I am rebuilding a 4t45e. I'm wondering if there are any tricks or parts I should consider for performance. Raybestos blue clutches are no longer available so OEM is all there is. I found a link on the net about a guy who dumped a bunch of money into one but nearly all those parts I either wouldn't need or are no longer available. Any wisdom would be appreciated.

 

I was told by another member that the torque converter ZZP has for the 3800 cars would work with ours. I'd verify with ZZP first though. Other than that how about an LSD? Those are $750-1500 new though.

 

Many of the 3800 torque converters are the same as our so I will look into that, thanks.

My differential will be welded, no limited slip needed.

 

Trans star carries blues and Raybestos carries reds

Full synthetic fluid is a must and I run a secondary Trans cooler to help keep Temps ice cold.

 

I called Raybestos yesterday. They never did make the red clutches. They had an old part number for the blues but it was listed as an obsolete number now. They even called several vendors that might have still had one in stock for me and none of them could remember the last time they had them.

I got my OEM rebuild kit today from Transtar. They confirmed that performance clutches no longer exist. They had all the old part numbers, they knew exactly what I was talking about. They can't get them since they aren't made any more though.

I was planning to run a big dedicated cooler with its own fan.

 

So what else is there to upgrade then?

 

That's odd because I talked to them over the summer and this is what I was told they had.[IMG][/IMG]

 

welded diff? in a fwd? and just how do you plan on turning?

 

Sometimes there are upgraded drums, sprags, pump shafts, etc. In fact, the Raybestos catalog lists some different sprags that may be upgrades that I'll have to look into. I was hoping someone here would say, "Yeah, get the upgraded sprag!" Sometimes there are also internal valve body mods that can be done. I also wish I could find some chromoly output shfts but I think I am going to have to have some made. :-\

Great find! That isn't in their normal catalog. I will call them today and find out about it!

This is going in a rock buggy where the dif acts more as a 4x4 transfer case than an axle. If it wasn't welded I would have FWD or RWD but never 4WD. Once it is welded I will have full-time 4WD which is exactly what I want.

 

Another question I hoped someone here might know something about ...

As I was tearing my donor Cobalt down the shifter had 6 positions on it:
P
R
N
D
I = automatic selection of gears up to 3rd gear.
L = automatic selection of gears up to 2nd gear. Or in other words, L gives you first gear until the computer decides you need 2nd and then shifts for you. There is no way to hold the trans in 1st gear against the computer's will.

However, once I had it torn down I noticed that the transmission and Range sensor themselves have a 7th position beyond the shifter's L position. I assume this is the first gear position which you are hardware-locked out of using the factory shifter.

I have a buddy who is using this same drive train in a buggy similar to what I am building and I talked to him about this. He wasn't able to keep a manual 1st in the L shifter position and once I told him about the 7th position he disconnected his shift cable to see if he could put it in the 7th position and get manual 1st gear. Unfortunately, he wasn't. The car acted exactly as if it was in L, giving him 1st for a brief period and then going to 2nd. So obviously the computer is preventing a manual 1st gear. I hypothesize that simply disconnecting the range sensor might give him a manual 1st in the 7th position but he hasn't had time to play with that yet. I don't think this would be a long-term solution even if it worked though.

So my question is this: Does anyone know exactly where in the transmission tune you would modify to make the computer allow you to lock it into 1st gear?

 

I called raybestos direct today, spoke with Irvin. R600100 is not a clutch kit or even an individual clutch pack. It is a single clutch disc which they have 600 in stock. However he believes that the only reason they have it is because it is used in another application. Because there are literally no other red clutches available for the 4t45e any more:

r600110 - direct clutch disc - obsolete - none in stock anywhere in the US
r600120 - intermediate clutch disc - obsolete - none in stock anywhere in the US
r600130 - coast clutch disc - obsolete - none in stock anywhere in the US
r600140 - reverse clutch disc - obsolete - none in stock anywhere in the US
R600100 - forward clutch disc - current part number - 600 in stock throughout US

He said red would have been the high performance level clutches and blue would have been extreme performance. He confirmed that they did at one time make the blue clutches which is what Transtar lists but they do not make them any more and he sees none in stock anywhere in the US.

