember to include a transmission mount in the change over.


Big Dave
 

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Discussion Starter · #6 ·
Dave,

You must be a mind reader. I have a date with the local chassis guru for custom frame connectors and traction bars as you suggested.

Thanks,

Tim
 

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I understand that Tremec changed to a nylon pad on the shift forks inside the trans and that these are breaking causing shifting difficulty.

Apparently these pads need to be changed back to metal (bronze or brass I think). I am having this exact same problem with a TKO-600 behind an LS3 in a C-10 pickup. The distributor said to send the trans back and they would fix it. I would suggest calling Keisler and discussing this with them.
 

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My experience is very recent (don't have repaired trans back yet). Up until this I've heard nothing but good about the TKO. Hopefully they'll get it fixed quickly.
 

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Well...I just called Tremec about this problem and they confirmed that they use plastic shift pads on the clutch forks but the tech guy said that they were not having any problems with them. He also confirmed that some guys were replacing the plastic piece with a bronze piece but he said he didn't think that would help the shifting. In the discussion he said that the TKO doesn't shift as quickly when revs get up around 6000 RPM (mine just refuses to go in gear). Since I'm running an LS3 with the rev limiter set at 6500 that must be my problem. He recommended Liberty for modifications that would help the TKO shift at higher RPM. I'll either have to check that out or switch over to the T56 Magnum which apparently has a more modern design and doesn't have this problem.
 

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Bigger gears have more surface area for the syncro rings to act upon and therefore spin them up faster. Cuting off teeth on the gear and syncro rings makes a stuborn gear shift work more easily, but ruins the trannys street manners (they are called crash boxes for a reason). Of course the down side to a bigger gear is in that they have more mass which is harder to accelerate up to speed. And since mass increases with the cube of the gears dimensions, compared to only the square for the area, it can become a problem also. You might have to decide just which area of your driving will be favored in transmission choice since the only gauranteed solution is a planatary gear box like Lenco sells.

Big Dave
 

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Ya know, I have heard about a lot of issues with shifting in the TKO trans. Main concern for me was the high rev shifting. My shift point is at 6800 and I have never (knock on wood) missed a shift. However, I have 2 friends that have the same trans and can't get the gears above 6500. Mine shifts smooth and feels great.

Its always interesting to hear others input on the same products that I have, such as the TKO.
 

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Tremec has a very strict break in procedure, including no load shifting with the car on jack stands for IIRC, 10 minutes. then a 500 mile city type driving break in with no gear slamming. I did all of that (was really hard to drive it easy for so long) and have had no problems. Mine has been shifted hard a couple of times above 6200 rpm's and was smooth, but we do go there any more :)
 
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