Hi guys. Thought I'd put this one out to the masses since I am totally in the dark when it comes to trannies.

I have a 95Z that has had some work done to it before I bought it. Mostly bolt-ons, but also some head work and a mild cam. The original 4L60E slagged last winter and I got a replacement from a local F-body boneyard with 27k on it.

The PCM has a PCMforless tune job. The tranny has a B&M 28k gvw cooler up front instead of the radiator lines. It also has a Yank TT 2800 converter.

Now the problem. Sometimes it runs fine, sometimes it feels like there's no tranny there at all. From what I've seen, it runs great when I first turn the car on but runs for crap not much later. Since I am new to using a converter, I have a hard time telling what is slip versus what is just not running. But when i'm gunning the engine to 3000+ rpm and not moving, it's obviously not the converter. I should note that there also seems to be a slight leak from the "top" line where it meets the tranny. Very light though.

LUCKILY, this is not a daily driver. But I do want to get it sorted out now so I can enjoy the summer and the T-tops. Since it seems to work fine one day and then for crap the next, it seems to me that the clutches and gears ought to be ok. But perhaps the pump is dying? If there were no pressure inside, then it would make sense that the car wouldn't move sometimes and then work fine when there WAS pressure, right?

So far, that's all I've got. If you guys come back with questions or info, I can see what else I can learn and respond back to you.

I really appreciate any help with this, since I don't want to bring it to a tranny shop and have someone just say "Yeah, we need to rebuild it for $2400" and get taken for a ride if its something simple. Likewise, the cheaper the better since I'm really over budget on the car already and an expense like that would sink me for the year.

Really though, thanks for any help with this. I can tell you when a carb is rich or lean by ear, but trannies (automatics, anyway) are like the devil's children to me. LOL I just hope mine ain't dead!

 

And just to clarify.... when it works, it WORKS. With 3.73s, a 355 and the Yank... the rear tires cry for help in first gear at the slightest pressure. So to go from "great ***** of fire" to "don't touch me, I have a headache" seems strange. I've had trannies die on me before, but it was always either a gradual thing where the 3-4 shift started to clunk, or the thing just went all at once in a flood of tranny fluid. I've never dealt with it where the whole thing is perfect today and totally crap the next. And by next day, I mean like two weeks later. That's about how much free time I have to drive my cars these days!

Edit: And on a final note, what and where is the absolute CHEAPEST rebuild or used replacement I can get? I would do it right if I had the dough, and plan to in the future. But for this season that's not feasible and I just want the car to work.

 

A GM rebuild has a warranty and is reasonable. The have several options also.

 

I was reading in the Drivetrain forum (where this should be) and saw that it isn't necessarily proven that you can just run a tranny cooler without taking it throught the radiator first or having an electric fan on the cooler itself. You may want to invest in a temperature gauge and see what kind of temperatures the transmission is generating. They're definitely going to be higher with the stall and not going through the radiator. Maybe that explains why it feels good at first (cold) and then starts to fade away (hot). You can only get it so hot before the clutches start to go.

 

REASONABLE????

$3333 is what I was quoted to rebuild mine. (Yes $3333, I found that slightly odd also). Then I paid CSS to build it... and you WONT find a better built 4L60E.

 

Talk to Frank in the drivetrain forum. He might be able to give you a little advice.

 

Let's start with the obvious...What kind of condition is the fluid in? Is it brown/black? Does it smell burnt? This may be a sign that your forward p9ston is cracked, or your input sprag is failing. Both are common problems with the 4L60E (in stock form).

$2400??? Gee, maybe I should raise my prices...LOL Our top of the line "Pro Race" transmission is only $1400.

Frank
CPT

 

Ya get a reman over the parts counter.

Ya can get a built racing tranny for 2500.

 

Thanks for the info. The pricing at that MD place looks decent. Wish I had known of them when I was working down there all last summer.

I had a thought, and while I doubt it's the case I'm curious just the same..... could it be the "limp home mode" on the PCM? Does anyone know how that affects a tranny?