trans get hot= no shiftie??, what the flux?? Options

[aircooledboy]

I have had this problem since I put the 8 back together, but it has gotten really bad lately. I'll be pulling the trans this winter to get taller gears, but I'm curious what you guys think. (IMG:style_emoticons/default/idea.gif)

When I start out, the trans shifts perfectly, as good as any modern car. But after about 15 minutes, things go south. I'll go to put the clutch in, and it will be stiff toward the bottom. Then, the next time I put the clutch in, it will stop about an inch or so from the bottom. If I muscle it, it will make a "pop" and go the rest of the way. At that point, even if I crank it to the floor, it is very hard to get into any gear. It then continues that way until I shut the car off, and let it sit. The next day, without fail, it will shift perfectly again, until it starts all over again. I was sure my clutch tube was breaking free until it healed itself overnight. It has done that 5 times now. When it is acting up, it will not go into reverse, not matter what.

My WAG is the pilot bearing. I used a KEP bearing, because I am a cheap bastard ( I know, a cheap 914 owner, who ever heard of that (IMG:style_emoticons/default/w00t.gif) ), and it was less than half what Rennegade gets. But when I was at Rennegade this summer, they told me the reason the KEP is so much cheaper is because KEP uses an aluminum ring, and Rennegade uses steel. Renegade claims that the aluminum allows the bearing to walk when it gets hot. I scoffed at the time, but now I'm not so sure. What do you guys think (IMG:style_emoticons/default/pray.gif)

[john rogers]

When we built my race car 914 we did not use any "cheap" parts in the drive train, especially if they were somewhere's that had to have a lot of disassembly done to get to them. Clutches and t/o bearings come to mind as do the bearing and other parts in the trans or inside the engine. Sounds like the t/o bearing has gone south......

[Series9]

Hmmm, I haven't seen a failure like this before.

What's so strange to me is that it's temperature related.

The pilot bearing is suspect, but once they go south, they don't tend get better when cold, and I don't see how it could affect pedal travel.

It seems obvious that your clutch is failing to completely disengage when the car's warm. Regardless, the pedal action you describe seems indicative of an imminent failure. I wouldn't take the car too far from home until you can get into the bell housing to check things out.

I look forward to hearing the report.

[aircooledboy]

When we built my race car 914 we did not use any "cheap" parts in the drive train, especially if they were somewhere's that had to have a lot of disassembly done to get to them

In retrospect, and for future applications, that seems like a good policy. (IMG:style_emoticons/default/laugh.gif)

do you have an aluminum intermediate plate in the transmission???

I don't know. This is the trans John had, and it was rebuilt before he got it. It doesn't have the obvious color difference I have seen with some aluminum plates though.

What's so strange to me is that it's temperature related. I don't see how it could affect pedal travel.

I agree. That threw me too, but of course I don't know much about transmissions. I was thinking that if the pilot wasn't holding the input shaft true, the TO would bind as it got closer to the end of the shaft. Hard to imaging that it would go from perfect to unshiftable to perfect if that is the explanation though, huh?

It seems obvious that your clutch is failing to completely disengage when the car's warm. Regardless, the pedal action you describe seems indicative of an imminent failure. I wouldn't take the car too far from home until you can get into the bell housing to check things out.

Amen there, brother. I had adjusted the clutch this afternoon, and thought I had solved the problem (thinking that the nut had just loosened because it is not double nutted). I went for a spin and the shifting was better than ever initially. I downshifted for my last turn before getting home, and the BS started again. I'm glad it did though, as I had convinced myself the problem was solved, and I could take it when I went about 100 miles from here for work in the morning. (IMG:style_emoticons/default/ohmy.gif) No more trips more than 5 minutes away until i get her sorted, which likely won't be this year.

Oh well, I'm on borrowed 914 time in these parts anyway. First salt could hit the road any day now, and out here, they use it like it was going out of style. (IMG:style_emoticons/default/monkeydance.gif)

[slivel]

I have definitely experienced shifting problems that are temperature related. Before installing a pump and cooler I would see trans temps of over 300 degrees in the summer after a 30 minute track session. I used my infrared gun to shoot the side of the case and check temps - the one I use for checking tire temps. Also would start leaking at the front seal.

Steve

[aircooledboy]

I also have some leaking (more like weeping) at the front seal. Just enough to have one drip at the bottom of the bell housing, but almost never leaves any on the ground.

BTW, trans is filled with Swepco, which I have read some mixed things about. I have no idea how that could possibly contribute to my pedal feel, but I thought I would mention that.
"That makes no sense to me, but then you are very small". (IMG:style_emoticons/default/smoke.gif)

[tommy914]

Any chance that the clutch cable is too close too something hot, like the exhaust, and getting too hot to operate correctly?

[Red-Beard]

If you are having pedal problems, it is clutch related. What is the condition of the cable?

I had a problem with my clutch tube where the cable didn't seat properly. THEN, it did. I thought I broke the tube, but it adjusted out fine.

My point is, look at the clutch, cable, pedal cluster, etc. I doubt this is a pilot bearing issue. That would be more of a disengagement problem.

