'96 Monte 4T60e transmission replacement, can't decide

[DChronos]

Hey all. I got 2 things to ask here. I apologize if it's a bit verbose.

 

I own a 1996 Monte Carlo LS, 3.1L, has a [6AFW] code transmission, 117,000 miles. Last week, I was cut off at wal-mart, put it in reverse and hit the gas hard, then there was a clunk and I lost reverse, and hear pieces moving around inside the transmission. I also hear a knocking / tapping when I start the car now, which goes away when I put it in gear, but comes back when I start driving more than 10Mph.

 

I know the transmission is shot, since I have no reverse gear and hear those pieces moving around inside when I start driving any faster than 10Mph, or in any gear other than 1st... I'm sure the reverse reaction drum / stove pipe is what blew, since it seems to be infamous for cracking, wearing, and breaking.

 

So I went to the local Grab n Go self serv junkyard to get a used transmission to replace this one with. I only plan to have this car for a few more years anyway, as it's got plenty of damage and busted parts that would cost more than the car's worth to replace and fix.

 

Here's the deal... I found 2 possible candidates that had bad engines that seem to have leaked oil, but the transmissions were good. There's just a couple things that make me wary, since this is the first time I've touched a FWD transmission, and this will be the second time I've replace a transmission.

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The first car is a 1997 Olds. Cutlass Supreme SL 3.1L, has [7AFW] transmission ID. It looks like it hasn't been taken care of quite as good as the second car, but it only has 117,000 miles on it. The engine clearly leaked oil, as it came down all over the transmission, and was labeled as engine bad, transmission good.

 

For the transmission, I removed the pan to inspect it as best I could, didn't see any obvious damage or wear, however, the pan, filter, and lines had a good coat of fine metal dust and a slight burnt smell to the fluid. The fluid color was still bright clear red, though, it seemed fine. When I rotated the right axle, there didn't seem to be any play in it before the left axle moved. The differential lube line going to the accumulator was tight in place in both its connections. When I reached up and messed with the reverse reaction drum / stove pipe, I felt firm trying to turn it, but I was able to slide it left and right with ease... I don't know if that's normal or not. It was also easy to turn the wheels.

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The second car is a 1997 Monte Carlo LS, 3.1L, and also has [7AFW] transmission ID. It looks like it's been taken care of better than the first, and it clearly had a major oil leak, much more than the first car. It was labeled as engine bad, transmission good. However, this car has 172,000 miles on it.

 

For the transmission, again, I removed the pan, and it looked much cleaner inside. There was much less metal dust particles, -barely- a burnt smell to the fluid, which was the same color as the first car, but the differential lube line felt very loose. I could pull it from the accumulator with little effort, and the other end felt loose and wiggled a bit when I turned the axle back and forth. I know this is an easy fix, though, and could just push it back in and secure it with a certain fix. When pushed back in, it was tight, like in the cutlass. There seemed to be a slight bit of play when I turned the right axle before the left axle moved, but barely.

 

Looking into the gears as best I could, everything looked great, and the reverse reaction drum felt tighter than the cutlass. I haven't tried moving it left and right yet to see if that's normal... but the parts looked cleaner. Also, there is a flat springy part that's in a hole right by the accumulator, with another part behind it, a lock thing with a pin against it... that part moves a bit as I turn the axle back and forth, but doesn't on the cutlass. When the differential lube line was loose, it also wiggled when the axle was moved back and forth.

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Again, I apologize for being verbose, I can't show any pictures.

 

Basically, I got a transmission from a 1997 Cutlass Supreme SL with 117,000 miles that had a slight burnt smell to the fluid and a good coating of black metal particulate on the iron parts in the bottom pan... and the thing with the reverse reaction drum sliding left and right easily... versus... a 1997 Monte Carlo LS with 172,000 that looks better inside, had a lot less metal particulate and less of a smell to the fluid... and a few other things I'm iffy on.

 

The one in the monte appears better, but it has 172,000 miles on it.... the one in the cutlass doesn't appear quite as good, but only has 117,000...

