Well finally had some time to work on this again. It's been sitting up on my lift since the last time I posted. I've changed out my leaky headers to new ones with copper gaskets, installed new PS pump, rack and hoses, new TPS. Also purchased a GM Tech 1 scan test tool w/ memory module.

Also cleared all DTC's and retaught my TPS with my tech 1

So, hooked up my tranny pressure gage this morning and as per the GM service manual, connected my tech 1 scantool and ran the PCS control program that steps the PCS. At idle in park at 70F tranny temp everything looks great, pressure steps properly per the chart in the service manual as the miliamperes go down. Also at highest miliamp reading pump puts out a steady 75 psi. Also put tranny in reverse and boost works OK as pressure goes up to about 150 at idle and back to 75 in other positions P,N,D, etc.

So then I notice tranny temp is at about 107F...not hot at all, and I try the step procedure again and the pressure pretty much stays at 75 psi, I did notice that the actual milliamps tend to be somewhat higher than the called for. I wonder if the new PCS motor is defective? Also when shifting into reverse no more boost

I can't see how only a difference of 27F would cause the pump output to drop so drastically. I'm wondering if the AFL valve could be binding up when the valve body warms?

Any insight on this would be helpful from the experts...thanks in advance

 

OK, replaced the PCS it with my saved GM stock unit. Didn't have a new tranny pan gasket so waiting for the red RTV gasket sealand to set up before refilling and testing

 

Hi guys

Filled her up this morning and same problem with my old PCS

I think it's the pump I reassembled with rebuilt (refinished) pump case halves I put in with a new 13 vane pump with hardened steel high speed rings and new stronger single slide spring.

I bet they sold me a polished piece of crap, then again, I only paid $75 so I got what I paid for.

I think my only recourse now is to pull the tranny out and install a new pump and also dig back into my beast torque drive input drum and replace the forward clutch return springs that I should have done in the first place.

Note the photos you were refering to is from disassembly. I actually installed a pinless accumulator and yes I did install the ball bearing plug using the old pin where the pin opening is located.

BTW, I have the Z-pak 3-4 clutch pack and wondered if I should put back in those 6 return spring pairs...they're out right now.

Also, where can I purchase a fully assembled high performance rebuillt 13 vane pump 1995 4l60E PMW (one piece case) with all the whistles and bells ( 0.5 boost valve, high speed rings, high rev slide spring, etc.) for a reasonable price?

 

Pete?

 

Ordered a new pump from GMpartsdirect $326 + shipping

 

Dropped my exhaust and drained my tranny fluid after work tonight

Hopefully I'll pull the tranny out tomorrow night...my new lift and tranny jack makes it a snap

I'll keep you all posted of my progress

 

Tranny is out!

Tore it down tonight

Tore the input torque drum down...all the seals look fine.

Overrun, forward and 3-4 clutches and steel look new of course...they are!

Took apart the pump and noticed the rotori s quite a bit thinner than the raceway....measured the difference with a straight edge 0.012" way too much clearance That's my problem...period

No wonder pressure would drop as the fluid thinned as it got hotter...just like the oil in your engine when it gets to 150F it drops from 60 to 25 psi

New pump on order should fix this...in the mean time I'll change the forward clutch release springs to the stiffer ones.

Some performance questions:

With the 3-4 Z-pack, should I leave out the 6 dual return springs?

Should I install a new 13 vane rotor kit in my new GM pump...its on order too?

Should I install a 0.50" boost valve in the new pump?

Is there a specific size O ring for the converter seal to input shaft...yhey all looked the same (I have the small shaft).

Any performance tricks or pointers would be appreciated befoe I button this thing up again probably some time next week would be appreciated....don't want to have to open this up again without some good hard fun time in between

 

Yes. Absolutely leave out the 6 dual return springs
No, do NOT install a 13 vane pump. I mentioned earlier that they are trouble.
.500 boost valve-Yes
Yes the o-ring on the input shaft is specific, although I do not have the size recorded. I order them 10 at a time.

Replace the large pump o-ring and all 7 pump bolt 0-rings. Also do not reuse the paper gasket between pump and case.

 

So I assume you agree with my diagnosis on the pump?

And thanks for all the answers to my questions Pete

 

As I mentioned in the e-mail, pump rotor and pump slides seldom vary more than .001. .0005 istyoical with .001 on the high side.
I am confident that you found your problem.
Aftermarket 13 vane pumps are about the only parts that are consistantly problematic. They are prone to break above 6000 rpm as well.

Glad to help

 

Wow, then I really got hold of a lemon!

Probably was my own fault though.

