First of all everyone at Jake's Performance would like to thank our customers for a great 2011!

I'm starting this post as a general auto trans technical post. Have a question you want to ask but are afraid to? Now is the time.
Have an advanced tech question about theory you want answered?
Hit us up!

I encourage all the other builders and vendors to jump in as well. Let's keep it cordial but maybe we can eliminate some of the voodoo by answering some questions here.

I'll try to answer anything that's not proprietary info.

 

ok, I will jump in, I have a Y2K SS with lot of bolt ons and Yank ST 3600 and 3.73 @ about 70 K miles ( with a complete dyno tune) lost the 3-4 pack a local well known trans shop did a complete rebuild ( what ever that included I do not know) everthing was fine ( shifting correct) about 500 miles I did a town cruse for about 2 hours and a lot of hot laping on the stall (ST 3600 Yank) at that time I had a fin and plate cooler and the OE cooler but no trans temp guage, the same shop did a partial rebuild at a reduced price the 3-4 worked fine worked fine, shift fine ( I think it shifted fine but not sure) after each rebuild I drive easy for 200 miles to allow breakin of new parts, after 200 miles find 2 nd gear is slipping, this time I pulled the trans myself and returned it to same shop which broke down and inspect again at reduced price, BUT the same shop say they CAN NOT find any problem, But the shop did install " THE VAC MODILATOR". As I was not sure the " VAC MODILATOR" was going to fix all my problems and as I did not want to keep pulling the Tran myself, at this time I was working part time a a Dodge dealership and a Old tech offered to rebuild trans for a cup of coffee I drove 200 miles to a trans wholesale supplier and bought 1000.00 in perfarmace parts at this time also installed an additional tube cooler with fan and also added a fan to the fin and plate cooler ,added a Trans timp guage to the deep pan and added a Yank SS400 after 200 mile to allow parts to breakin all gears shift fine no slipping of any kind, but at WOT the trans will DOWN shift from OD down to 3 rd Gear fine, BUT NOW to my problem- @ WOT the trans will not down shift from
OD to 2 nd gear not matter at which speed I stomp it, I had another shop run dianoist and the PCM IS comanding the downshift OD to 3 rd , but is not comanding the OD to 2 nd shift at any speed( my tune has not been changer since before the first trans rebuild
The tans temp with /without the OE cooler and both ext coolers will run 220-230+ if doing a slow town cruse at 10-20 miles per hour, A complete differant trans shop did a complete trans pressure check ( looking for the cause on high trans temp) and this shop stated the trans pressure was correct ( ?)

Mr Jake
Now please help me : why no downshift to 2 nd gear and why the high trans temp?
THANKS for any/all help
Johnny

 

I would need to look at a stock tune for a 2000 SS but I'm sure the lack of OD-2 downshift is the heat preventing the downshift.

My suggestion would be to get a IR temp gun and shoot the cooler lines going in and out and see what the temps are and if they coincide with what the PCM is seeing.

If so, the first assumption of heat is converter. It makes 95% of the heat in an auto trans anyway. See if you aren't getting lockup and if it's getting commanded.

 

I have no OD-2 @ ANY TEMP -cool or warm/hot, but if heat problem why no problem with OD-3 ?
I have a temp guage in the pan, and I have checked with TR gun on pan and is close to same as in pan guage, I never run hard untill temp in up to 100+ but it will not OD-2 at any temp

as stated I have pro dyno tune several years ago , have not changed any tuneing sence before the first rebuild, I do have LS1EDIT, I have OE tune and present tune , but have no ideal how to post them Here.
Any way I could e-mail them?
I will PayPal you reasonal fee for the correct answers

Thanks again
Johnny

 

If you look at your tune files, does it ever allow a 4-2 downshift?
If it's not commanding it, it won't do it.
You need to look and see if it will command it under any circumstance.

Isolate the reason. Don't assume it's mechanical.

Does LS1Edit have the capability to force a shift command or solenoid state?

 

"...does it ever allow a 4-2 downshift?"

I would think so as before the first rebuild it would down shift at any time with no problem

"..If it's not commanding it, it won't do it."
not sure where to look in EDIT

" Does LS1Edit have the capability to force a shift command or solenoid state"

not sure
I understand just enough about Edit to be in danger of fauling up the tune unless some one can explain which / how to change the trans files
as stated I have not changed any files sence before the first rebuild and it was down shifting before the first rebuild
I do not think it is it's mechanical
just do not know how/what changed in tune. also what do you think about the heat problem
Thanks Johnny

 

In HpTuners or with a good scanner you can command solenoid states or gear. You need to try this.
I think you have a tune issue.

