I had a guy email me about what I would charge to do the 3.09 final drive swap and ship him the transmission once done. Here is a rough breakdown of costs. Like I said earlier, this isn't an inexpensive upgrade.
$1100 - zero mile MT2 F40. $950 - 3.09 F40 purchased in the UK and shipped to the US $250 - new bearings for the main shafts, ARP bolts for differential, shims, and other supplies $500 - labor for the disassembly, machining of VSS boss and case for starter clearance, and reassembly $175 - shipping the hybrid 3.09 F40 to the customer
$2975 total and the lead time could be 3-6 weeks.
$1250 additional if you wanted a Quaife Limited Slip
My first trip was 287 miles at 75 mph and averaged 28 mpg. I want to do another one at 70 mph to see if I can't get over 30 (my 29 mpg with the other wheels and tires was at 70 mph) . The 235 and 285 tires certainly are not helping the mpg. My rear tires are 24.8" tall.
The next one I am going to bring the laptop and scan the drive. I want to make sure the timing in the lower RPM/higher load cells is where it needs to be.
I had a guy email me about what I would charge to do the 3.09 final drive swap and ship him the transmission once done. Here is a rough breakdown of costs. Like I said earlier, this isn't an inexpensive upgrade.
$1100 - zero mile MT2 F40. $950 - 3.09 F40 purchased in the UK and shipped to the US $250 - new bearings for the main shafts, ARP bolts for differential, shims, and other supplies $500 - labor for the disassembly, machining of VSS boss and case for starter clearance, and reassembly $175 - shipping the hybrid 3.09 F40 to the customer
$2975 total and the lead time could be 3-6 weeks.
$1250 additional if you wanted a Quaife Limited Slip
Now you are making me want to break my current F40 I already have a spare new F40.
Back when I had my Shop in Rockford, we disassembled 5 or 6 F40's to have the internals Cryo'ed.
I took part in disassembly of the first one, then Rob & Kris disassembled the rest of them.
So, the problem is old age, I can't recall how to unlock this mechanism. Can you let me know?
Archie 847-212-3909 or Archie@v8archie.com or just reply here.
Thanks a lot.
Archie
Edited to add....... I figured it out. It was the simplest thing in the whole teardown.
Thanks
Archie
quote
Originally posted by fieroguru:
Under the gear set removed by pry bars is a different locking mechanism. There is an outer ring holding two half moon pieces with a locking tab that fits into the hole.
[This message has been edited by Archie (edited 11-18-2020).]
Originally posted by Archie: So, the problem is old age, I can't recall how to unlock this mechanism. Can you let me know?
Archie
Once you have it disassembled this far, the only thing holding the next gear in place are the two C-clips that slide into a groove in the shaft. They slide right out and away from the shaft, then the gear can slide off.
Guru, you have said that 1st and 2nd gear ratios are a part of the shafts, I see the differential drive gear at the end of the shaft. But where is the input gear for the shaft? I assume it is the synchro gear,..correct? Could it be possible to change out those gear sets? My train of thought is a higher first and a lower second. I know I have mentioned this before and you gave an answer, but I still haven't understood why the first and second are permanent? Thanks for your patience with my questions.
A taller first is something a hairy problem. In reverse, power flows from the first input gear (input shaft) to the first output gear (lower output shaft) to the reverse gear (upper output shaft) to the final drive. The first output gear and reverse gear are permanently meshed. This allows reverse to the synchronized, since the reverse gear runs on the upper output shaft just like 3rd and 4th.
This means that for the first input to be larger and first output to be smaller (taller first), the reverse gear must grow as well. While there's always room to make a large gear smaller, and almost always room to make a small gear larger, having the space to make a large gear larger is not a foregone conclusion.
[This message has been edited by Will (edited 11-19-2020).]
