Weird Trans Problem

[citoboy_7]

Hey everybody, i'm working on a 95 monte carlo.(3.4L)

I swapped out the 4T60-E trans for another 4T60-E
Off a 98 Buick LeSabre

First off, the Monte Carlo trans was running fine, but was dumping trans fluid from the input shaft. (Driver apparently ran it hard even after it lost the fluid from there and destroyed the bushing in the torque converter) There was the tell-tale blackish crap in the oil, so even though the trans seemed 2 run ok still, this is the reason i swapped the trans

The LeSabre trans was very clean (the car was running great, and was involved in a front end wreck (did not damage anything more than cosmetic), so was parked and used for parts. Everything is identical with the exeption to the side pan, which is used as a mounting point on the monte's pan (i used the monte's) and the shafts (also used the monte's)

ok, so the details. The pan also had another difference. The LeSabre's had i believe 6 bolts on the pan around where the cv-shaft goes in. in order to use that pan, i also had to swap the shift solenoids and pump (all integrated) The monte's uses a o ring, no bolts around the cv-shaft area.

So here's where it gets funny. I got everything bolted up and ready, fill the trans, check everything again. Start it up, runs fine. Goes into gear fine, shifts fine when driven, at first at least. Then driving down my little street, it'll drop into 2nd or 3rd, and refuse to shift out of it. I can put it in neutral, park, back into D or OD, and still goes to 2nd or 3rd (not sure which, but it's really weak) and won't get out. If i turn it off, start it and put it into D or OD again, It'll start in first, but shortly after, again drop into a higher gear and again refuse to shift. Any ideas? Did i forget something?

One other thing i forgot to mention, I suspected The shift box that sits on the shifter (on the trans) but tried both the original, and the the LeSabre one (which is identical, with the exeption of the wire that carries power to the starter, and with a little creativity, i connected it, but it worked the same.

Also as a side note (i don't know if this has anything to do with)
The owner apparantly made a "cool air intake" with the tubing you can buy at autozone, and there's a black vacuum tube that is connected to the side, runs accross the intake (under the black plastic over the injectors) to the center left of the engine. It also runs around the driver side of the engine, around the egr electrical stuff, between the intake manifold and firewall, where it appears to go nowhere! O.o i taped that sucker up, cuz it was just open! The owner actually mentioned the car didn't want to start right away usually. I didn't start nor drive the car b4 i worked on it, but it starts right up for me, so i suspect he was running that open as it plugs into the intake tube, on the engine side of the Mass Airflow Sensor. Which makes me wonder if there's possible damage if he was running it lean this whole time... but does anybody know where that vacuum goes? like i say it's sorta just hangin there...

Lengthy, but i tried to include everything i've done, i know, and etc info. I appreciate any knowledge, info, advice!

Thanx

-Aaron-runaround

[whtbronco]

On the tranny shifting it sounds to me like the ECM is sending a limp home mode signal. I have seen this several times on my mom's Cadillac's. They will select either 2nd or 3rd gear and stay there so it can be driven, but not very well. Course they will also shut down cylinders. It certainly sounds like an electrical issue to me. I wonder though if it could be a vacuum issue, not sure if these tranny's even use vacuum like my beloved Ford C6, my guess is they don't. According to my Haynes manual it does have a vacuum modulator so I would check that and make sure the engine has 13-17 inches of vacuum pressure at the manifold.

I have no idea on the potential vacuum line off the intake tube.

[maxwedge]

The pcms and solenoids may not be compatible from 95 to 98. Look into that area also.

[troy1]

All the shift solenoids should be the same, TCC PWM solenoid might be different. I think what is happening the the TC is locking up on you. Does it happen right after the 1-2 shift? Does the can bog down and the engine won't rev?

[maxwedge]

I believe the programming form 0bd1 to obd11 98 is different and it is possible the communication is being lost, a full scan with a trans function scanner will more accurately diagnose what is happening here.

[blazes9395]

That tranny my not work properly for a few reasons.

When you changed the oil pump, did you change the valve body, or the channel plate, or both? The lesabre and the monte have differnt channel plates, different springs loads, accumulator springs etc, etc. You have to change the whole channel plate along with the valve body/oil pump. The reason why its not shifting is becasue most likely a mismatch of internal parts.

Also when you get past this problem, the '95 monte has a final drive ratio/rotor of 306/30 ( 33/37 sprockets drive/driven), the stall speed is 2060. The Lesabre will probably have a stall speed of 1897, different final drive ratios and when the PCM in the monte senses the differnt drive ratios it will most likely set the SES light and not allow forth gear up shift, along with no TCC lockup. The '95 monte does have a diffent TCC apply strategy then the lesabre, so that could cause slip codes because of different convertors used in those years. So this will give you something to start on at least.