svp928

Errka, I think 5th just joins the mainshaft together without any gears involved, so power goes straight thru from input gear to pinion....but, I could be wrong...

Mike Simard

Yes, 5th gear is simply the input shaft meshed to the main shaft. There are no actual 5th gear teeth.
Given the symptoms, it must be either the teeth sheared off the input shaft and/or it's mating countershaft gear, or the entire counter cluster is laying in the box from the pin shaft falling out or breaking.

IcemanG17

sounds like the layshaft for sure.......

James Bailey

Pet is somewhat misleading when you look at 5 th gear it has gears on it but those gears transfer power to the layshaft. In all gears but 5 th the gearsets on the layshaft transfer power BACK to the pinion shaft. When in 5 th the input/ 5th gear is simply driving the pinion shaft on which it rides. Which means LESS mechanical loss in 5th which is a good thing

mark kibort

Yep, you guys are probably right. so, 5th was perfectly fine, as far as driving. I could have driven home !!!! might have burned up the clutch though, but probably not. but as Jim and the rest of the gang said, "5th" doesnt drive anything, but what comes out the rear end, into the diff. so, thats why 5th is fine. Is this a common failure? I dont know. I have broken 5th on the dyno at the coupler , which was not good, but it was because I got to experience the borg warner stuff with my '84 car.

anyway, 5th is toast. the gear is a mess, not missing any teeth, but they are all ground down and pretty chipped up. it looks like the mouth of a prize fighter.
I cant see much down deep, but the gear that meets 5th (is this the lay shaft?) is banged up too. BUT, all the other gears on top of the gear box, are perfect. no flaws at all. who knows what lurks below.

so, is it worth getting 5th gear and rebuilding (and the gear that matches 5th ?) or is it all completely junk. everything was so perfect, right up until the 4th gear, "Ziiiiiiiingggggg". If the top gears are perfect, wouldnt the bottom gears be too? sure, it will be expensive, and a lot of work, but heck, its the holbert transmission!! if it is only 5th gear for $1500 and a couple of extra parts, it still is a nice gear box, right? LSD!!

Thanks for the help on this project!

Many thanks to Bill Ball, who is nothing less than just a Saint! Thanks Bill. awesome to see you and hang out while wrenching on the 928. I owe you. If you need anything, you know who to call!

Mark

IcemanG17

Great news.....now you can come up March 5-6 to "coach" the "three musketeers" again!!!! This time it will be easier with your 928 on the track too!!!

Sean will be there starting on Thu the 3rd and I'm coming up on Friday the 4th..

I'll bring my Go-Pro and maybe we can set your racer up as the "camera car" to get some good footage of the others...until you get bored by our pace and take off!!!

mark kibort

Did I say "Thanks" to Bill Ball???

I cant believe the car is running again with a new transmission! all set. all bolts tightened, just have to buy more header bolts, as all of them were busted or stripped on removal.
Oh, and I need a rear CV joint bolt. and I need to torque them too. dont let me forget before I drive it. we had to cut a bolt off that had no chance of coming out of the transmission drive plate. nothing like a 4.5" cut off wheel!

mark kibort

hmmmm. 4th and 5th sounds good. Let me see if I can get Luc to let me instruct with the NCRC guys.
Ill write him an email now.
mark

IcemanG17

I forgot......

BILL IS THE MAN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Bill Ball

And don't forget to put some fluid in the tranny too!

All-in-all, a pretty smooth transplant.

Mike Simard

Rats, I wanted to ask you to look at the torque tube bearing but you worked fast! I have a theory about this gear failing and a way to prevent it that I'm doing to my car right now.
You didn't happen to look into the TT and see where the bearing was, did you?

mark kibort

yeah, we got a good look at the bearings. they spun a little too freely for Bills taste, but said it was quite normal. absolutely no play radially or axially. very tight. slight bearing noise when spun. when we started the car, and ran it. (no gear oil! ahhhh I forgot and hope we didnt damage anything for the min we ran it)
it was quiet as a mouse. no sound. all the sound was the transmission gear radiating through the torque tube and amplified by the bell housing. sounded like it was coming from the clutch!! I should have video taped the sound running. anyway, its all done!
oh, the bearing was about 12- 8" from the front and rear shafts

Bill Ball

The rear TT bearing was about 12 inches in (so probably not migrated much if at all). The front was about 8 inches, so it migrated forward a bit. As Mark said, the shaft spun true and had no play. The bearings sounded and felt dry to me when the shaft was spun. They did not need to be urgently changed, but this would have been the time to do it. However, since it is pretty easy to drop the TT on a 5-speed, Mark elected to do it at a later time.

Mark took some pictures of tranny inards. The end of the input shaft was fine, so, yes, the TT splines were good. There were lots of broken teeth visible on the input shaft (5th) gear and some on its mate below. That's all we could see. Everything else looked good. Perhaps the tranny could be rebuilt with just new 5th gear set. Not sure of that or their availability/cost. The replacement tranny looked pristine.

Rob Edwards

5th gear for a GTS is 'only' about $700 , dunno which flavor box Mark's is. G28/??

mark kibort

Ill post pictures tonight.

I would think, if none of the other gears are touched by the mayhem, all this will need is a new 5th, but who knows what lurks below!