Guru, you have said that 1st and 2nd gear ratios are a part of the shafts, I see the differential drive gear at the end of the shaft. But where is the input gear for the shaft? I assume it is the synchro gear,..correct? Could it be possible to change out those gear sets? My train of thought is a higher first and a lower second. I know I have mentioned this before and you gave an answer, but I still haven't understood why the first and second are permanent? Thanks for your patience with my questions.
The two shafts that this thread focused on are the Main Upper and Main Lower, which are also the two output shafts. These both have the pinion gear formed and cut into the actual shaft. We are fortunate in that GM offered several versions with different gear ratios. 3.091, 3.348, 3.545 (G6), 3.762, 3.895, 3.909, 4.176. Since the G6 version came with the 3.545, we have options for shorter and longer gears.
The shaft the clutch disk rides on is the input shaft and 1st and 2nd gear are formed into the shaft. Here is a drawing of what the input shaft looks like.
If only one gear had been formed into the input shaft, you would be able to change gear ratios independently... but that simply isn't the way GM did it, so we can only swap 1st and 2nd gears as a paired unit. There are 4 pairs from GM: 3.769/2.040 (G6), 3.917/2.040, 4.167/2.130, 4.167/2.190. Unfortunately, the G6 version has the longest first of the entire group, so there isn't any stock GM option for a longer 1st. Your only option would be have a custom input shaft and corresponding gears on the main shafts made.
As I mentioned in the other thread, fix the shortness of 1st with the final drive swap. Even with the "wider than ideal" 1-2 upshift, you will still be within 5 lb/ft from peak torque given the super flat torque curve of the LS4.
Cool thanks for the explanation. My next question is about the noise that people have complained about from the transmission. Do you know what it is and how to fix it?
Cool thanks for the explanation. My next question is about the noise that people have complained about from the transmission. Do you know what it is and how to fix it?
The rattle is from the gears on the shafts rocking back and forth with engine crankshaft pulsing. Keeping the camshaft stock (smooth idle) and using a dual mass flywheel (better crankshaft pulsing dampening) will make it better.
Mine is worse than most due to the camshaft, choppy idle and the 12lb flywheel. I have experimented with lots of transmission oil combos, but the way to completely stop the rattle is to press down on the clutch when idling. As you can hear in this video, I can make it rattle less or more as well as make it stop completely with motions of the clutch pedal.
My first trip was 287 miles at 75 mph and averaged 28 mpg. I want to do another one at 70 mph to see if I can't get over 30 (my 29 mpg with the other wheels and tires was at 70 mph) . The 235 and 285 tires certainly are not helping the mpg. My rear tires are 24.8" tall.
Would that be a 285/35-17? I'm quoting this in order to save searching time, and since it's a pretty important factor in the overall outcome. And because it's a possible work around to the trans gearing issue, or will there be not be enough wiggle to perform an adequate and practical change in tire height? Does a 28" tire bring the effective ratio down to similar to using a 3.09 final drive?
[This message has been edited by sourmash (edited 11-21-2020).]
Would that be a 285/35-17? I'm quoting this in order to save searching time, and since it's a pretty important factor in the overall outcome. And because it's a possible work around to the trans gearing issue, or will there be not be enough wiggle to perform an adequate and practical change in tire height? Does a 28" tire bring the effective ratio down to similar to using a 3.09 final drive?
Like I said earlier, my car is worse based on the choppy idle, 12 lb flywheel and I was intentionally making it rattle as hard as I could to show the different result in release technique. Don't assume every F40 sounds like mine, because they don't.
I run 285/30/18... on 9.5" wide rear wheels. On the 88s' you have to go to 18s for this width to clear the top of the knuckle attachment to the strut.
3.09 is a 13% reduction in final drive ratio. To get the same result with a diameter change, you would need tires 13% taller, which would be a 28" tall tire. If all you are looking at is cruise rpm, then this will work, but there are 5 pretty significant drawbacks to this method.
