lengel's TIII Omni GLH progress (used to be spirit r/t)

[135sohc]

Chrysler/new process figured out the straight roller and ball bearing combination wasn't so great during later versions behind the diesel engine in the export minivans.

[BadAssPerformance]

The bearing bulkhead plate is listed in the parts manual as its own part number and the service manual says it can be changed independently of the case. The differential cover is what cannot be changed as those are machine matched to the case at the time of manufacture.

True story. I swapped bearing plates on my last trans a couple times, once without setting input shaft preload

Yes this is why i want to incorporate the bearing backing plate into the bearing support plate over the input shaft. Doing this you will have to modify/cut the bearing backing plate, and only use the three bolt around the intermediate shaft. My thought is doing this will eliminate all the load from the input shaft going into those 4 bolts.

Making the whole bearing plate out of 4140 will do most of the work. Think of it this way, even if the shaft pushed on the stock backing plate, the aluminum plate is flexing enough to crack. If the aluminum plate is 4140, it will not flex nearly as much and wont crack. Do you have access to a HT oven large enough to fit the plate? Could make it really strong, LOL

[lengel]

Well, bearings options are not great, try sourcing a proper one one these days for the driver side without getting one of the few remaining at dealerships. I wondered if a tapered bearing that requires shimming could be used when the plate is completely replaced. Bearings that wont also go defunct a few years from now would be awesome. I kinda figured you could easily create different sleeves for the intermediate shaft that allows fitment of various ID bearings and then the plate could be machined for that bearing. Same on the driver side except the case hole would be a seperate mod if not matched up.

I like the idea of using a standard bearing that is cheap and available, but I don't think two tapered rollers on each side of the intermediate shaft is the best idea. That would cause a huge load on the passenger side of the case. If I turned it into a 4speed I have some ideas to use tapered rollers, but I'm not ready to give up 5th gear yet.

Chrysler/new process figured out the straight roller and ball bearing combination wasn't so great during later versions behind the diesel engine in the export minivans.

Do you now what type of bearing they use? Any pictures? Do you now the model of transmission used?

True story. I swapped bearing plates on my last trans a couple times, once without setting input shaft preload



Making the whole bearing plate out of 4140 will do most of the work. Think of it this way, even if the shaft pushed on the stock backing plate, the aluminum plate is flexing enough to crack. If the aluminum plate is 4140, it will not flex nearly as much and wont crack. Do you have access to a HT oven large enough to fit the plate? Could make it really strong, LOL

Well it's not going to be 4140 I can't find a piece that big, and if I could I think it would be out of my price range. I think I'm going to use 1018 steel or 7075 aluminum. They both have similar yield strength. Thoughts?

I see what your saying. My thought is the input shaft may still flex the thin steel backing plate. I only see three dead back to integrating in to the support plate.
1- A thicker piece a stock will be needed to start with
2- A little more machine time
3- The bearing backing plate will need to be modified.
All these draw backs I am willing to sacrifice for a stronger part.

[acannell]

I like the idea of using a standard bearing that is cheap and available, but I don't think two tapered rollers on each side of the intermediate shaft is the best idea. That would cause a huge load on the passenger side of the case. If I turned it into a 4speed I have some ideas to use tapered rollers, but I'm not ready to give up 5th gear yet.



Do you now what type of bearing they use? Any pictures? Do you now the model of transmission used?



Well it's not going to be 4140 I can't find a piece that big, and if I could I think it would be out of my price range. I think I'm going to use 1018 steel or 7075 aluminum. They both have similar yield strength. Thoughts?

I see what your saying. My thought is the input shaft may still flex the thin steel backing plate. I only see three dead back to integrating in to the support plate.
1- A thicker piece a stock will be needed to start with
2- A little more machine time
3- The bearing backing plate will need to be modified.
All these draw backs I am willing to sacrifice for a stronger part.

As far as 4140. Try checking out this guys ebay auctions:

http://www.ebay.com/itm/11-Inch-diam...item27f6339b68

I think a 11 or 12 inch diameter circle would fit the bearing plate would it not?

That one is annealed, and 2 1/4" long, for only $75 shipped. So you could get what like 4 or 5 bearing plates out of it? Or just bandsaw the chunk off you need and sell the rest, and you get your piece probably for free!

He has a lot of very large diameter drops of various thicknesses and materials. I betcha he could hook you up with something. Maybe message him and tell him what you want.