 

 

I got no clue what these things I described mean... if they are normal or not... if the one with 117,000 is worse off because it has more metal particulate and more of a burn smell than the one with 172,000.

 

There's also the deal with the torque converter... if the one with 117,000 is clearly better because of less mileage, or if the one in the 171,000 mile one could be better if it was cared for better. I wish I could get a history on these vehicles, it's racking my brain trying to figure out which one is likely to be the better pick.

 

 

Replacing this transmission is gonna be a big enough pain, I just want to make sure I get the best one. I don't want to pour that much more money into my car since it's pretty much a junker and I plan to only have it a few more years, that's why I'm just gonna use a used one for $100.

 

From your guys' experience, and what I described with each, could you tell me what you think is the better pick?

 

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OK, I got one other question, which is about my car... I'm sure the transmission is busted since trying to shift into reverse only results in a grinding sound and the engine freewheeling like it's in neutral, and the sound of pieces moving when driving down the road... I don't know if the torque converter is still ok. I don't know why I hear this rattling sound from my transmission when I start the car and I'm still in park, as I got no clue what's actually moving in the transmission when you're in park. I don't know why the sound goes away when shifting into gear, but returns and gets louder and faster the faster I drive down the road.

 

Could this sound be something other than the torque converter, and is there a way to check if the converter is probably good? I can say that my transmission fluid is now a darker red-brown color after the transmission broke, but it's been quite some time since I checked it. Last time I did, it was still a good light red color, I believe.

 

 

Again, sorry for being very verbose.

[mikedunbar]

I'm afraid I don't know which transmission you should use. I'm not an expert, but certainly many things are moving in the transmission while the engine is running, everything up to the parking pawl, plus all that fluid being pumped around.

 

What did catch my eye in your post is that you say you have a 6AFW. I am looking for the differential and final drive assembly from one of those. I wonder how far from CT you might be?

 

I have a 6HBW which I would like to convert to the quicker final gear ratio.

[Crazy K]

get a doner from either car along with the torque converter. the conditions of the lower mileage trans is not bad enough that you can't clean and service it. I've put 30k on a transmission that looked like that when opened up, i see the settling gunk as more of a sign that the transmission has not been operated in a long time, ergo the more recently ran the fine particles in the fluid will not have settled as much.

 

last but not least... whatever choice of transmission you choose, learn about accumulator upgrading to make the shift characteristic of the transmission better. I do it on all my cars to great result.

here you go:

http://www.w-body.com/showthread.php/74943-Accumilator-springs

 

and UPGRADE THE MAGNET. add a tiny button neodymium magnet next to the stock magnet and you'll notice which is better on your next service.

[DChronos]

Thanks for the info. I ended up taking the trans from the 1997 Monte Carly with 172,000 miles since it seemed better cared for, judging by the fluid being in better condition and the parts feeling firmer when turned.

 

I'm replacing the left/right axle and pump seals, and already was replacing the vacuum modulator with a newer adjustable one. Also replacing the filter and might add an external cooler.

 

I got to see inside my busted transmission, and sure enough, the reverse reaction drum blew apart. I found 2 teeth in the pan, but it looks like 8 are still inside the transmission... a good chunk is missing from the right side of the drum, and the leading edges definitely were worn away before it busted. I also found pieces of some pink plastic thing in the pan, one being cube shaped.

 

On a side note, I discovered that whomever serviced this car before I had it forgot to put in a corner oil pan retaining bolt... what moron could not notice the big hole where it goes?? It's no wonder it's leaking oil out all over the bottom. It's also a wonder the bolt stayed sitting on the subframe in front of the left motor mount all these years.

 

 

To mikedunbar: I live in IA, so that's a long ways away, and I'd be willing to bet the differential and final drive teeth got hit by the missing reverse reaction drum teeth still up inside my transmission. I could hear something grinding as I drove. Sorry about that.