1. Increased wheel/tire combo weight will have an impact on acceleration beyond just the effective ratio change. 2. Sidewall flex from the taller tire/sidewall will make the cornering sloppy. Fix by running 20s and we go back to issue #1. 3. Reduces effectiveness of brakes. Contact patch is now 11% further from the wheel center which reduces the mechanical advantage of the brake calipers to stop the car. Fix with larger rotors which takes you back to #1. 4. Increased lateral loading on wheel bearings. Contact patch is 11% further from bearing center, so same lateral load induces an 11% larger bending moment on the wheel bearing flange as well as the bearing itself. This might be OK on a cruiser, but this would be a very bad idea for those that autocross and track the car as the bearings and flanges already have a shortened life. 5. Tire clearance reducing available suspension travel. With my 24.8" tires and current stance (about 1.5" lower than stock), I have barely kissed the wheel well liner. Making the tires radius 1.6" larger will limit available suspension travel and ride quality unless your goal is to have an off-road stance.
[This message has been edited by fieroguru (edited 11-21-2020).]
I think I'd be ok experimenting with tire sizes from about 26 to 27 inches for the cost differential. No, it's not an equivalent method. But it's as I said, a work around that someone might find beneficial to their cause. Importing a used F40 has risks, like getting an abused one.
I've had another car make with a nearly terrible 1st gear that had less ability to mess with tire sizing. Having to chase that Mustang GT down in 3rd could've been avoidable with an ability to change the final drive. I think they devised that ability later.
ADDED to avoid another post that nobody else might be interested in: I went back to see that Charlie64's wide body ran a rear Forgeline SP3P 19x11 with a 325/30-19 which was about 26.7" wheel. To me the car had too tall of a gear for the torque, but perhaps it was the unsprung weight? He posed that the wheel might weigh 27 lbs or so.
[This message has been edited by sourmash (edited 11-21-2020).]
The rattle is from the gears on the shafts rocking back and forth with engine crankshaft pulsing. Keeping the camshaft stock (smooth idle) and using a dual mass flywheel (better crankshaft pulsing dampening) will make it better.
Ok, now I am just benchtop racing, but just how loose are the tolerances on the shaft to make that much noise? Are the gear sets just floating on splines with crude snap rings holding them in a "general" location? If the same noise exists at operating temperature, then it goes without saying it isn't for expansion. Is there no fix? I assume that this noise will not decrease the life of the transmission? Will it get worse with time? And the question that everyone has asked, why would a manufacturer produce a product that sounds like it is already wore out?
Originally posted by Rickady88GT: ... And the question that everyone has asked, why would a manufacturer produce a product that sounds like it is already wore out?
Just my $.02.
This is not exactly a stock installation. No GM product with the F40 has a lumpy cam, like Paul's. Also, GM went to considerable expense to develop the dual mass flywheel that is normally supplied with this trans, with the 3.9 in the G6. Paul's installation has a more conventional flywheel/clutch setup. These are both conditions that this trans is normally not ever subjected to. When we mod our cars, we have to accept and understand the compromises that happen, when we "re-engineer" an installation, to suit a specific purpose.
Edit - removed a bunch of pointless babble...
[This message has been edited by Raydar (edited 11-21-2020).]
This is not exactly a stock installation. No GM product with the F40 has a lumpy cam, like Paul's. Also, GM went to considerable expense to develop the dual mass flywheel that is normally supplied with this trans, with the 3.9 in the G6. Paul's installation has a more conventional flywheel/clutch setup. These are both conditions that this trans is normally not ever subjected to. When we mod our cars, we have to accept and understand the compromises that happen, when we "re-engineer" an installation, to suit a specific purpose.
Edit - removed a bunch of pointless babble...
With a conventional clutch and flywheel, how much room is in the bell?
The rattle is from the gears on the shafts rocking back and forth with engine crankshaft pulsing. Keeping the camshaft stock (smooth idle) and using a dual mass flywheel (better crankshaft pulsing dampening) will make it better.
Mine is worse than most due to the camshaft, choppy idle and the 12lb flywheel. I have experimented with lots of transmission oil combos, but the way to completely stop the rattle is to press down on the clutch when idling. As you can hear in this video, I can make it rattle less or more as well as make it stop completely with motions of the clutch pedal.
