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Newb (Who Can Learn) Rough Shifting Tranny Help
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DrAnonymous
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PostPosted: Sun Jan 06, 2008 1:48 pm    Post subject: Newb (Who Can Learn) Rough Shifting Tranny Help Reply with quote

I was given an 86 Chevy El Camino, with the OD tranny. It runs ok and needs some TLC, for 90K miles. I was hoping to get some good advice from you all here on the tranny.

It shifts very hard when upshifting. 1 to 2, 2 to 3, etc. I'd say it slams into gear, but that may be a little harsh. Its not smooth at all, but it always shifts.

When stopping, it seems like the RPMs are going down too far, near engine stall. When I take off again, it cycles 1, 2, 3 like it should.

Can someone educate me some?

- Is the hard shifting a sign of a tranny failure soon?

- I was told that changing the fluid of a worn tranny can cause it to fail if it was already close. Is this true? I was thinking of doing a fluid flush, to ensure the TC got new fluid as well. Also a filter change, if this tranny has one in it.

- It looks like the vacuum lines can affect this, but I haven't learned enough. Is this true and if so what maintenance should I go ahead and do regardless (hoses, sensors, etc)

Any help would be greatly appreciated! I am a car newb in my mind, but I can learn. I did learn to do the CV axels for my dad's car. Smile

Regards,
DrA>
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Big Dave
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PostPosted: Sun Jan 06, 2008 5:33 pm    Post subject: Reply with quote

You didn’t mention which AOD you have so I will assume a 700R4 (and not the newer computer controlled 4L60E that replaced it). If the tranny has a shift kit and has been modified for racing (such as different weight or springs on the governor, shift kit with a modified or aftermarket valve body), even the TV cable being out of adjustment could cause problems with the smoothness of your shifts and when they happen. I am also going to assume since you are on a performance oriented board that you like a crisp shift that occurs above the stock shift point.

Changing the fluid will never cause a transmission failure. Please do change the fluid and the filter, paying attention to what you find in the bottom of the pan and the condition of the fluid. So far as what is wrong with it? I would first look to a defective accumulator with this transmission as it will produce symptoms similar to what you are describing. I would also trace back the ownership if possible to se what had been done to it prior to you buying it. This may be this trannies normal mode of operation if it was set up for the track to drag race only. The vacuum line if it has one is to tell the tranny what load the motor is under so that it can effect shifts to accommodate the motor. A missing vacuum line could be telling the tranny that the motor is running wide open and shift as fast and as hard as you can, but that is not normal for an OD, that uses a TV cable to tell it this info (or TPS if electronic).

Big Dave
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clay
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1972 Chevrolet Nova

PostPosted: Sun Jan 06, 2008 7:38 pm    Post subject: Reply with quote

I have heard of fresh fluid causing a failure, and I can actually see it happening under certain circumstances (very neglected, overheated fluid that has deposited a layer of varnish everywhere, fresh fluid sort of cuts everything loose), however at this point, you need information, and the only place you can get it is in the pan as Big Dave mentioned. There are several things it could be. Broken accumulator springs can cause harsh shifts, but this wouldn't affect every gear change. Line pressure needs to be checked to see if it is a problem with the pressure regulator valvetrain in the pump causing excessive pressure and harsh shifts. Since you mentioned is trying to stall, as a long shot it could be something wrong with the lock up converter circut or the converter itself causing a partial lockup condition. Converter slippage helps with cushioning shifts too. Let us know what you find in the pan. Clay
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DrAnonymous
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PostPosted: Sun Jan 06, 2008 11:59 pm    Post subject: Reply with quote

Big Dave wrote:
You didn’t mention which AOD you have so I will assume a 700R4 (and not the newer computer controlled 4L60E that replaced it).


I poked around and used the info from this site Chevy Tranny ID to determine I have an THM200R4, this is based on pan shape. Physically, the tranny has the following connections:

- Left side front: Shift linkage to steering wheel
- Left side rear: 3 wire plug (wires are very brittle and copper can be seen on one of them)
- Right side: speedo cable, tranny fluid lines
- 'thingy', which goes to the throttle linkage on the carb

Left is as driver sits in vehicle. The pan has the word metric stamped into it. I also used this site to decide.

Big Dave wrote:
I am also going to assume since you are on a performance oriented board that you like a crisp shift that occurs above the stock shift point.


(Start gratuitous sucking up) Actually, the entire car should be stock, since it was never modified to go above standard performance. I opted to ask for help here, knowing that tuners and hardcore folk such as yourself would know far more than people on other forums. I can also tell from the details of the posts, people have alot of experience in things out of the ordinary, raising the bar on people's expertise. (stopping sucking up)

Big Dave wrote:

Changing the fluid will never cause a transmission failure. Please do change the fluid and the filter, paying attention to what you find in the bottom of the pan and the condition of the fluid.


I double checked the fluid level and its fine. The fluid is a nice pinky/red with no burn smell at all. I haven't pulled the pan, busy all day, but I suspect it won't show any shavings or metal particles.

What are the names and purposes of the 3wire plug and the 'thingy' on the other side?

I also did more testing, by manually shifting the tranny.

- Going from 1 to 2, a hard shift, but not as much as when in D
- Stopping while in 2, with the column on 2'nd, the car will stall.
- Stopping while in 2, with the column on D, the car almost stalls.
- If stopped, car idles fine when switching to 1 or 2 on the column

Is it time to drop the pan and report more info?

Much thanks!

DrA>
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DrAnonymous
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PostPosted: Mon Jan 07, 2008 12:03 am    Post subject: Reply with quote

Big Dave wrote:
Changing the fluid will never cause a transmission failure.

clay wrote:
I have heard of fresh fluid causing a failure, and I can actually see it happening under certain circumstances (very neglected, overheated fluid that has deposited a layer of varnish everywhere, fresh fluid sort of cuts everything loose), however (snip...)


