2D Options - Repair or Upgrade?

Dockmaster said:
Is second gear in the Fortin H pattern different than in the sequential? Or suspect in both?
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Smaller. So wears faster. 
Kevin McMullen put both gears side by side for me and there is a substantial difference in width. 

 
As a genwral rule... I wonder what makes the bigger difference... the width of a gear or the diam/depth of the teeth (or both) 

Also, how does the ratio of the gear affect lifetime?  Will a 5.11 gear last longer or shorter than a 3.08?  (Or whatever mendi sand car ratios actually apply...)

Does the previous question apply to ring and pinions the same as say 3rd gear in a 2D?

Did I shoot myself in the foot going to a steeper R&P to get it into 3rd more than 2nd?

@Sean@Weddle..

 
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Bobalos said:
As a genwral rule... I wonder what makes the bigger difference... the width of a gear or the diam/depth of the teeth (or both) 

Also, how does the ratio of the gear affect lifetime?  Will a 5.11 gear last longer or shorter than a 3.08?  (Or whatever mendi sand car ratios actually apply...)

Does the previous question apply to ring and pinions the same as say 3rd gear in a 2D?

Did I shoot myself in the foot going to a steeper R&P to get it into 3rd more than 2nd?

@Sean@Weddle..
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Another set of questions that probably deserves it's own post, but I'll make quick answers here:

Width vs. depth (shaft center distance): Generally, bigger shaft centers will create a stronger gear, allowing for larger tooth profiles in lower ratio gears. Space requirements do not always allow for big shaft centers. 

Gear ratio lifetime: The lower the ratio, the driving gear has to turn the driven gear over more often, so the teeth on the driving gear see more use (example: a 3.09 1st gear, the driving gear turns 3.09 times for every 1 turn of the driven gear). The bigger effect is how much use that particular gear is subjected to. 2nd and 3rd gear wear out fast simply because they are used the most.

R&P's wear at a different rate than 1st-4th gears for a variety of reasons, the biggest being that the R&P is always driving under load in any gear. But, since the gear teeth are much larger in size, they can somewhat even each other out over time.

A taller ratio R&P is stronger, and generally longer lasting because there are typically more teeth on the pinion head (see my comment above about a 3.09 1st gear wear life), but since the final drive ratio is higher, you need to compensate by running a lower ratio forward gearset (this is the Fortin conundrum, high ratio R&P for strength, lower/weaker ratio 2nd gear to compensate). 

A lower ratio R&P is weaker, but allows for a stronger, higher ratio forward gearset. The trick is find the happy medium, which I think we have the best options for with 4.63, 4.86, and 5.14 R&P's that allow for decently stronger 2nd and 3rd gears. 

 
thanks @Sean@Weddle, that helps quite a bit. 

I probably should have put this into my original post... I made the R&P change I did, because I was in 2nd all of the time & understood that 3rd was 'stronger' than 2nd & I did not have the TQ to do it in 3rd.  I figured a R&P change would help that.  While it has helped, Im still in 2nd quite a bit, Im up in 3rd a lot more, to spreading the love around.  the reason for the 2nd gear change was because it was wore out & the 1.93 was what he had. 

image.png

 
Anyone know approximate cost of a Fortin FRS4 Sequential? Can't seem to find anything current online. Looking to compare to an S4. Looks like it might fit with less work than an S4 so trying to get an idea if worth the extra cost for the Fortin vs. doing more work for an S4

 
Dockmaster said:
Anyone know approximate cost of a Fortin FRS4 Sequential? Can't seem to find anything current online. Looking to compare to an S4. Looks like it might fit with less work than an S4 so trying to get an idea if worth the extra cost for the Fortin vs. doing more work for an S4
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Give Kevin McMullen a call.  602-402-6215.

I'm betting around $16k?

 
I had a good chat with Mr. McMullen. He is a very knowledgeable individual and was kind enough to humor my stupid questions. The Fortin trans runs nearly 1.5x the cost of an S4. He said the S4 actually has a bit stronger gears and the R&P are comparable. Apparently the Fortin shifts a bit smoother. Lead time for an S4 is challenging whereas a Fortin would likely be quicker. He did say the S4's lead times do appear to be improving as apparently a bunch of parts recently arrived and will help to clear some of the backorders. More to ponder. 

 
For what it's worth, I am still telling people to expect about 6-months for a new S4/S5 trans, once a deposit is placed. There is a small chance that could improve over the next few months depending on us being able to keep up this level of production on parts. 

We are getting caught up and stocking up on many of the parts needed for these. It will get better this next year. 

