Well, the earleir trannies are a little easier to work with. Basically, removing check balls (restrictions) applys some clutches and brakes quicker making for a more firm shift. Many of the apply circuits use what si called an "accumulator" which is a piston and a spring under it. This removes the shock o softens the shift. Installing a weaker spring or in some cases, removing them all together makes the shift harsher giving you a criper shift and maybe even stratching a gear. But this real harsh shift can sometimes brake lose the glues that hold the friction materials to the clutch or brakes and band. Also, slippery fluids can be repalced with a more sticky fluid like the Ford Type "F" or even more sticky is the B&M trick shift. Also, line pressure can be bumped up by just adjusting the throttle pressure cable. This will bost the pressure and make for a firmer shift. The idea behind the throttle cable is to boost the holding ability to keep the clutches and brakes from slipping under a heavier load. I didnt really read what they installed. Liek you mentioend, they didnt go into too many details. I'm sure they dont want you to do it yourself, but to send them the $$$ and have them do it.

 

I have heard of the Type F trick before. I was worried about using it on a newer tranny. On older GM cars you can put that stuff in to get a firmer shift, but just changing the pan fluid doesn't work you have to replace all the fluid.

 

Sonnax makes a replacement boost valve and sleeve assembly that is supposed to correct some shifting problems (soft shifting and delayed reverse):

http://www.transmissionspecialty.com.../97855-23K.htm

I've found it online for $27.21 at:

http://www.transmissionpartsusa.com/...00%2D09785523K

To install it, you need to drop the valve body, but it looks to be a relatively straight forward job otherwise.

I haven't used this product but am considering putting one in when I change my solenoids. If anyone has used this product, I'd be interested in hearing your opinion on it.

 

Funny you mention tightening the downshift cable because I remember that when these valve body upgrades were getting debated someone had suggested doing just as you mentioned and he had claimed it worked very well. The issue was that not many people have really had a chance to dig into the trannys (on a technical level anyway) so the understanding is pretty limited (thus why these 2 shops, IPT and Level 10 more or less have a stranglehold on the tranny mods in general......I will say John over at IPT is a stand up guy though and does great work, just not cheap).

Are you guys over at the dealership rebuilding trannys in-house or are you sending them out to a 3rd party?
.......or do you only install new/refurbished from Toyota?

 

Well, we all are factory trained, but getting rusty. We used to do all our own in house ATM rebuilds, but its too time consuming, ties uip too much work space when disasseble waiting for parts and the labor hours was low enough, it wasnty too profitable and of course, not being able to test run them before hand. Toyota came out with their own reman program, and we use that now. We dont do anything more to them other then the regular DIY kinda stuff. I guess it came down to profitability. It wasnt there.