[914GT]

I suppose it's possible the pilot bearing could be binding if it wasn't driven far enough into the crankshaft, but as Red-Beard said that doesn't explain the clutch pedal behavior. Maybe the release bearing is getting hot and binding on the release bearing tube? Was the bearing and tube in good shape, with a little lube so the bearing slides in and out easily?

[SpecialK]

Any chance that the clutch cable is too close too something hot, like the exhaust, and getting too hot to operate correctly?

(IMG:style_emoticons/default/agree.gif)

I'm with Tommy on this one, sounds like the clutch cable could be expanding with the heat, and shrinking back to it's original size (working correctly) after it cools.

Easy way to test this would be to wrap the clutch cable with some of that thermal sleeve stuff, or another heat reflective tape. If it fixes the problem, cool!! If not, then you can mark that off the "possibilities" list.

Are your headers wrapped?


Kevin

[aircooledboy]

Headers are not wraped, but the clutch cable doesn't really get very close to them.

The cable itself is on good shape and well seated, but the threads at the trans end are flatened to an unusual degree. That is why I thought maybe the adjuster nut had walked back a bit.

After reading Guy's thoughts, I think he may be onto something here. The fly/disk/press plate asssembly on an 8 is much thicker than a stock set up. Even without the clutch cable attached, the TO is in contact with the press plate. You have to adjust the cable in even more from there or the TO fork chatters against the opening in the bell housing. I wonder if the TO is getting cooked from riding against the press plate all the time, and now when it heats up, it binds. (IMG:style_emoticons/default/idea.gif)
Of course, I'm the same guy who thought it was probably the pilot bearing about 24 hours ago. (IMG:style_emoticons/default/w00t.gif) (IMG:style_emoticons/default/monkeydance.gif)

[Brad Roberts]

Ha ha... The KEP parts are fine. I had the EXACT same problem with a V8 conversion car... yanked the tranny and installed a loaner that shifts FINE. It is in the tranny. The intermediate plate is worn out causing the shift forks to "cock" in the bore when it gets hot.

I battled this for months.

Common denominator: Renegade supplied tranny. Called the builder... he asked me to ship it back to him.

The V8 crank doesnt care what pilot bearing adapter is in there.


B

[ArtechnikA]

The intermediate plate is worn out causing the shift forks to "cock" in the bore when it gets hot.

i'm confused. how does that keep the clutch from operating ?

[aircooledboy]

Not a Renegade trans. Was in the car when John bought it, and he was told it was a recent rebuild (when it is cold, it shifts better than any 914 I have ever driven).

[Red-Beard]

How does a worn out intermediate plate cause problems depressing the clutch pedal?

[aircooledboy]

Got my trans back from Brad Mayeur a couple weeks back, and I am pretty sure he solved my hard shifting mystery. I had not lubed the inside of the TO when I reassembled the trans to the motor, and apparently no one else ever had either. (IMG:http://www.914world.com/bbs2/html/emoticons/unsure.gif) Ooooppps. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) The TO tube had a notch worn into it about 1/8" from the end. When the trans and clutch were cold, the TO would slide past the notch with no noticeable resistance. But when things warmed up, everything would expand just enough that the leading edge of the TO would catch on the notch, preventing the clutch from fully releasing, and preventing me from being able to shift. (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif) The KEP V8 clutch set up requires a longer throw than stock, so I am pushing the geometry of the stock set up right to its limit. When the KEP clutch has released, the arc of the end of the TO fork has actually gone just past the apex, and started to pull down on the TO against the TO tube ever so slightly. Properly lubed, it won't be a problem. No lube (duh, it that a bad thing?), and it will wear and eventually catch.

So, boys and girls, the moral of the story here is don't forget to put some moly grease in the groove around the inside of the TO whenever you have the engine and trans apart. I understand I may well be the only dumbass who didn't already know that, but just in case. . . (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)
BTW, Wifey called to tell me my new clutch set arrived from KEP today, so with a little bit of luck, and one more good rain to wash all this friggin salt off the roads, I should be big HP 914'ing in no time. (IMG:http://www.914world.com/bbs2/html/emoticons/boldblue.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/beerchug.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/monkeydance.gif)

[Andyrew]

I didnt do that either... woops..

"But no one told me!"

betta get that done before wcc...

Thanks for the post! Glad it was fixed.

[BMartin914]

A friends tail shifter did the same thing. He swapped it out with a sideshift and now has no problem. Led us to conclude that the trans was where the problem was at.

[neo914-6]

Chris,
Correct me if I'm wrong but did John install a high hp engine with the stock 901? I was impressed how it held up. What KEP clutch are you running now?

[aircooledboy]

Yes, the old boy is sporting a rear wheel dyno of 410 hp. I have been well behaved off the start with the 901, and John was too (most of the time (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) ). I don't baby it, but I don't beat it either. When Brad had it open to do the gear swap he found it to be pefect inside. So I would say it is holding up very well. I upgraded the new p plate from a Stage II KEP to a Stage III, and I am going to use a stock 228mm Sachs disk. (IMG:http://www.914world.com/bbs2/html/emoticons/boldblue.gif) The stage II I pulled out showed strong signs it just couldn't hold the hp. (IMG:http://www.914world.com/bbs2/html/emoticons/unsure.gif)