I don't know if this would work in an F40 but it really helped with my gear rattle. I have a 3800 swap with a light flywheel in front of the Getrag 5 speed and it has the same annoying rattle at idle, kind of embarrassing sitting at stoplights in traffic. I worked my way through all the Red Line GL 4 gear oils, each one made a slight difference but even the with the 75W140 the rattle persisted. Against a Red Line tech's advice I put Heavy Shockproof in it and most of the rattle is gone and it actually shifts a bit better. I don't drive it in the winter but have driven it a couple of times with temps in the low 30s and it was a little bit stiffer, but not bad, until it warmed up. I only have about 1000 miles with the Shockproof and all is good so far, my research found that some Bimmer guys are running it for the same issue.
Originally posted by sourmash: ADDED to avoid another post that nobody else might be interested in: I went back to see that Charlie64's wide body ran a rear Forgeline SP3P 19x11 with a 325/30-19 which was about 26.7" wheel. To me the car had too tall of a gear for the torque, but perhaps it was the unsprung weight? He posed that the wheel might weigh 27 lbs or so.
His car is great, but it has large heavy wheels front/rear, heavy brakes, heavier body kit, heavy stereo with amps, aftermarket dash and door panels, aftermarket suspension, 3800 sc with intercooler, etc... The car probably tips the scales at 3400 to 3500 lbs without driver. I think your torque vs. acceleration was skewed by more than just the tallness of the tires.
My car tipped the scales at 2807 at the 30th and all my current round of upgrades there is a large focus on weight reduction to offset the weight of the turbo.
quote
Originally posted by Rickady88GT: Ok, now I am just benchtop racing, but just how loose are the tolerances on the shaft to make that much noise? Are the gear sets just floating on splines with crude snap rings holding them in a "general" location? If the same noise exists at operating temperature, then it goes without saying it isn't for expansion. Is there no fix? I assume that this noise will not decrease the life of the transmission? Will it get worse with time? And the question that everyone has asked, why would a manufacturer produce a product that sounds like it is already wore out?
The slop isn't between the gears and shafts, it is between the teeth of the meshed gears. I think the other factor is that the upper main shaft sits well above the oil level and none of the gears are submerged which would help reduce rattling. GM issues a TSB to reduce the oil level to that shown below (based on the discoloration of the case) they dropped it by about 1/3 in an effort to reduce the slight rattle (nothing like what my car has).
GM designed it to work with a super smooth idle and a 30+ lb dual mass flywheel. Even then it wasn't whisper quiet. But I wanted a choppy idle, light weight flywheels which causes significant oscillations in the crankshaft rotation at idle, which is why mine it probably one of the worst.
The fix is push the clutch pedal when stopped. That stops all movement inside the transmission and stops the rattle (as the video above shows).
The rattling to some degree is common with lots of manual transmission across several manufacturers, but it doesn't impact service life.
quote
Originally posted by Raydar: Just my $.02.
All true. Even with the rattle, I would do everything exactly the same way again. I am very satisfied with all the benefits of the F40, and just keep the clutch pedal pushed or slowly let out the clutch pedal when I am going to allow it to rattle.
quote
Originally posted by Rickady88GT: With a conventional clutch and flywheel, how much room is in the bell?
The F40 bellhousing is 1" deeper than the Fiero getrag, but the input shaft is about the same length. This means that w/o the dual mass setup, you still have to have a thick flywheel to put the clutch disk in the proper place to fully mesh with the input shaft. While my flywheel is only 12 lbs, it is 1 5/8" thick to take up the space of the dual mass flywheel.
quote
Originally posted by Larryinkc: I don't know if this would work in an F40 but it really helped with my gear rattle. I have a 3800 swap with a light flywheel in front of the Getrag 5 speed and it has the same annoying rattle at idle, kind of embarrassing sitting at stoplights in traffic. I worked my way through all the Red Line GL 4 gear oils, each one made a slight difference but even the with the 75W140 the rattle persisted. Against a Red Line tech's advice I put Heavy Shockproof in it and most of the rattle is gone and it actually shifts a bit better. I don't drive it in the winter but have driven it a couple of times with temps in the low 30s and it was a little bit stiffer, but not bad, until it warmed up. I only have about 1000 miles with the Shockproof and all is good so far, my research found that some Bimmer guys are running it for the same issue.
