3.73 confussion ?'s

[imported_germ]

ok, so i have the 3.33 W body tranny now....

all i need to get is the DSCR and then follow these directions...

"2.8W-3.1T/3100M,J CWM Code- This procedure is reserved for the experienced Mechanic that understands the automatic transmission. This procedure can be adapted to scavenging a DSCR from a CWW trans as well. DCSR from a CWW 3.4 TDC transmission will need to be obtained. Also you will need a Side cover gasket set (depending on year), and a valve body/channel plate gasket service kit. At this time you may also want to replace solenoids and DCSR thrust washers and replaced the drive chain as well. Drop the trans pan, drain fluid, replace the filter, and reinstall the pan. As per GM service manual, obtain access to the side cover and remove it. As per GM service manual remove everything needed to remove the channel plate. The DCSR and chain should now be completely visible. Now to be quite frank... you can actually start to pull the innards out and overhaul the transaxle thoroughly. But to focus back on the DCSR, remove the 4th clutch plates and the 4th clutch hub (just pull repeatedly on it if it does not want to pull out all the way). Remove the plastic DCSR thrust washers. Being careful not to remove the Driven Sprocket support, start pulling both chain sprockets and chain, making sure the driven sprocket is biased towards being removed first. Make sure you pull the drive Sprocket only as far as it’s willing to go possibly about a ½ an inch. The DCSR will come off the driven side 1st. Replace parts as necessary; replacement is reverse as per Technical Manual. Makes sure that if the chain has a blue link, keep it faced the same said it was installed, either facing the pump or facing the Torque converter. Note if the Drive Chain is replaced with either a new chain or a chain that wasn’t in service with the sprockets then you may hear a slight whine under power in lower speeds. This whine is actually very appealing, very classic sounding. DON’T FORGET TO FILL YOUR TRANSMISSION UP TO THE CORRECT FLUID LEVEL!!! USE DEXRON3/MERCON FLUID ONLY.
The 3.73 FDR is one of the many ways to refit the 440-T4/ 4T60-E. This ratio will help your application step off the line a lot better and make cruising a snap. Proper understanding of the transmissions is mandated before making any attempt on refit."



it says that i need to get a DSCR from a CWW tranny. WTF is a CWW tranny? that ANY 3.43 91-97 60e right? and that basically means the chain and sun gear right?

is this something that can be bought from the dealer? or should i just get a donor tranny and pull it all out.


if anyone has an "extra" set of this stuff laying around i would be willing to trade a 3.33 diff to a DOHC owner so you can get the 3.73 and i can get the 3.73's as well. im willing to buy the stuff to if you dont want to trade.

[dbtk2]

RE: 3.73 confussion ?

I am interested in doing the same thing, so if anyone knows exactly what needs to be done, I would appreciate it. Have to get the tranny rebuilt anyways.

Shawn

[sharkey]

RE: 3.73 confussion ?

well, re-reading that artical, a cww tranny comes behind the 3.4l tdc (or dohc if you prefer) motor. cww is the transmission code.

[gpse3400]

With a 3.1 equipped car CMW Trans you'll need the sprockets from a 3.4TDC equipped car CWW trans. That will give you 3.73

[j.r.]

So is 3.73s the best or can we get like 4.56s? I got my car just to take to the track and put down Imports.

[dbtk2]

Since there aren't any aftermarket parts available for them (that I know of), then we can only use stock parts to change the gearing. So due to that, we can only get 3.73s. But if someone would produce an aftermarket kit for them, obviously shorter than 3.73s would be possible.

Shawn

[grandprixgtp_91]

ok ive got 2 4t60-e's from a 3.4Ldohc in my garage, i dont know what the FDR is but i would like to make it a 3.73 , if you are saying all we have to do is switch some parts so we both have a 3.73 set up then ill do it, just give me a list of parts i need and you need and we can go from there.

Jake

[pontiacjeff]

O.k, o.k, here's the deal.

There are three differential ratios and four chain drive ratios available for the 4T60E. This gives a total of twelve possible FINAL DRIVE ratios (FDR).

See, the input shaft drives the chain, which drives the mainshaft. The chain uses two gears to do this, the "drive" gear (input shaft) and the "driven gear" (mainshaft). If these two chain gears have the same number of teeth, we call that a 1:1 chain drive ratio. However, if the tooth count from the two chain gears is different, the chain drive ratio changes. As mentioned, there are four possible chain drive ratios, achieved by changing tooth count on the drive and driven gears (BTW, the chain is the same for all ratios). The tooth count and ratio is given as follows: drive gear:driven gear/ratio...

1. 33:37/1.12:1 (underdriven)
2. 35:35/1:1 (direct drive)
3. 37:33/.89:1 (overdriven)
4. 38:32/.84:1 (overdriven)

The effect each of these ratios has on the FDR is stated in parenthesis.

Now, the differential ratios are as follows, reflected in the number of teeth on the differential sun gear:

1. 2.84 (38 teeth)
2. 3.06 (34 teeth)
3. 3.33 (30 teeth)

The most common 6/60 FDR is 3.33. Most W-bodied 3.1's and 3100's have it. The 3800 cars and the 6/60 N-bodies use a 3.06 or 2.73. The 3.4TDC/DOHC cars use 3.43. There are other exceptions and optional ratios, etc.

Now, if you have a 3.33 ratio, you have the 35:35 chain set and a 3.33 diff. If you have a 3.06, you have the 35:35 chain and 3.06 diff. Easy to see, right?

Now the other combos... a 3.43 is a 3.06 diff with the 33:37 chain, so 3.06 x 1.12 ratio = 3.4276 or 3.43. Another common ratio is the 3.18, which is a 2.84 diff with the 33:37 chain, 2.84 x 1.12 = 3.1808 or 3.18. The 2.73 is a 3.06 diff and 37:33 chain: 3.06 x .89 = @2.73.

So now that you see how it's done, let's build the 3.73!

If you have a 3.33, you already have the highest ratio diff. You need the 33:37 chain drive set. This gives 3.33 x 1.12 = 3.7296 or 3.73. If you have a 3.06, the underdrive chain set will give you a 3.43 best. You will need to change the diff to a 3.33 to get the 3.73.

NOW, the 33:37 chain gears are about 125.00/ea from GM. Lucky for you all I have been squirreling them away over the years. They can be replaced in the car, but I would highly recommend it NOT be done that way. The diff can be changed easily and one could go from a 3.06 to a 3.33 rather easily.

REMEMBER!!!! ANY change in ratio of any kind on any "-E" transmission will require custom chip reprogramming as all shift points are dependant on road speed and rpms. These two factors change any time the FDR changes.

I hope this clears up the issue of FDR in the 4T60E. Thank you and have a nice day.

[bszopi]

Thanks for that Jeff! Might have to steal that and put it on the main 4T60E area of the site...

[pontiacjeff]

That was my intention! As long as due credit is given

[bszopi]

Of course! I always try to make sure that anyone who contributes to the site is mentioned. I'm sure I can ever link to EP if you want me to...

[bszopi]

Here you go...

http://60degreev6.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=60&page=1

[95naSTA]

so, just to double check,
If i have a 3.06 now and i install a 3.33 differential/cover, i'll have a 3.33?
And i'm assuming the axles are interchangable?

-Edited for being confused.

[pontiacjeff]

so, just to double check,
If i have a 3.06 now and i install a 3.33 differential/cover, i'll have a 3.33?
And i'm assuming the axles are interchangable?

-Edited for being confused.

Yes, your 3.06 uses the 35:35 chain gears, so you can go to a 3.33 without pulling the transmission.

[95naSTA]

Awesome, thanks.