I am told the gearing in the 4t60e can be easily changed by swapping sprocket and chain under the side cover....does anyone have more detailed info on this?

Also, does anyone have info on how to determine the gearing that is in the trans in my car?

quote Originally posted by Cplensdorf: I am told the gearing in the 4t60e can be easily changed by swapping sprocket and chain under the side cover....does anyone have more detailed info on this? Also, does anyone have info on how to determine the gearing that is in the trans in my car?

To determine what "gearing" your 4T60-E has, get the numbers/letters off the ID tag attached to your trans and compare them with the info found here:

http://dtcc.cz28.com/transmission/index.htm

On 4T60-E's there are typically 3 different ratio differentials and 3 different ratio configureations for the drive chain sprockets. Changing out a differential is a lot easier than changing chain sprockets. To change the chain sprockets, you MUST pull the side cover, valve body, and channel plate. If you haven't ever rebuilt a automatic trans, I strongly suggest you have someone else attempt this.

Concerning final drive differentials, there are 3 different types:

-Units with "regular pitch gears" that were 2.84, 3.06, and 3.33 ratio; these were used in 1991-1997 transmissions.
-Units with "fine pitch, reverse cut gears" that were 2.86, 3.05, and 3.29 ratio; these were only used in SOME 1995 transmissions.
-Units with "fine pitch gears" that were 2.86, 3.05, and 3.29 ratio; these were used in some 1996-up 4T60-E transmissions.

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The available combinations for the 3T40 and 4T60 are in my cave. I'm not quite sure if they are exactly the same on the 60E but would guess they are. The main dif between the E and Non E is the valve body.

You have to pull the trans apart quite a bit to get at the chain set. If you botch it, you'll kill the trans. (I think there are expanded views at the trans parts site listed in the same article. Haven't looked recently.)

The only way to tell what you have after the unit is separated from the donor vehicle is the code on the trans. I don't have any of that info.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
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I this any more difficult or must I go any deeper than installing a "shift kit"? I have done several of these on th350/400's in my day.....

quote Originally posted by Cplensdorf: I this any more difficult or must I go any deeper than installing a "shift kit"? I have done several of these on th350/400's in my day.....

Changing the drive chain sprockets is a little more involved that just doing a shift kit, but if you have pulled valve bodies before it shouldn't be that big of deal to you. However, I wouldn't attempt to do this with the trans still in the car.

Changing out differentials is MUCH easier and can be easily done in the car. (on 4T60-E's only....440T4's, 4T60's and 125-C's require the trans to be completely disassembled to access the differential).

Whatever you decide to do, I strongly suggest you get an ATSG Techtran manual for the trans you are working on. They cost less than $20 and most transmission supply companies sell them. If you can't find a vendor in your area, let me know.

-ryan

[This message has been edited by Darth Fiero (edited 02-25-2006).]

When you change something like the gears ratios, do you need to reprogram the pcm ?

Depending how far you change them, yes or no. Also depends how tolerant the PCM is...

The PCM on the E units uses the VSS signal, Engine RPM, and a few other things to control shifting. If the gearing change is large enough, it will screw up your shift points. It can also trip DTC as the PCM may think the trans is slipping when the TC should be locked. IE the PCM may think you've got a bad TC clutch and besides the code may refuse to lock it at all, which cuts MPG and heats up the trans.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurasic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

So, where can I obtain the differentials? What do they cost?

quote Originally posted by Cplensdorf: So, where can I obtain the differentials? What do they cost?

Your local transmission service shops would be your best bet. They usually have a ton of cores on hand and will be able to determine what ratio and type they are. Junkyards sometimes will have good units, but more than likely they won't let you take a differential out of a good transmission.

I changed to 3.29 gears in my 65E-HD when I built my motor up. Let me say first off, take it to the trans shop and let them do it. I tried it myself, layed everything out perfect, thought I had it down, it turned into a mess. I ended up pulling out some clutched from the first pack and from there is was down hill. So after many hours of work, gettin very mad, going to the trans shop and a 100 bucks, I had gears in m y trans. I can say the gears are well worth it.