Tranny and around

I gonna talk here about the torque converter, transmission and everything which behind it in the driveline. Transfer case, propshafts, diffs, driveshafts. The Syclone has an All Wheel Drive system, with automatic transmission with no external control.

Torque Converter

If you plan to change to a larger turbo you will need a different TC. Our stock torque converter has a 2200 stall speed with automatic lockup in third gear around 65MPH. The most popular stuff here is the 9/11" converter designed by Brian Hartman. It's a hybrid unit where you have a 9" converter with less mass to rotate and a 11" lock up clutch with enough strength to really lock it up. You can talk to Brian and choose a stall speed for your combination so you can customize your stuff as you want. I wouldn't recommend any other converter, but this. You must choose your stall speed wisely because with a lower one you will bog of the line, but a higher than required will generate more heat and speed up the wear on your tranny and TC. * One thing you can do with your stock and with the 9/11" converter too is to alter the lock up point. Most popular way to do this is to make a shortcut between the A and F ports of the ALDL terminal. You can do it with a paper clip, but a more convenient way is to 'T' the two terminals at the back of the ALDL conector and take the two wires to a switch mounted somewhere on the instrument panel. If you make a shortcut it will lock up right after the 1-2 shift. If you have a switch you can lock it anytime but in 1st. This can make you 0.1-0.3 second quicker on the quoter. You must note that the lockup at WOT won't make any good TC's lifetime wise.

Transmission

It's a GM 700-r4 aka. 4L60. It's a four speed automatic, with overdrive used in a lot of other vehicles of that era. It was used till 93' and was replaced by 4L60E in 94'. The gear ratios are the 3.06, 1.62, 1.00 and 0.70 across the four gears. The reverse ratio is 2.29. * The 4L60 used in SyTy's is not the same as a regular 4L60. The differences which I know of are the following.

• different separator valve
• different valves body
• different 2nd gear servo
• different PR valve spring
• different boost valve
• different vacum springs
• different governor
• different output shaft

It's said to be Vette transmission internals swapped into a 4x4 configuration. The VB and the separator plate are completely uniqe. * As far as replacement there are a lot of to do. This depends on the truck and on its owner but there are a bunch of stock trucks eating trannys as pancakes and there are several one which could more 100k miles with the original tranny. Anyway if you wanna modify your truck even mildly you should count on a tranny rebuild sooner or later. And this where the real though stuff is starting. The tranny is the most advanced part of these truck so it requires a huge amount of knowledge and experience to know what you are doing. Of course you can take your truck to a tranny shop and make them rebuilt it, but in most cases a average shop won't use the best parts, won't realize the differences to a regular 4L60 and so on. You will end to an other shop soon enough. This is especially true in a country like Hungary. * So. My suggestion would be to do it yourself. It requires some special tools, but first of all it requires to choose the right parts and methods. There are two ways which could take you to the desired result. One, you can buy s SyTy specific rebuild kit. Brian Hartman is the man if you want to do this. He is a nice guy with tons of experience and will help you through your rebuild saga. Two you do you home work, talk to a lot of people, gather a bunch of info and collect the parts yourself. Well this second one is cheaper, but more risky and lengthy too. But it can be done. I will try to educate myself continuously and will choose one of the above two routes when the time comes. Hopefully I still have some time to widen my knowledge in the area.

Cooling

This is the thing which everyone should do. There are quite a few not too expensive things which can dramatically lengthen your transmission's life. The main goal is to keep its operating temperature in the desired range. Desired range? Well everything above 200F is bad. I'd say something around 140F is good. I can easily keep this temp with the below setup.


* You can serialize an additional tranny cooler with your existing one on the passenger side of your engine cooler. First I choosed the smallest B&M 16000 GVW (#70255) unit mounted before my air condition cooler on the passenger side. I found that with this unit my tranny temps still could reach 180F's during the summer so I upgraded to a Hayden 1404 unit. Now I can't take my temps above 150-155 F's whatever I do. I also got made a 'T' piece put into the tranny return line where I could mount the sender of my Autometer tranny temp gauge in(#2640).


* I changed my stock tranny oil pan with a deeper Derale unit (#14104) which has some inner cooling tubes. These tubes can help to lower the temperature, other hand you don't have to use a longer neck filter, because the stock filter lays on these tubes. This pan is a direct bolt on and also has a drain plug. There are other deep pans, TCI, B&M and even from GM, but this seems to be the best bang for the money. Some guys are complaining that it's leaking at the welding, but I'm completely happy with mine.