 
Hoping to finally get some time to pull my trans this coming weekend. As I still ponder the repair or upgrade question I know I will have to decide on gear ratios if I upgrade. I currently have 31” tires. What benefit would I receive from going to say a 33” tire? Any reason to consider even bigger? My car is pretty small at around 12.5’ long so I think anything taller than a 33” would probably look silly. I’m not unhappy with the look and performance of the tires I have now so curious if worth even considering a change? The only performance challenge I have is the car starts to get a little squirrelly at high speeds but I’m rarely in that speed range. I’m talking like 90-100 mph. And I haven’t worked on that issue so no idea if tire size would have any effect on this issue regardless? 

 
Personally, I would rebuild the 2D, didn't you say it has 6 years on it??  I run a 2D in my Funco with a Honda 3.5 turbo (425hp), in 6 years not a single break of a gear.  It has been rebuilt twice for around $2k.  This last time is started to leak, and it need new seals.

 
Finally got time to pull the car out of the trailer and do some work yesterday. I put the car up on my lift to get it off the ground. With engine running, the trans is in reverse when should be in neutral. In any other gear location on the shifter when I let the clutch out it kills the engine. Put it back to neutral location and it's back in reverse. And when I say it kills the engine I mean like immediately. So even if it was stuck in 4th gear it wouldn't do this with the car up in the air. I also disconnected the shift linkage at the trans and tried to shift it there. Same issue, reverse or kills the motor. 

After this test I drained the oil. I didn't get any chunks out the drain hole but the oil looks like someone put lots of fine metallic glitter in it. And this was new oil before this last trip. 

Spent the rest of the afternoon pulling the trans. I plan to take it to Marks Sandtrans in my area for teardown and diagnosis. 

 
Fine glitter might be bearing material.

I have had that when my pinion head bearing let go.

 
Dockmaster said:
Finally got time to pull the car out of the trailer and do some work yesterday. I put the car up on my lift to get it off the ground. With engine running, the trans is in reverse when should be in neutral. In any other gear location on the shifter when I let the clutch out it kills the engine. Put it back to neutral location and it's back in reverse. And when I say it kills the engine I mean like immediately. So even if it was stuck in 4th gear it wouldn't do this with the car up in the air. I also disconnected the shift linkage at the trans and tried to shift it there. Same issue, reverse or kills the motor. 

After this test I drained the oil. I didn't get any chunks out the drain hole but the oil looks like someone put lots of fine metallic glitter in it. And this was new oil before this last trip. 

Spent the rest of the afternoon pulling the trans. I plan to take it to Marks Sandtrans in my area for teardown and diagnosis. 
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Kraut_n_Rice said:
Sounds like the reverse idler is stuck in position. 
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This is the likely cause. Reverse idler gear could have slipped out of the pin that throws it back and forth to engage into reverse with the 1-2 slider, and is now "floating" between 1st/2nd gears, and caught/engaged on the 1-2 slider which means it is engaged in reverse. Once you shift into other gears, it would be engaged in 2 gears at the same time, and therefore lock up the trans. 

Pictures attached for visual fun. (I don't know why they are rotated 90º, they are straight on my computer)

IMG_0686.jpg

IMG_0689.jpg

 
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Trans was finally torn down and inspected. 1-3 gears are toast as well as reverse. The reverse gear pin also broke which is what caused the issue I was having. There is also a crack in the case. My trans guy says the case crack is in a typical spot. Some guys continue to run them with this crack, others do not. Crack is visible in second picture. R&P has typical wear but he says it is still good to re-use. My thoughts are to go ahead and re-build the 2D and use it while I shop for a s4 or s5 and then do an upgrade if I can find one for a decent price. 

Gear Stack.jpg

Case Crack.jpg

Reverse.jpg

R&P.jpg

 
Switching from a 2d to an S4 was one of the best things I ever did. It is well worth it.

 
put the 2d together use the car and do the up grade as a summertime project if you still worried about reliability. you will still be able to sell that trans for more than the cost of the repair and if you order a s4 you not going to see it till the middle of the summer. there are alot of other upgrades  you will be doing   if you do the up grade axels cvs moving mounts possible motor mounts trans mounts shifter. to be honest if your going to keep running small tires i would just keep the 2d they are a strong trans even tho you are at 510 hp the smaller tires should help a bit. 

 
I plan to have the 2D rebuilt and install it, I gave the shop the green light to rebuild it. I'll start shopping for parts and info to do an upgrade to an S4 as time allows. If the 2D would have had a single point failure or some unusual thing happen that caused the issue I might opt to keep the 2D. But given the extent of issues it's clear to me it is not holding up in my application. I don't think my car has 2,000 miles on it since new so it's not like this trans is seeing much use. I don't get a lot of opportunity to use my car so when I do, I want it to hold up. I would rather spend the $$ on an upgrade than worry every time I hear a little noise and wondering if the trans is about to go. The upgrade should help resell and value when the time comes to sell as well. 

 
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