This is sort of like the axle crack issue. What material parameters have the biggest impact on preventing cracks? Yield strength? Stiffness? Surface finish? Geometry? Dunno..if you can find just one automotive white paper or something showing how someone reduced a bearing plate cracking issue, I'd follow that lead as far as picking a material. No matter what you make it out of I cant see it costing you more than $50 in stock.

[lengel]

As far as 4140. Try checking out this guys ebay auctions:

http://www.ebay.com/itm/11-Inch-diam...item27f6339b68

I think a 11 or 12 inch diameter circle would fit the bearing plate would it not?

That one is annealed, and 2 1/4" long, for only $75 shipped. So you could get what like 4 or 5 bearing plates out of it? Or just bandsaw the chunk off you need and sell the rest, and you get your piece probably for free!

He has a lot of very large diameter drops of various thicknesses and materials. I betcha he could hook you up with something. Maybe message him and tell him what you want.

This is sort of like the axle crack issue. What material parameters have the biggest impact on preventing cracks? Yield strength? Stiffness? Surface finish? Geometry? Dunno..if you can find just one automotive white paper or something showing how someone reduced a bearing plate cracking issue, I'd follow that lead as far as picking a material. No matter what you make it out of I cant see it costing you more than $50 in stock.

Stupid me didn't think of using round! Thanks! 10"diameter is close and 11" will work perfect. Total stock thickness will need to be 1.125. I still may want to use 7075 if it will be strong enough, just because of the weight savings. Maybe some of the engineering folks will chime in on there thoughts of 4140 vs 7075 in this application.

[135sohc]

Adam check this out: Diesel transmission thread

[cordes]

Stupid me didn't think of using round! Thanks! 10"diameter is close and 11" will work perfect. Total stock thickness will need to be 1.125. I still may want to use 7075 if it will be strong enough, just because of the weight savings. Maybe some of the engineering folks will chime in on there thoughts of 4140 vs 7075 in this application.

I would go with the steel due to the higher strength to volume. There already isn't much room between the trans and the tire. If you push that out further you're going to diminish your ability to turn right.

[lengel]

Adam check this out: Diesel transmission thread

Wow how did i miss that thread! I love the idea of using off the self tapered rollers on the intermediate shaft, but I feel doing so will introduce a huge axial load on the pinion side of the case on launch.

I would go with the steel due to the higher strength to volume. There already isn't much room between the trans and the tire. If you push that out further you're going to diminish your ability to turn right.

Yeah im kinda leaning toward to a steel plate as well. The extra thick stock is needed just for the purpose of integrating the backing plate into the support plate. This will be under the end cover, and not add any length to the trans.

[BadAssPerformance]

Well it's not going to be 4140 I can't find a piece that big, and if I could I think it would be out of my price range. I think I'm going to use 1018 steel or 7075 aluminum. They both have similar yield strength. Thoughts?

I see what your saying. My thought is the input shaft may still flex the thin steel backing plate. I only see three dead back to integrating in to the support plate.
1- A thicker piece a stock will be needed to start with
2- A little more machine time
3- The bearing backing plate will need to be modified.
All these draw backs I am willing to sacrifice for a stronger part.

I would go steel 4140 or 4340 if possible, or even 1050. Steel works more like a spring than aluminum so even if it does flex, there are more cycles before fatigue

With that said, the OE part is die cast so a machined aluminum will be stronger, but fatigue is still a concern.

In steel or Al, adding material wherever you can and combining the backing plate will help. Even where the web (middle portion of the plate) connects to the outer perimeter, huge radius and/or added thickness. Maybe if you get it modeled up we can run some shaft loads into it in FEA?

[cordes]

Reaper posted a link to some site a few years back and I read through it. It was a great read regarding bearing type and how the gears were cut too. I would agree that a tapered bearing on the main shaft would induce a great amount of force axially. I wouldn't want to see how the end plate would need to be braced up in order to offset that. At the same time I know a lot of guys want to go with straight cut gears. That would reduce quite a bit of the axial load put on the shafts by the helical cut gears. IMO coupling straight cut gears with a tapered bearing would come out closest to being a wash in terms of the axial force and be better on both ends.

Perhaps some A-MEs (Armchair Mechanical Engineer) could chime in with their thoughts.

[BadAssPerformance]

Axial force is from the helical gears so full straight cut gears solves most of the issues even would work with stock bearings. At that point the only axial load is from shift fork and you'll break a shift fork before a bearing or plate.

