Thread: Looking for Trans Rebuild Info

Since your question and post title was specifically about the trans, I'll move this over to the tranny section.

Welcome to the community.

Hi Rem, is your car stock or will it remain near stock? There are a lot of upgrades for these transmissions and a lot of different ways to build them. There are also quite a few common problems with them and parts that should be looked at during a rebuild whether you had issues or not. The link below is one to my website that has a lot of usefull info on this trans.

4T65E Transmission Info

You will need to get a trans tech manual to walk you through the process but it isnt going to tell you the common stuff to look for. As a minimum you should replace all the solenoids, get a hardned 4th clutch hub as the stock ones strip out over time which makes you lose 4th, replace the clutches and steel plates, gaskets, seals, molded pistons, inspect and replace if needed input clutch piston, inspect bands for wear and burning, Transgo shift kit which includes an upgraded boost valve and new accumulator springs, and also you should replace the torque converter with a reman one. This is a basic list and the rest depends on the condition of your transmission after you tear it apart. If you have any questions along the way ask away

That kit will give you the "soft" parts so to say for a rebuild and is a good quality kit at a reasonable price. That kit does not include ANY hardparts such as gear train, drums, sprockets, chains, shafts, bushings, bearings and those are things that will need inspected once it is apart to determine the need for replacement. You also need to replace the 4th clutch shaft with a hardened one. There are a lot of great converter companies out there, and there are also bad ones. I have used a number of different ones and here are a few to help your search.... Precision-I currently use these, CVC, Dacco, ATC, ACT and there are a few others I have used over the years but any of those are good quality converters. Again there are many more out there but I cant speak for them, well I know a few bad companies but I will leave that out. I would stay away from a Napa or Autozone converter if they would even sell one and go straight to a trans shop or I could sell you one if that helps out.

Not sure which companies you are referring to but the ones I have mentioned use the colors you say to beware of, most companies use silver or blue paint on reman converters. I have also never seen a pump shaft break on these transmissions. I have seen incorrect installation ruin the splines and also splines wearing on the converter side after very high miles on some cars. In the 10 years I have been building I am yet to see a reman converter from the companies that I have used fail on GM fwd transmissions. Aftermarket performance converters.... That is a different story and you get what you pay for.

Yeah unfortunately that is all a lot of converter builders do, cut it open, clean it, weld it back together and paint it. They have $5-$20 in rebuilding a converter and sell it for $100, its a goldmine company but once you make a bad reputation it is hard to change that. I havent used Dacco converters in a long time and mainly used them for performance upgrades as they offered a great line of inexpensive quality converters but they had a lot of limits as to what they would do and it just wasnt in my interest to continue using them anymore.

Trannyman, if I may hijack this thread for a moment, is the heat treatment sufficient to overcome the stripped spline condition or is there more that could be done?

Also, according to GM, ~03-04 newer hardened 4th clutch shafts were introduced from the factory. This true?

Originally Posted by Sabrewings

Also, according to GM, ~03-04 newer hardened 4th clutch shafts were introduced from the factory. This true?

Thats a good question since Dave recently saw the inside of my transmission.

The 03/04+ 4T65E transmissions did come factory with the hardened 4th clutch hub. Lee, yes yours does have one in it so you dont need to worry about it. Scotty I have never seen a heat treated one fail, even with well over 100K miles on them. I use aftermarket shafts and have also seen used ones from one of my suppliers as they will sell the used hardened shafts and I a didnt even see any of those that looked worn.

Yeah the older 440T4s and 4T60Es didnt see this near as often and was the clutch end that would get chewed up more. One thing I have noticed on the 65s if that the minivans and 60deg V6 cars go through these shafts more often. Its one of those gray areas but I always felt that those cars cyclined in and out of 4th under load a lot more frequently which is going to hammer on the splines more and cause them to fail sooner. Regardless the newer shafts seem to address the problem and I havent seen one come back nor have I had anyone tell me about one failing.

Okay, Trannyman, if I may. Let me ask this then. Lets say I have a new 4th clutch hub that has not been treated. Can I get it treated or how would one go about doing so.

The reason I ask, is that the middle of last year when my tranny problem first showed its head, I bought what I was told was a hardened shaft in preparation for rebuilding. However the splines were not discolored or anything like it had been heat treated. So either I have a hub from a newer tranny or it isnt hardened and I want to be sure it is before it even catches the vapors of tranny fluid of my transmission.

I thought it was mid 01 and up that had the hardened shaft stock

This is DAVE lol this two people thing gets cOnfuZInG!!!

I have rebuilt numorous 02 trans's and none of them had the hardened shafts. I even had an 04 Comp G trans that I believe may have been a GM test trans and all of the parts were cast in 02 and it even had the old non hardened shaft. Most of of the 03 and all 04+ that I have seen have the hardened shaft. Scotty the new ones from GM through the parts counter or out of a late trans have the discolored/ heat treated splines so if yours are shiny fresh machined looking then they are not heat treated. There was a lot of that stuff floating around a while back as it was old stock. One of my suppliers buys a lot of stuff in bulk that is OE trans company old stock and overflow and they were selling the old shafts brand new for around $20 but whats the point unless you plan to treat it on your own, its gonna fail too down the road. As far as heat treating I dont know where to point you. We have places in town that specialize in heat treating metals but I have never used them so dont know what the cost would be, but you should justify that before spending the money on it and maybe just go the route of a new treated one.