The heat is most likely converter related, you need to check cooler flow, cooler efficiency (with temp gun) and if the lockup is coming on (stopping heat production).

 

i'll be building a backup 4L80e this winter, do the basic bushings, steels, clutches, seals, HD-2 kit, set clearances
i know there are some minor tricks to help shifting, like leaving out seals, drilling holes, etc, other than what the HD-2 kit calls for
if not prop. info, would be nice to see pics of some minor mods
thanks

 

I'll post some pics when I get to a computer.
Leave the center seal out of the direct drum, 2nd ring from the front off the center support, and plug the reverse feed hole in the case after the center support is in with a 3/8" cup plug. Instructions are shown on my website for a TH400. Same in all aspects.

This is dual feeding the direct drum. I also recommend drilling a .061" bleed hole in the drum as shown.

Drill the 1-2 feed hole in the plate to .096-.125", drill the 2-3 to .125-.140" OR don't drill at all and omit the checkball. Drill the 4th feed to .096". Block the 3rd accumulator.

Use a new boost valve and the stock PR spring for up to 700 HP.

No need to buy any aftermarket valve body kit with these mods.
Our kit makes some other changes for bigger power stuff and has a 3rd and 4th accumulator block off plate.

 

I'm having my 4L60E rebuilt. I will have the lock up deleted and obviously be going with a non lock up stall converter. I have the option of installing a manual valve body. Now my question is, will it shift harder and instantaneous than when shift via electronic(computer)? Is there any performance advantage to this? More durability, if any? Mind you that this car is a track only car. I appreciate any suggestions and recommendations, thank you.

 

Eliminating lockup on a 4L60E is going backwards IMO. A full manual VB is as well if you have the means to computer control it.
It will not shift any faster than a properly setup electronic shift. It will likely be firmer bit this isn't resolution a good thing.
I would reconsider what unit you are using if this is a mostly race setup.

 

I have a question about racing a race built TH400 with RMVB. I had the throttle stick with my t-56 after my run at the track. I turned the key off because it was on the rev limiter and nothing I could do. now that I have a TH400 in my car, if this happens can I turn the key off? I've heard you cant put it in neutral at high speeds it may explode. Just curious on a safe way to shut the car down in the middle of a pass when something goes wrong.

 

The most important thing is to safely get the car shut down. If you have to kill the engine, you do what you have to do. Once you do so, the trans will default to neutral and you run the risk of a direct drum explosion but its a risk not a certainty.
Chances are you will already be on the brakes slowing the car, and that's what you want to do, the slower the car, the less likely the drum is to grenade.

 

I've got a rvmvb TH350 that I took on trade & supposedly has a tci shift kit in it.. My question is, do I run a vac modulator or plug the hole for it.. I keep reading conflicting info on this. Thanks!

 

A RMVB should not need a modulator.

 

I'm moving my tranny cooler to under my bed with a fan. What cooler do you recommend for a 4l80e at around 700-800whp?

 

Ok I got a question for the class. When installing a TH400 bushing in either a TH400 or an 80E unit and using a TH350 pump bearing, which way do you like to install the bushing? When I say this I mean which way do you face the lube grooves in the bushing? Now keep in mind I'm talking about the lube grooves not the slots cut in the bushing. It seems to me for lube purposes in an 80E you would want to install the bushing with grooves facing the rear of the case. My reasoning is that the lube oil for the case bushing is coming from the lube tube in the rear of the case. With the grooves facing the rear of the case it would allow more oil to get up in this bushing. A few days ago I was talking with another builder about doing this mod on an 80E. In a Th400 I believe the bushing is installed the opposite of the way I'm thinking it should be done in an 80E. Not sure if it will make much of a difference on which way it faces but I figured I would ask you this question here for the sake of your thread! TIA Vince

 

I don't think it's critical, and on the early units the lube holes in the output shaft will lube the bushing.
I know some builders will claim the later units are better due to lube improvements but IME the early model is less likely to suffer a lube failure.
It does make sense to install that bushing with the notches up though, so the lube can feed into the grooves. Particularly on a late unit.

 

It looks like the optishift is setup to read tps as 0-5v. The issue I have is my WOT voltage is LOW (~0.8v), and idle voltage is high (~3.55v). The optishift wants/expects the opposite (low voltage at idle, high when open). How do I combat this?

 

Here's another quick question for you. With my rmvb race built th400, when i'm cruising around in the pits in 1st gear can you let off to come to a stop or must you shift to 3rd even at 10mph just so you can let off the throttle? or say i back it out of my driveway and drive in around my neighborhood can i let off at low speeds or must you get it into 3rd every time before you lift your foot off the pedal?