[Ondonti]

Reaper posted a link to some site a few years back and I read through it. It was a great read regarding bearing type and how the gears were cut too. I would agree that a tapered bearing on the main shaft would induce a great amount of force axially. I wouldn't want to see how the end plate would need to be braced up in order to offset that. At the same time I know a lot of guys want to go with straight cut gears. That would reduce quite a bit of the axial load put on the shafts by the helical cut gears. IMO coupling straight cut gears with a tapered bearing would come out closest to being a wash in terms of the axial force and be better on both ends.

Perhaps some A-MEs (Armchair Mechanical Engineer) could chime in with their thoughts.

I don't particularly understand the difference between using a Tapered or the roller bearing on the driver side as the shaft is only walking one direction the whole time. On the passenger side, I don't get how it would be different except maybe with wheel hop (but worrying about that would mean the driver side is taking all the load with the ball bearing setup. Design a little bearing cup that sits into the passenger side and fastens through the bearing retainer holes. If there are bearings with smaller OD's that could still fit our shaft there are so many ways to go about saving our transmissions without case machine work. My transmission that had a sleeve nearly chew through the case might not be happy with an unsupported tapered bearing setup and some wheelhop.

[Reaper1]

I would go with steel because you stand a far less chance of cracking the plate again due to work hardening over time. Would it actually be a huge deal? Probably not, but why take the chance.

[lengel]

I would go steel 4140 or 4340 if possible, or even 1050. Steel works more like a spring than aluminum so even if it does flex, there are more cycles before fatigue

With that said, the OE part is die cast so a machined aluminum will be stronger, but fatigue is still a concern.

In steel or Al, adding material wherever you can and combining the backing plate will help. Even where the web (middle portion of the plate) connects to the outer perimeter, huge radius and/or added thickness. Maybe if you get it modeled up we can run some shaft loads into it in FEA?

Working on the solid model.

Reaper posted a link to some site a few years back and I read through it. It was a great read regarding bearing type and how the gears were cut too. I would agree that a tapered bearing on the main shaft would induce a great amount of force axially. I wouldn't want to see how the end plate would need to be braced up in order to offset that. At the same time I know a lot of guys want to go with straight cut gears. That would reduce quite a bit of the axial load put on the shafts by the helical cut gears. IMO coupling straight cut gears with a tapered bearing would come out closest to being a wash in terms of the axial force and be better on both ends.

Perhaps some A-MEs (Armchair Mechanical Engineer) could chime in with their thoughts.

With using tapered rollers it will put more load on the passenger side of the case not the end plate side. Straight cut gears would be awesome! Yes with straight cut gear tapered rollers on the intermediate shaft would be the way to go.

Axial force is from the helical gears so full straight cut gears solves most of the issues even would work with stock bearings. At that point the only axial load is from shift fork and you'll break a shift fork before a bearing or plate.

Yes they would be awesome, but Im not willing to spend the $5000+ on custom gear set. I think we have a strong gear set as is, we just need to keep the shafts from moving around. The next affordable step to making 568 stronger in my eyes is the steel support plate.

I don't particularly understand the difference between using a Tapered or the roller bearing on the driver side as the shaft is only walking one direction the whole time. On the passenger side, I don't get how it would be different except maybe with wheel hop (but worrying about that would mean the driver side is taking all the load with the ball bearing setup. Design a little bearing cup that sits into the passenger side and fastens through the bearing retainer holes. If there are bearings with smaller OD's that could still fit our shaft there are so many ways to go about saving our transmissions without case machine work. My transmission that had a sleeve nearly chew through the case might not be happy with an unsupported tapered bearing setup and some wheelhop.

Well to me the difference is with the stock roller bearing set up the whole main shaft is suspended from the bearing support plate, because of the snap ring on the outer race of the bearing. So all the axial load is on the support plate, and the force is toward the passenger side. Now using tapered rollers the intermediate shaft is sandwiched between the support plate and passenger side of the case, not suspended form the support plate. The axail force is still toward the passenger side, but it is no longer suspended. So now you have no load on the support plate, and all the load on the passenger side of the case. The case may be strong enough to take it, or it may not. I dont know. What I dont want to do is create a new problem.

I would go with steel because you stand a far less chance of cracking the plate again due to work hardening over time. Would it actually be a huge deal? Probably not, but why take the chance.

Thanks for the input! Sounds like steel is the consensus. Guess the only draw back is weight. Once i get it modeled ill see what the difference is.