Yesterday when I was talking to Transtar we were looking up part number RCPS-29, which was the blue clutch kit. They said it was obsolete and there were none in stock anywhere in the US. But what I didn't see yesterday is that they also list individual blue clutch plate numbers, so I called back today:

14104AHP - 2nd clutch plate - obsolete - none in stock anywhere in the US
14106AHP - direct clutch plate - obsolete - none in stock anywhere in the US
14108AHP - Forward clutch plate - obsolete - none in stock anywhere in the US
14110AHP - reverse clutch plate - obsolete - none in stock anywhere in the US
14112AHP - coast clutch palte - obsolete - none in stock anywhere in the US

I wish I was wrong.

 

On for info

 

understand the welded diff now. i have heard of this sort of application, it all makes sense now.

as for the shifter and manual low, its really just another position. the pcm programming wont allow the trans to hold in 1st gear, its designed that way to prevent damage. gm originally designed the 4t45e to be prnd321, however in later years (starting around the time the cobalts came out) they switched to prndil. the pcm isnt programmed to read the last detent. you may be able to program the pcm to get it to hold manual low, im just not sure how..

there is another method of controlling the transmission for full manual operation. basicly you use toggle switches hooked to shift solenoid a and b and turn them on and off in the correct shift pattern, this has been done in race applications. the only downside is you have no automatic mode, its full manual all the time, and you always are running max line pressure

 

Well, I spent all of today rebuilding my 4t45e after welding the differential inside. Everything was going smooth until I installed the sprocket support assembly. It didn't want to seat all the way. I spent 6 hours tearing everything down and putting it back together what seemed like 15 times, none of which that bitch would go on. I was about to give up and decided to give it one last try and for some reason it literally just fell into place on its own. Then I tore a valve body gasket which ended the whole operation. >:-[

 

Any progress is good progress. Keep us updated

 

How much do you actually know about this? I've read about it in the GM Performance Handbook as a method to eliminate the TCM and it is an option that I have considered. I haven't found anyone that knows much about it though. For instance, could I leave the TCM in place, control the shift valves manually, and let the TCM continue controlling the TCC and pressure?

 

ive read about it, never tried it though. knowing how the software in the tcm works, i doubt it can be used just to control line pressure. what happens during a shift is the tcm will request torque reduction from the ecm (through dropping timing or decreasing throttle angle), it will back of the line pressure, command the solenoid change, increase line pressure and tells the ecm to turn off torque reduction. this all happens very quick. now the tcm is monitoring how long the shift takes from the time its commanded to when it actually sees the gear ratio change via the input and output speed sensors. if it happens too slowly it will increase the line pressure during the next shift in that adapt cell, too fast and it will lower it (works much like fuel trims do). when the transmission is worn out it will set a code p1811- max shift adapts. this happens when the tcm can no longer compensate for the wear in the transmission (kinda like a lean or rich code). the tcm defaults to max line pressure when the code is active

now assuming you can shut the shift solenoid codes off and the tcm would still function normally, what would happen would be the tcm would command a shift, and it doesnt happen it will start maxing out the shift adapts because it thinks the transmission is slipping and you end up with max line pressure shifts. the tcm also wouldnt be commanding the correct line pressure at the right time, it might be preparing for a shift and dropping line pressure when you have your foot in it and that could result in slipping.

 

Well my buddy took his rig to a tuner yesterday who claims that he was able to program a manual 1st gear. He still needs to take it out and verify ...

 

Does anyone make chromoly output shafts for the 4t45e? I didn't think so but then I saw that ZZP makes one for the 4t65e so I figure maybe I'm missing something.

 

typically the output shafts in the 4t45e arent a failure point. the 4t45e can only handle so much power before other components in it fail, and the tranny can only be built up for so much power. i really wouldnt be worrying about the output shafts breaking.

the 4t65e and 4t65e hd can be built to take a pile more horsepower, the race build is whats used with the 1450hp ecotec race engine.

 

soooo ... no one makes it?

 

not that i know of.

 

Here is the place one of the HHR guys got his red pads from a while back. May be worth contacting them to see if this stuff is still available for the 4t45e. For the link, copy/paste and replace all the "D" letters with "."

http://wwwDimportperformancetransDcom/gmautofwdDshtml