 

 

I have another question I'd like to ask... after drainging all the fluid from dropping the pan and changing this transmission, I was worried about there being air that may have gotten trapped up in the system and wondered how you'd remove that, if there's a a bolt or something one could open to let excess air escape, or something else one could do about it.

[Crazy K]

you mean drain air from the transmission? lol you run the transmission and it pushes the air around inside.

 

TIP: when bringing a transmission to life that has not been used for who knows how long... don't sit there and beat on it first thing. Idle the engine to warm, and then shift it into each respective gear. once you have done that take it for a gentle drive and you should have everything evenly warmed up with all the fluid flowing before you ask much more than mild throttle from it.

[DChronos]

Yeah, I was already gonna be gentle and go through all gears. There's no telling just how good this used tranny is, so I want to be careful. Then I'll double check the levels and all.

 

What I mean is, I drained all the fluid when I took the pan off, save for whatever is in the valve assembly and all that, but if air bubbles got up into the valve assembly from sitting for a long time without the fluid in the pan area, or from being moved around and sat on it's end or anything, would the system push that air out on it's own? It won't pump into the torque converter with no way to escape or anything like that?

 

One thing I'm more worried of is air going into the torque converter when there's no way to refill it. So far, I've just taken the torque converter off and set it off to the side on it's back end (the side that attaches to the flywheel) and placed rags over it to keep the dust out. Some fluid has slowly pooled in the bottom of the shaft hole, though. I hope it's good at keeping all it's fluid inside.

 

 

 

For now, I've got an oil pan gasket to replace and oil pan to re-torque to stop that leak while the subframe and old tranny is out.

[Crazy K]

LOL relax. the transmission fills all it's parts and the air comes out.

 

 

Let me put your mind at ease:

 

Engine running car in park is when the fluid level is checked, right? yes, the fluid will have filled all the cavities and even the torque converter.

 

Engine off, the fluid level sits higher on the stick. All you can do it check the appearance and odor of the fluid at this time. The fluid drains to the low point it can in all the cavities and the torque converter as is normal.

 

 

AND.... if the engine was running and the car does not move, you check the tranny and see you have too much fluid on your stick, your transmission is not pumping it's fluid...

 

 

now you know.

[budboy315]

hey, just wondering does the junk yard you got that other transmission from still have a 4T60-E for sale? i need one for my 99 lumina but im stuck down here at keesler Air Force Base in mississippi and cant find one around here and need one. if they still have it could you get me a contact number for them so i could possibally purchase it and have it shipped here if the price is good?? thanks for your help

-AB Jesse Spangler

[19Cutlass94]

I dunno about all that, but when someone says transmission replacement, I always say 5spd.

[DChronos]

To budboy: I live up in Iowa, and this is a pull it yourself junk car lot... they don't pull anything or ship anything. Gonna have to try elsewhere. It's a pretty common transmission for GMC cars in 95-97, as far as the list I got shows.

 

 

I got the transmission all replaced and checked out. It seems fine, but I'm still working on the shifting and adjusting the new adjustable vacuum modulator. At times, I feel it clunk a bit from first to 2nd gear.

 

Am I thinking right that you turn the screw COUNTER clockwise to reduce hard shifts and shift up at lower RPM? (What does that really mean, shift at lower RPM?) So far, it's seemed to reduce when going counter clockwise, and felt harder going clockwise. The modulator was a red stripe one... I didn't know there was other colors and spring tensions till I already had this installed it.

[RobertISaar]

the modulator on a 4T60 and 4T60E does not control shift points, only shift firmness. the TV cable on the 4T60 and the shift solenoids on the 4T60E control the shift points.

[DChronos]

TV cable? Where's that?

 

And am I right in that counter clockwise smooths shifts and clockwise firms them?

 

I'm wondering about stuff, cause it just feels like I have to have to push down a but more on the gas to get moving the same speed as well as to shift to the next gear than I used to. I could swear it shifted to the next gear at lower speeds on my old transmission, and got me going faster a lot quicker.