[Ondonti]

Well to me the difference is with the stock roller bearing set up the whole main shaft is suspended from the bearing support plate, because of the snap ring on the outer race of the bearing. So all the axial load is on the support plate, and the force is toward the passenger side. Now using tapered rollers the intermediate shaft is sandwiched between the support plate and passenger side of the case, not suspended form the support plate. The axail force is still toward the passenger side, but it is no longer suspended. So now you have no load on the support plate, and all the load on the passenger side of the case. The case may be strong enough to take it, or it may not. I dont know. What I dont want to do is create a new problem.

This is what I am not getting. What is the difference between your use of the word "load" and "force"?
If the input shaft is taking all the force in FWD gears at the bracing on the engine side of the transmission, the other shaft will be putting all the stress on the bearing plate no matter what kind of bearings you have. Tapered bearings would just add some sort of preload on the case depending on how you shim it.

That is why I asked if wheelhop was a problem because wheelhop would put loads back and forth on the two tapered bearings.

[lengel]

This is what I am not getting. What is the difference between your use of the word "load" and "force"?
If the input shaft is taking all the force in FWD gears at the bracing on the engine side of the transmission, the other shaft will be putting all the stress on the bearing plate no matter what kind of bearings you have. Tapered bearings would just add some sort of preload on the case depending on how you shim it.

That is why I asked if wheelhop was a problem because wheelhop would put loads back and forth on the two tapered bearings.

Haha sorry load, and force same thing. I may be wrong, but I think you have backwards. Input shaft force is toward the diver side(support plate), and intermediate shaft force is toward the passenger side.

[turboshad]

I would personally go with steel. I feel it is a bending problem more than a yield problem and all steels have the same general modulus of elasticity, just different yield points. Many times chromoly is used more as a marketing tool as the general public sees it as be superior without really understanding the problem. I agree that you should stick to straight bearings if you can as the passenger side isn't designed very strong axially. That being said I can't remember which direction the gear angle goes as you will only be loading one or the other side......unless you drive in reverse like JT does to break trannys. With a tapered set though, any axial deflection will also decrease preload and could introduce gear separation. Possible this is why straight bearings were used in the first place as the intermediate shaft has a tapered set on each side of it on the input shaft and diff. Just a thought.

If you want anything run through FEA or a deflection comparison done between the AL and steel just let me know Adam.

[acannell]

That is why I asked if wheelhop was a problem because wheelhop would put loads back and forth on the two tapered bearings.

I'm liking this as a failure mode. At first I thought it made sense...1st gear is a torque multiplication of 12 roughly, the gear teeth are at 45 degree angles so that transmits half the force axially (?). So if the engine is outputting 100ftlbs at launch during wheel hop, you have a 600lb hammer whacking the bearing case at what 4 times a second for 3 to 5 seconds? Ouch.

But now that I think about it, the multiplication is not 12 to one because the ring and pinion arent in the game yet. So its more like 3 to 1 at most (which bearing pocket cracks? the input or int shaft? Which would put it at more like 150 lbs of force. And I'm not sure if 50% of the torque is really transmitted axially. Also, its not really like a hammer per se..its periodic but there are tires and suspension making it less of a "step" impact.

So what is cracking the bearing plate? Maybe its heat expansion reducing bearing clearance negative? Or maybe high torque is distorting the race and causing forces to focus in one spot or another?

[acannell]

I would personally go with steel. I feel it is a bending problem more than a yield problem and all steels have the same general modulus of elasticity, just different yield points. Many times chromoly is used more as a marketing tool as the general public sees it as be superior without really understanding the problem. I agree that you should stick to straight bearings if you can as the passenger side isn't designed very strong axially. That being said I can't remember which direction the gear angle goes as you will only be loading one or the other side......unless you drive in reverse like JT does to break trannys. With a tapered set though, any axial deflection will also decrease preload and could introduce gear separation. Possible this is why straight bearings were used in the first place as the intermediate shaft has a tapered set on each side of it on the input shaft and diff. Just a thought.

If you want anything run through FEA or a deflection comparison done between the AL and steel just let me know Adam.

Excellent analysis.

[Reaper1]

It's just the example he pulled the picture from...not a direct comparison to our transmission. It also depends on which way the shafts are spinning.

I don't know if this will work for everybody, but this looks like it's something out of a textbook and has force directions shown.

http://www.google.com/url?sa=t&rct=j...83829542,d.aWw