4T45 Tanny mods (help)

[john_V63400]

I am going to need some tranny mods, I have a 4T45E in my 01 GA GT.
Yes it is supercharged, I know the tranny is not going to hold forever, So what after market parts can I buy to install in my tranny to make it stronger. Im trying to avoid buying a new one. Ive already upped the preasure, and I have a tranny cooler as well, seems to being doing ok for know, but Im replacing a silinoid so I want to add something as well to make it hold up better, any sugestions.

[geoffinbc]

Well you did one good thing by increasing pressure, That will give you more holding power. But going further into the tranny and increasing the number of clutches or getting clutches with more holding power will prevent slipage. The 4T40 is a great tranny to begin with. Its design is strong and simple. It is also a progressive shift tranny. Also buy yourself some type of programmer or software and change the shift points and firmness.

[torq455]

ummmm, thought the 40 and the 45 are the same. just the 45 has more clutches--according to a tranny shop.

[tejohnson]

The following gallery, and it's subs, may be of interest:

http://groomlakelabs.com/?q=gallery&g2_view=core.ShowItem&g2_itemId=824

[geoffinbc]

ummmm, thought the 40 and the 45 are the same. just the 45 has more clutches--according to a tranny shop.

Most likely they are. Im sure there are a few other components that seperate them

[geoffinbc]

Ha ha I just took a look at that link about the 4T40 thing. I laughed when I read "it seems as though im the first person to break an EP diff" Well shit does he think it is something special? And EP diff is just a stock one machined to accept a limited spli clutch pack and springs. Nothing about it is stronger. I bet the guys at EP said that to him LOL

[tejohnson]

lol... Um, that is my site And the reason I mentioned that I must have been the first one is "since I have never heard of one braking before...." Technically is is not stock, but more of a swap for the 45e. It is just a 65e carrier housing, with a few thrust plates and springs, which makes it a bit of a tight squeeze. Hence the damage to the case by the reluctor ring... And it is a 45e

[Azrael]

From what I understand, the only difference between the 40E and the 45E is the final drive ratio. 3.05 and 3.29 respectively.

[tejohnson]

Actually, the 45e has a final drive ratio of 3.05 (in the GA SE) & 3.29 (in the GA GT).

Between the 40 & 45, there are differences in the drive chain and driven sprockets though. There are other subtle differences as well like the input speed sensor. To get a better understanding, it is easier to look over parts explosions or differences in part numbers. Unfortunately, I don't believe there is any definitive description of the major differences between the two.

[AaronGTR]

From what I understand, the only difference between the 40E and the 45E is the final drive ratio. 3.05 and 3.29 respectively.

Nope, like tejohnson already said, there are some other differences. Basically the 45e is the newer and beefier version and is the best starting point. They also have made some improvements to some of the stock parts over the years (some stronger thrust bearings, pump shaft and bearing, revised seperator plate, things like that) and any comprehensive rebuild should include those parts.

It's also usually a good idea to get new shift solenoids and/or a new torque converter in case they are contaminated (probably with burnt clutch material) or just worn out. You can also get a custom torque converter in the $400-$450 range. For after market parts, you can get the EP LSD, raybestos blue clutches, and superior aluminum accumulator pistons. Anything beyond that has to be custom right now, like cryo treating gears or nitride coated steel plates (for between the clutches). Hope that helps. I've done some of these myself, but I've only rebuilt it once so I'm pretty much following Todd's build now. He's on the for-front of 4T45 modification.

[prophiseer]

Hey all, new here; not to knowledgeable on the tranny internals, but was wondering if y'all knew how much of the internals are compatible between a T45-E and a T60-E. I figure not much, right?

[tejohnson]

Unfortunately... Not much.

[prophiseer]

thought so

Prob be easier to just swap trannies, then