Transfer Case

The brain of our AWD system. It's a Borg-Warner 4472 unit, in aluminium case, chain driven, viscous clutch. The torque is divided into 65% to rear, 35% to front by a planetary gear set. The transfer case is a not reparable unit, so you have to replace the whole case if you have broken it. The SyTy's were not the only vehicles which used this case. You can find the exact same part on AWD Astros for example. * There are not too much which you could do to strengthen your transfer case. The only thing is to change the fluid regularly as I described it in the Maintenance section. An other thing could be to threw it away and convert your SyTy into RWD. Well... IMHO the SyTy's are 4.3 turbo, AWD trucks even if AWD became a draw back above a performance level. You might be able to make faster your 'all out effort Sy with an RWD conversion and slicks, but whit this move you would lose one of the best feature of these trucks. There are currently a few RWD trucks running high 9's and a few AWD running high 10's. However the gap is more narrow than ever. Some time we might see an AWD Sy in the 9's.

Front propshaft

Well. I've a bad experience here. The stock unit was made by Dynotech and has an expensive double cardan joint with a boot on it. This boot is tend to break and lose all the grease inside, collect dust and finally the shaft will break. So replacement of the front propshaft is on everyone's list sooner and later. I got my truck with a damaged boot so I had to replace mine too. * There are several way to choose from.

• If you can find a good shop you can make rebuilt your stock one. I've not choose this way, because I don't know how long it was opened and how much damage was made to the joint itself. Anyway, maybe this is the cheapest way
• NAPA (#12-352) make a replacement shaft. It's quite cheap (around $300), but quite a few owners had vibration problems at higher speeds. I guess it's not perfectly balanced
• The next way to go could be Brandon's propshaft. The cardan joint has been eliminated and the whole stuff should be more durable than the stock one or the NAPA one. Well, it should be...
• ATR make a replacement one which you can buy from Rick atRK Kustom. It a bit more beefy, and a bit more pricy too.
• Al Dustan is making an aluminium propshaft. It's quite new and a bit more expensive than the previous three and at this time nobody has experience with it.
• I've just heard that Brian Hartman gonna release a propshaft but I don't have any more info on this so far.
• Finally you can get a new one from GM, but it will cost you mega bucks.

Well. I decided to buy a propshaft from Brandon. It looked good and was direct replacement but that where the fun ends. I managed to break the shaft on the first 20 miles or so. I made nothing special, just started from idle and heard the bang. I was lucky, could stop immediately, so it has not cracked the tranny, the floor or the fuel tank. If this happens, let's say at down shift at 40MPH, it could destroy my tranny. It had happened in the past. Anyway I had to send my wife for tools and removed the propshaft at the side of the road in the dark and rain. I could get it off in half an hour but it was not funny. Anyway after closer inspection you can see that it cracked at an obviously inappropriate welding.


Finaly I could make the broken PS welded and balanced again. Brandon was nice and coverd my expenses. It has alredy lived through a few hard launches. I can feel some vibratinon now which starting ~85MPH. Will try to reclock the PS, it might help. Hopefuly the other two welding on the PS will do better than this one.


* One other thing you can do if you replace the stock shaft is to get rid off the stock bolts too. It has an outside torqs heads so you will need an E10 wrench in the front and E12 in the back. Yes it's metric, M10-1.50x25 in the front and M12-1.75x 25 in the rear. I removed these because they are too bulky so you don't have enough clearance around them. They are easy to strip off too. I used inner hex heads bolts and they were much more easy to handle. Anyway, be aware that you should use grade 10.9 bolts if you don't want to break them.

Front differential

It's a 7.2" house but not too much more info here. There are a few people talking about replace it with a locking differential, but it doesn't seems to be a good idea and very few people actually made this swap out there.

Rear shaft

Again not too much info here. The stock shaft seems to be fine, however there are a few experimental tries to replace it with a lighter one. Al Dustan and Brian Hartman the names here too.

Rear differential

Our rear differential is limited slip with 3.42 gear in a 10 bolt 7.5" house.


It's not a usual thing to change this gear ratios, but on the other hand it's quite popular to change the diff cover to shinny want with a magnetic drain plug. You can get a chrome plated cover from Summit or from ATR too.




Drive shafts

Still looking for info here. Al Dustan is making some good replacement driveshafts, so you can check with him if you have replace them. *