I took what I thought was a good 13 vane pump assembly out of my scored pump and put it in the refinished pump case halves with new stator from the california tranny parts seller.

If only I would have dry checked the parts for fit, I would have seen the problem right off the bat! Pure inexperience on my part

I'm going to use the new GM pump right out of the box, only thing I will alter is to put in the 0.50 Transgo boost pump. I may be tempted to open it up and replace the slide spring and also the rings with the high performance ones I purchased though.

One question, while I've got the "Torque Drive" input drum torn down....remember I had only changed the 3-4 return springs to the transgo stiffer anti-centrifugal ones. Should I change out the forward return springs, or should I put the 3-4 set back to stock?

Sorry for all the questions, but I don't want to yank this thing out again anytime soon, although I'm getting pretty good at it

 

I would install the springs. That combination works well.
I would also swap the factory gm pump rings to a hardened set. Pump ring breakage is pretty common. The pump slide spring swap is a good idea also.

 

Thanks for the valuable advice Pete...will do

One last thing, do you use a carbon band?

Any preference here?

 

I normally use kevlar or the alto red. For some reason, kevlar bands are receiving negative internet press. They have worked well for me for years. Never a band failure(yet).
I did install a carbon ato wide band on my own trans that is currently on the bench. I put quite a few parts in it that I normally never use. I am thinking about running it hard for a year and tear it down just to see the results.

 

Well, this afternoon, rinsed off my input drum and goodies, except for the clutch packs in mineral spirits and blew all dry, then reassembled everthing with all the correct new stiffer springs and air tested all...perfect.... All clutch packs work perfectly at 40 psi with no leaks (if you know which holes to cover ).

Noticed that the wide carbon band was a litlle beat up from dissassembly so I ordered a new wide Alto carbon fibre band.

Almost forgot, I have to send my converter back to pro-torque for a freshening prior to this assembly

Later

 

I presume that the wide band was installed on a new drum?.
If not, it is best to use a standard width band. They tend to burn on the edges if you put new band on old drum. This negates the benefits of running wide, and loosens up the servo pin apply after it burns in.
Although you probably know this, I added it so that when this comes up in someones search, they will see it too

 

It's been awhile since I posted all those pictures

Yes, I put in a brand new wide reverse drum and wide band previously

 

So I finally get what is shown as the pump assembly in the GMPartsDirect.com catalog for a 1995 chevrolet corvette automatic part #5 in the schematic drawing labeled as pump assy.

I received only the front 1/2 of the case with the pump guts included.....rear half of the case w/ stator is missing??

I paid $262 + shipping for the cheap (front) 1/2 of a new pump??


So this is what I did last Saturday, since I received only 1/2 of a new pump

Took the new GM front pump half and removed the new 10 vane pump guts in it's entirety. Measured rotor and slide thickness. Took my new 13 vane pump internals and measured slide and rotor thickness.....they are within 0.001" of the GM internals...great!

Sorry Pete, I like the 13 vane pump and it hasn't given me problems in the past.....just a preference

So I put the new 13 vane pump guts in the new front case also installed the single high speed slide spring and high speed forged rings.

Married this to my refinished remanufactred used rear pump body that has a micro finished turned flat face that I'd swear is a good as the new GM from case finish.

This also has the 0.50 transgo boost valve......also checked to make sure both pressure and TCC valving assemblies in this pump 1/2 operate freely.

Buttoned up the pump and torqued the bolts to 18 ft-lbs.

Also changed my pump and input shaft one piece teflon seals again and resized them.

Installed my new alto red wide band (didn't like the looks of the new carbon band I had in before...too fragile, very easily marred during removal and assembly). Reinstalled my input and reverse drum and then the pump. Filled my refreshed protorque converter, lubed the converter hub and installed my converter on the tranny. Then primed the pump with some tranny fluid pourd down the pump intake turning the coverter to suck in the fluid.

Reinstalled my gaskets and valve body, filter, turned my old force motor adjuster 1/3 turn clockwise and buttoned the pan up with a new gasket.

Will start putting it back in the car this week.....hopefully it's finally fixed

 

Finished putting it all back together last night, dumped my engine oil and stuck in a new filter

Filled her with fresh synthetic engine oil and royal purple Max ATF this morning, started her up and the shift from P into the gears sounded great...like it used to.

Drove her to work 46 mls to Manhattan this morning and it drove fine.

Tranny hovered at 203F in 78F ambient during some stop and go traffic...coolant was 192F, oil 212F

No problems so far

I'll eventually stick the pressure gage on it, but I'm having too much fun right now

 

Guess you aren't around tonight Pete