New Tremec transmission

[Gaz64]

Here is a video:

https://www.youtube.com/watch?v=8YBeFZzv83Y&t=1815s

At 20:21 is where Paul is removing the 5th/rev shaft.

[RockBit]

Originally Posted by Gaz64

Here is a video:

https://www.youtube.com/watch?v=8YBeFZzv83Y&t=1815s

At 20:21 is where Paul is removing the 5th/rev shaft.

Really nice video.

My TKO600 shifts well, but I don't do a lot of speed shifting. One thing I noticed in the video is there is a reverse lockout for shifting out of 5th gear. My unit does not seem to have this feature. I have to be careful when downshifting from 5th to 4th to not go into reverse. Does anyone else have this issue?

[FredG]

I have watched every video that Paul has done. Very impressive. I was a little dismayed during one of his videos where he stated he will work on them but he doesn't like or sell Tremecs.

Fred

Originally Posted by Gaz64

Here is a video:

https://www.youtube.com/watch?v=8YBeFZzv83Y&t=1815s

At 20:21 is where Paul is removing the 5th/rev shaft.

[hauss]

Yep that is the rail, minis all the work it took to get to that point, also let us not forget we still have to get it back in the car.I have done this procedure 3 times already, in 8k miles. Mr. Esschaider; anyone who has done this one time would gladly spend $200 dollars for a rail that worked. I certainly know I would.I am a retired guy with more time than money and still I would. the $100 would only go to the first 10 people.

[eschaider]

Originally Posted by hauss

Yep that is the rail, minis all the work it took to get to that point, also let us not forget we still have to get it back in the car.I have done this procedure 3 times already, in 8k miles. Mr. Esschaider; anyone who has done this one time would gladly spend $200 dollars for a rail that worked. I certainly know I would.I am a retired guy with more time than money and still I would. the $100 would only go to the first 10 people.

Hauss, in as much as you have already done the market research, determined market size and buyer willingness to purchase at a particular price point, it appears all that is left to take advantage of this excellent business opportunity is for you to contract for the manufacture of these replacement parts and profit handsomely from the sales. I think you should do this sooner rather than later. This could change your personal situation into one of a retired guy now with more money than time.



Ed

[Gaz64]

Ed,

I think you are confusing 2 shafts.

One is the reverse idler shaft, which is a captive shaft for the reverse idler to spin on. The other is the 5th/Rev rail, which is the the rail that has broken in Hauss's case.

I do find it hard to believe how that rail breaks, and yet the roller pin small diameter should fracture first.

[patrickt]

Originally Posted by Gaz64

Ed,

I think you are confusing 2 shafts.

Yep, the original from 1971 was the best. You know, the first one with Richard Roundtree.

[NROTOXIN]

Originally Posted by patrickt

Yep, the original from 1971 was the best. You know, the first one with Richard Roundtree.

He's a bad mother.....shut yo mouth!

[eschaider]

Originally Posted by Gaz64

Ed,

I think you are confusing 2 shafts.

One is the reverse idler shaft, which is a captive shaft for the reverse idler to spin on. The other is the 5th/Rev rail, which is the the rail that has broken in Hauss's case.

I do find it hard to believe how that rail breaks, and yet the roller pin small diameter should fracture first.

You are correct about the two being different parts, Gary but I thought Hauss was describing the reverse idler shaft in his post #102 when he showed this pic of a new and a broken shaft;


The identifier I was using was the roll pin hole in the end of the shaft. It appeared that the shaft was the shaft pictured in Paul's video at time = 35:43 and in the Tremec manual in the image below;



Actually I am relatively agnostic with respect to naming conventions other than for identification purposes as long as they are somewhat representative.

Edit out: The reverse idler shaft apparently experiences an in service forward thrust, which Tremec attempts to blunt as can be seen by the presence of the reverse idler gear thrust washer in the Tremec service manual illustration. The direction of the thrust, if it were great enough, could certainly break the back side of the roll pin hole off the end of the shaft as Hauss has illustrated in his picture in post #102.

Looking at the assembled component I must admit I am struggling with trying to understand where the forward thrust that fractures the end of that shaft is originating from. That said, it is apparent from their use of a thrust washer and Hauss's success in repeatedly breaking the part that the thrust is real and does come from somewhere.>

Edit in: That thrust washer goes inside the main case not outside, which makes more sense. The helix on the gear would push the gear rearward not forward and a thrust washer inside the case would protect the case from the rearward thrust on the gear. That really leaves me at a loss to explain the failure.

The fact remains however, that fourth gear tops out even with a 3.46 (or thereabouts) rear gear set at nearly 200 mph (with 295 tires) which still begs the question, why are we power shifting into fifth gear overdrive down in the second or third gear vehicle speed range? That sort of operation does not seem to either be a smart or a competitive way to drive the car — and could likely be a contributing factor to the repeated component failures Hauss's transmission is experiencing.


Ed

[Gaz64]

The photo above of Hauss's broken 5th/rev rail shows 2 pieces at the fracture point. The roll pin secures the roller that follows the selector lever.

About 20:20 in the video.

Gary

[eschaider]

Thanks, Gary. As we watch Paul's assembly of the reverse idler shaft something jumped out at me. Tremec machines a relief in the main case for the dowel pin that is used to limit the forward movement of the shaft. The relief is adequate to allow the tailshaft to be assembled to the main case without interference with the dowel.