In the 6 years I have driven the F40, I have tried most of the various fluid recommendations from the Saab forums and other references to transmission rattling. I am using a 50/50 mix of redline MT-90 and one of their higher viscosity fluids. Didn't really see much benefit on my setup, but I don't want to go any thicker as it already made cold startup shifts noticeably harder.
In the 6 years I have driven the F40, I have tried most of the various fluid recommendations from the Saab forums and other references to transmission rattling. I am using a 50/50 mix of redline MT-90 and one of their higher viscosity fluids. Didn't really see much benefit on my setup, but I don't want to go any thicker as it already made cold startup shifts noticeably harder.
I probably should have tried the Lightweight Shockproof first, but I didn't want to toss any more expensive gear oil out. I may give the Lightweight a try, a seller on ebay has a gallon for $62.00.
Red Line info:
Lightweight Shockproof "Film thickness greater than an SAE 75W140, yet low fluid friction like 80W gear oil or 30W motor oil - Excellent low-temp flow, improved cold shifting"
Heavy Shockproof "Film thickness greater than an SAE 75W250, yet low fluid friction like 75W90"
So the noise is in neutral and the clutch out? No noise in gear with clutch in? Does it stop just by putting it in gear, or is it only clutch manipulation?
Originally posted by fieroguru: His car is great, but it has large heavy wheels front/rear, heavy brakes, heavier body kit, heavy stereo with amps, aftermarket dash and door panels, aftermarket suspension, 3800 sc with intercooler, etc... The car probably tips the scales at 3400 to 3500 lbs without driver. I think your torque vs. acceleration was skewed by more than just the tallness of the tires.
It makes me rethink ever wanting a wide body, when considering the additional weight it can add. Hadn't really thought about that.
It makes me rethink ever wanting a wide body, when considering the additional weight it can add. Hadn't really thought about that.
The shipping weight of the complete MadArch WideBody kit is 85 pounds that includes 24 pounds for the packing materials & cardboard boxes. The WideBody front fenders totally replace the original Fiero fenders & weigh just 2 pounds more than the original fiero fenders. So, that's not any more than 65 pounds. Period.
quote Originally posted by Rickady88GT: Ok, now I am just benchtop racing, but just how loose are the tolerances on the shaft to make that much noise? Are the gear sets just floating on splines with crude snap rings holding them in a "general" location? If the same noise exists at operating temperature, then it goes without saying it isn't for expansion. Is there no fix? I assume that this noise will not decrease the life of the transmission? Will it get worse with time? And the question that everyone has asked, why would a manufacturer produce a product that sounds like it is already wore out?
The slop isn't between the gears and shafts, it is between the teeth of the meshed gears. I think the other factor is that the upper main shaft sits well above the oil level and none of the gears are submerged which would help reduce rattling. GM issues a TSB to reduce the oil level to that shown below (based on the discoloration of the case) they dropped it by about 1/3 in an effort to reduce the slight rattle (nothing like what my car has).
GM designed it to work with a super smooth idle and a 30+ lb dual mass flywheel. Even then it wasn't whisper quiet. But I wanted a choppy idle, light weight flywheels which causes significant oscillations in the crankshaft rotation at idle, which is why mine it probably one of the worst.
The fix is push the clutch pedal when stopped. That stops all movement inside the transmission and stops the rattle (as the video above shows).
The rattling to some degree is common with lots of manual transmission across several manufacturers, but it doesn't impact service life.
quote Originally posted by Raydar: Just my $.02.
