- Dec 8, 2011
- 501
I finally was able to install my Transgo shift kit, separator plate, and replacement accumulator pistons. Wow, what a difference. Its almost like driving a different truck. Nice smooth, fast shifts. No more “hanging” between shifts! The short story to this is that a couple of months ago I noticed that it was hunting between 3 & 4 much more than it normally should, especially when the trans was cold. One of the suggestions was that it might be a worn separator plate. Turned out it was low fluid. However, being that I have 150k on it and tow a travel trailer, I decided to do the upgrades anyway because I want to get as much out of this truck as I can. All in all, it was well worth the effort! I highly recommend doing this if you are mechanically inclined and hate the sloppy performance of the 4L60E. This was fun to do and a great learning experience. Read on for more detail of my experience...
This is not a how to post, see the links below for excellent detail on how to do this. This is just to share how my upgrades went and some lessons learned. The threads below were a big help, as are the BoxWrench videos on YouTube. This was not a physically hard job, just tedious and time consuming. Now many people swear by the notion of having an axillary transmission cooler. I did put one on a few months ago because I'm now towing a larger, heavier trailer than I used to. However, based on the condition of my valve body and separator plate, I'm not convinced that we need them. With all the miles on mine, I was expecting clear evidence of wear and tear. Not only were the plastic accumulator pistons in perfect condition, the separator plate looked great also with no signs of check ball damage. I think the secret is preventing gear hunting on hills and in the wind. Adjust your driving to accommodate the conditions. And use Dexron VI on the older transmissions that came with Dexron III.
I don't need to repeat everything in the posts below, but here's a couple of notes.
1) If you do this, put everything back exactly the way you found it unless the instruction sheet tells you otherwise. In dfc739's accumulator post (linked) there is a shot of the first accumulator piston and spring. Mine was not like that at all, the crown of the piston on mine was facing the separator plate, not the spring. After the fact, the only info I can find on the correct position is that it was changed by GM at some point in the 4L60E's history. There seems to be differences of opinion as to the effect of having either the spring or the piston head face the separator plate. Hard shifts vs soft ones. Supposedly the change was made to soften the shift between 1st and 2nd.
2) The TransGo instructions show 3 possible piston types for the 1-2 piston. The one I ordered was not the one in the transmission. Since it said to reuse the same spring anyway for my type of piston and I didn't have the right piston, I put the plastic one back in. I didn't want to, but its an easy piston to get at and doesn't require removal of the valve body so I may replace it later. I was however able to replace the other accumulator piston on the valve body.
3) I did not enlarge any oil holes on the separator plate. Aside from one item that I didn't install anyway, instructions say that “you will be pretty happy” with the plate as is and enlarging some of the holes is optional. I can say that I fully agree. It shifts beautifully.
4) Trust the instructions, in that several of the spring replacements may be a bit shorter than the factory ones. This is to change the shift firmness and speed. It made me a bit nervous until I drove it.
5) The basic shift kit that dfc739 links to also includes some springs that are used for a valve replacements that don't come with the kit, and there are springs for parts in the pump which I understand requires removal of the trans to install. There are also springs for the 2-4 servo that I didn't replace (see #7).
6) In hind sight, I wish I had bought just the shift kit first to understand what other things I could have ordered to make it more complete. Then again, I'm not sure I would have fully understood until I had the valve body out.
7) I did buy, but did not install the Corvette servo. Time was getting away from us (5 hours to do this!) and since we didn't need to remove the cross member anyway to get at the pan, I decided not to bother with the servo. So there was a bunch of extra stuff in the kit for the 2-4 servo as well that didn't get used.
http://gmtnation.com/f93/how-remove-4l60e-valve-body-replace-plastic-accumulator-pistons-4972/
http://gmtnation.com/f24/built-4l60e-replacement-4894/
This is not a how to post, see the links below for excellent detail on how to do this. This is just to share how my upgrades went and some lessons learned. The threads below were a big help, as are the BoxWrench videos on YouTube. This was not a physically hard job, just tedious and time consuming. Now many people swear by the notion of having an axillary transmission cooler. I did put one on a few months ago because I'm now towing a larger, heavier trailer than I used to. However, based on the condition of my valve body and separator plate, I'm not convinced that we need them. With all the miles on mine, I was expecting clear evidence of wear and tear. Not only were the plastic accumulator pistons in perfect condition, the separator plate looked great also with no signs of check ball damage. I think the secret is preventing gear hunting on hills and in the wind. Adjust your driving to accommodate the conditions. And use Dexron VI on the older transmissions that came with Dexron III.
I don't need to repeat everything in the posts below, but here's a couple of notes.
1) If you do this, put everything back exactly the way you found it unless the instruction sheet tells you otherwise. In dfc739's accumulator post (linked) there is a shot of the first accumulator piston and spring. Mine was not like that at all, the crown of the piston on mine was facing the separator plate, not the spring. After the fact, the only info I can find on the correct position is that it was changed by GM at some point in the 4L60E's history. There seems to be differences of opinion as to the effect of having either the spring or the piston head face the separator plate. Hard shifts vs soft ones. Supposedly the change was made to soften the shift between 1st and 2nd.
2) The TransGo instructions show 3 possible piston types for the 1-2 piston. The one I ordered was not the one in the transmission. Since it said to reuse the same spring anyway for my type of piston and I didn't have the right piston, I put the plastic one back in. I didn't want to, but its an easy piston to get at and doesn't require removal of the valve body so I may replace it later. I was however able to replace the other accumulator piston on the valve body.
3) I did not enlarge any oil holes on the separator plate. Aside from one item that I didn't install anyway, instructions say that “you will be pretty happy” with the plate as is and enlarging some of the holes is optional. I can say that I fully agree. It shifts beautifully.
4) Trust the instructions, in that several of the spring replacements may be a bit shorter than the factory ones. This is to change the shift firmness and speed. It made me a bit nervous until I drove it.
5) The basic shift kit that dfc739 links to also includes some springs that are used for a valve replacements that don't come with the kit, and there are springs for parts in the pump which I understand requires removal of the trans to install. There are also springs for the 2-4 servo that I didn't replace (see #7).
6) In hind sight, I wish I had bought just the shift kit first to understand what other things I could have ordered to make it more complete. Then again, I'm not sure I would have fully understood until I had the valve body out.
7) I did buy, but did not install the Corvette servo. Time was getting away from us (5 hours to do this!) and since we didn't need to remove the cross member anyway to get at the pan, I decided not to bother with the servo. So there was a bunch of extra stuff in the kit for the 2-4 servo as well that didn't get used.
http://gmtnation.com/f93/how-remove-4l60e-valve-body-replace-plastic-accumulator-pistons-4972/
http://gmtnation.com/f24/built-4l60e-replacement-4894/