If the reverse idler shaft is modified to use a snap ring the case will need to be machined to provide a relief for the snapring to register in so it does not prevent the tail shaft from fully seating against the rear face of the main case. In actual fact you would probable want to machine the main case to accept a hardened washer that would fit between the snap ring and the main case.

The reason I an suggesting the washer is that a snap ring only has a small shoulder that would stand proud of the reverse idler shaft. We already have a shaft that is being forced forward with enough force to break the end of the idler shaft. With just a snap ring and no larger diameter washer to spread the force over, I suspect the snap ring would be mushed into the aluminum backside of the main case.

That means a second machining operation, this time on the main case, to accommodate a thrust washer. Not impossible to do but the mod has just taken a significant step up in complexity and potential transmission main case damage if not done correctly.

Discretion may be the better part of valor here. My car has 295 tires in the back and at 7000 rpm in fourth gear is a whisker north of 191 mph! I (fortunately) lack the poor judgement to tempt disaster by running it that high in fourth before shifting into fifth, In the real world it would appear that if you could not beat the car next to you before the end of second gear let alone fourth gear, (assuming you have not crashed yet) a power shift into fifth gear is not going to improve the situation .

This particular component failure begs the question why are we power shifting into over drive at lower speeds where fourth gear is the better gear to be in. Even with the stock 3.46 ring and pinion my car was delivered with, 4th gear is good to well over 160 mph! Frankly at anything significantly over 100 mph or so in these cars require a steely spine and stunningly good driving skills not to mention a good dose of bad judgement.


Ed

[hauss]

Sounds good Ed. Shall I put you down as the first in line?Oops 2nd,Ill be the first only 8 more to go!

[eschaider]

Originally Posted by hauss

Sounds good Ed. Shall I put you down as the first in line?Oops 2nd,Ill be the first only 8 more to go!

Actually I don't power shift fifth gear at any speed, let alone low speed and significantly have never broken even one reverse idle shaft sooo, I'm probably not a prime candidate for a replacement piece.


Ed

[hauss]

FyI. you cannot buy the rails from hanlon or silversport they are all sold out. Not sure what to think.Found one on ebay $50 shipped to my house.

[eschaider]

That makes more sense, Gary. Until you raised the one part two pieces after breaking alternative, I was viewing the picture as an image of two parts, one good shaft and one broken shaft. The length of the misidentified 'good part' and location of the dowel pin hole was leading me to believe it was the reverse idler gear shaft.

When you look at it as a broken fifth and reverse shift rail that fractured at the selector link pin hole, then Hauss's early pic and the method of failure makes sense. Thanks for the wake up call.


Ed

[eschaider]

I was thinking something very similar, Anthony. I am not sure of the exact mechanics of the failure but if it occurs because of force applied to the shaft by the pin then reducing hole diameter for a stronger shaft would sound like a good compromise. Somewhere (I don't know where) the reduced pin diameter might begin to produce pin failures where the head of the pin is being sheard off.

Bottom line, I think the 5th gear overdrive design was never intended for use in a power-shifted environment. Just not power-shifting into 5th overdrive might be the easiest and most straight forward fix for the problem. Moreover, if you haven't won the contest before 5th gear overdrive, I am not persuaded that 5th gear will make a difference in the outcome anyhow.


Ed

[Anthony]

Originally Posted by eschaider

Bottom line, I think the 5th gear overdrive design was never intended for use in a power-shifted environment. Just not power-shifting into 5th overdrive might be the easiest and most straight forward fix for the problem. Moreover, if you haven't won the contest before 5th gear overdrive, I am not persuaded that 5th gear will make a difference in the outcome anyhow.
Ed

Well, from reading some of the posts, maybe it's not powershifting into 5th, so much as "power" shifting from 2nd to 3rd, and somehow hitting 5th gear instead, putting stress on the 5th gear shaft ?

[eschaider]

Originally Posted by Anthony

Well, from reading some of the posts, maybe it's not powershifting into 5th, so much as "power" shifting from 2nd to 3rd, and somehow hitting 5th gear instead, putting stress on the 5th gear shaft ?

I am sure that would not be good for the transmission but I got the impression from Hauss's commentary that he was power shifting 5th gear from 4th gear, when these failures occurred.


Ed

[hauss]

Originally Posted by eschaider

I am sure that would not be good for the transmission but I got the impression from Hauss's commentary that he was power shifting 5th gear from 4th gear, when these failures occurred.


Ed

Not sure why you guys are going off the rails but let me try to clarify what is going on. 1st off to me power shifting means no clutch this is not the case.Heavy throttle in 4th using clutch to shift to 5th and rail breaks around 5500 rpm. new rail will eliminate roll pin adding more material to shaft {no 2nd hole drilled for roll pin.} making it stronger. same design on the new TKX holding the finger to the shaft.the new rail will share features but will not be the same as the TKX so there will be no patent violations. Tremec or silversport or liberty gears should have already done this!

[Gaz64]

Originally Posted by Anthony

Well, from reading some of the posts, maybe it's not powershifting into 5th, so much as "power" shifting from 2nd to 3rd, and somehow hitting 5th gear instead, putting stress on the 5th gear shaft ?

This sounds like the cause.

Any more info about how this happens Hauss?