All true. Even with the rattle, I would do everything exactly the same way again. I am very satisfied with all the benefits of the F40, and just keep the clutch pedal pushed or slowly let out the clutch pedal when I am going to allow it to rattle.
In the 6 years I have driven the F40, I have tried most of the various fluid recommendations from the Saab forums and other references to transmission rattling. I am using a 50/50 mix of redline MT-90 and one of their higher viscosity fluids. Didn't really see much benefit on my setup, but I don't want to go any thicker as it already made cold startup shifts noticeably harder.
This is very interesting. Back in 2006 after the G6 was introduced, the first 6 6 speed swaps I did for customers. I bought all the transmissions over-the-counter from GM. In total I've had the rattling on 2 cars. One was on one of the over-the-counter transmissions & the 2nd one was several years later on one of the Ebay transmissions. I've done more than 80 6 speed swaps & only had this "rattle" on 2 of them.
I had the same rattle in neutral with pedal out & the other things you've described & I would have described them exactly in the words you've used.
However, I put the cause on the 3rd to 4th Synchronizer fork rattling. I did this by with the engine running & the lever in neutral, I I move the lever to 1st & 2nd select position. Then I just moved the lever forward & backward just a little with no change in the rattle. However when I did the same thing in 3rd & 4th the rattle went away. Then 5th & 6th the rattle continued. I then (under the shift plate cover) I put a rubber band on the shifter to move it just a little back towards 4th gear.
The permanent cure for that car & the other one I did later that rattled, was to put a real light weight throttle return spring on instead of the rubber band.
Originally posted by Archie: The shipping weight of the complete MadArch WideBody kit is 85 pounds that includes 24 pounds for the packing materials & cardboard boxes. The WideBody front fenders totally replace the original Fiero fenders & weigh just 2 pounds more than the original fiero fenders. So, that's not any more than 65 pounds. Period. Archie
Yeah, that's not a lot of weight, but it adds up. Of course there's some glass work which might not add a bunch but is relevant to the weight added. Then the rear wheels have to be exchanged for larger ones to fill the added width. I don't know the stock wheel weight to compare. The fronts probably don't have much weight gain. 65 lbs isn't a lot but there's a little more weight additions needed with the wide body.
The shipping weight of the complete MadArch WideBody kit is 85 pounds that includes 24 pounds for the packing materials & cardboard boxes. The WideBody front fenders totally replace the original Fiero fenders & weigh just 2 pounds more than the original fiero fenders. So, that's not any more than 65 pounds. Period.
Originally posted by Archie: This is very interesting. Back in 2006 after the G6 was introduced, the first 6 6 speed swaps I did for customers. I bought all the transmissions over-the-counter from GM. In total I've had the rattling on 2 cars. One was on one of the over-the-counter transmissions & the 2nd one was several years later on one of the Ebay transmissions. I've done more than 80 6 speed swaps & only had this "rattle" on 2 of them.
The use of a 14" diameter flywheel and GM crate engines is probably a significant contributor to your results. Both of these items keep the crankshaft oscillation damping closer to stock.
There are no manuals for the F40 transmission, so needed to figure out what the factory preload was for the differential and both main shafts...
...Once I had the differential preload, I took it apart, added the upper main shaft, reinstalled the gear side case, torqued and measured preload drag again. Then did it again with just the lower main shaft... That gave me 3 preload values that I would try to replicate.
Did you record the preloads for those main shafts?
We just rebuilt an F40 for an awd Saab 9-3 pushing over 700 to the wheels, we were unable to find any info on bearing preload as there are no manuals like you mentioned.
Originally posted by Aero_GTX: Did you record the preloads for those main shafts?
We just rebuilt an F40 for an awd Saab 9-3 pushing over 700 to the wheels, we were unable to find any info on bearing preload as there are no manuals like you mentioned.
The differential preload was 15-20 in-lbs. Adding one of the main shafts raised it to about 30 ln-lbs.
I already have a spare new F40.