Is it likely that pulling the pan and doing the filter will cause me problems?

DrA>
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10sec.et
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1969 Oldsmobile Cutlass

PostPosted: Mon Jan 07, 2008 1:07 am    Post subject: Reply with quote

DrAnonymous wrote:
Big Dave wrote:
Changing the fluid will never cause a transmission failure.

clay wrote:
I have heard of fresh fluid causing a failure, and I can actually see it happening under certain circumstances (very neglected, overheated fluid that has deposited a layer of varnish everywhere, fresh fluid sort of cuts everything loose), however (snip...)


Is it likely that pulling the pan and doing the filter will cause me problems?

DrA>



its usually the neglected, high mileage transmissions that die after a filter kit or fluid flush. from your description of the fluid condition and mileage, i wouldnt be afraid of a filter change. actually, i think its a good idea so you can see whats in the pan. if work is slow tomorrow, i will see if i can dig up any info on your symptom. would like to know if theres metal in the pan though.

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It seems we can look at our magical Balls and come up with a fix?

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Big Dave
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PostPosted: Mon Jan 07, 2008 7:48 am    Post subject: Reply with quote

DrAnonymous wrote:
(Start gratuitous sucking up) Actually, the entire car should be stock, since it was never modified to go above standard performance. I opted to ask for help here, knowing that tuners and hardcore folk such as yourself would know far more than people on other forums. I can also tell from the details of the posts, people have a lot of experience in things out of the ordinary, raising the bar on people's expertise. (stopping sucking up)

What are the names and purposes of the 3wire plug and the 'thingy' on the other side?
Is it time to drop the pan and report more info?

Much thanks!

DrA>


You are welcome!

Yes dropping the pan is the only way to get to the internals.

The wires are for the lock-up that keeps the torque converter from slipping while in OD to extend parts life and improve mileage greatly.

The ‘thingy’ is connected to the throttle so that the transmission knows when you have the foot stomped on the gas for your "passing gear" which is really the tranny down shifting into a lower gear based upon the difference in engine RPM and what gear you are currently in.

There is something wrong already, or using the technical term "it’s broke" so you have nothing to fear by dropping the pan but the expense of the fluid and a transmission filter kit.

Though I suspect unless you contemplate performing the rebuild yourself (requires time, a few specialty tools such as snap ring pliers and spring compressors, and access to a lot of compressed air for cleaning and testing, and a rebuild kit including new steels), you would be better taking this into a repair facility (other than a Brake-o, or tire shop) for a rebuilt replacement or a rebuild of your unit. To give you an idea of what a custom built ready to rock and roll well built tranny would cost you look in places like Jegs, or Summit for an entry level (as close to stock as you can get) replacement from some of the transmission rebuilders such as B&M or TCI. That way if they start say anything excessive above that price (plus shipping which is occasionally free) you will know when you are being scammed. Bear in mind the tranny sold by Jegs or Summit does not include the price of a converter which you can buy at NAPA or Advanced/Discount Auto. You will want a new one anyway so get that price as well (metal particles in the pan circulate through out the tranny including the converter), so if the tranny shop does not include that in the rebuild price question why.

You can rebuild a tranny (unless your local city codes object to you dropping a tranny on a city side walk) with a book and some effort. It is not as easy as bolting in a catalogue replacement, but with a little effort and care it can be done. Unless you are a gear head I think a catalogue rebuilt might be your cheapest but it depends upon where you live and the level of trained techs looking for work in your area (we are entering a recession again) so people are getting antsy about finding work to keep their shop doors open.

Big Dave
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DrAnonymous
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PostPosted: Tue Jan 08, 2008 9:48 am    Post subject: Reply with quote

I did some more test driving last night and isolated the stall problem to 2nd gear only. IE, if the selector is in second and I go to stop, the car will stall. Any other setting and the car seems ok.

I changed the fuel filter and air filter, since they both needed it. It helped some in the smoothness of the acceleration.

It was raining last night, so no chance of doing the pan. Sad

10sec.et wrote:
if work is slow tomorrow, i will see if i can dig up any info on your symptom.


Any luck on researching?

Cheers - DrA>
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10sec.et
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1969 Oldsmobile Cutlass

PostPosted: Wed Jan 09, 2008 10:00 am    Post subject: Reply with quote

DrAnonymous wrote:
10sec.et wrote:
if work is slow tomorrow, i will see if i can dig up any info on your symptom.


Any luck on researching?

Cheers - DrA>


not yet. i havent been able to get free but i havent forgot about you.

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It seems we can look at our magical Balls and come up with a fix?

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MufflerBearings69
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1968 Ford Galaxy

PostPosted: Wed Jan 09, 2008 10:02 pm    Post subject: Reply with quote

Slightly off topic but here it goes-

I am still a bit inexperienced and new and have gone through an AODE from a Mustang on my own successfully, I would recommend getting factory service info if you can (I bought the Ford AODE book on eBay for ~25 bucks- factory books rule!)

I dont know what level of mechanical aptitude you are at, and whether you would want to venture into the transmission on your own... Not to sound discouraging but it is a bit tedious! Do pay attention to pricing and what guts are going in- You can price an alto red eagle brand kit for your trans online, and it is absolutely NOT more work to rebuild with than stock stuff, at least on the AODE.
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DrAnonymous
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PostPosted: Sun Jan 13, 2008 4:44 pm    Post subject: Reply with quote

I got time to drop the tranny pan and didn't find much excitement, at least to me. Smile The filter appears to have small metal flecks in it, but no shavings. Everything else seems to be normal, nothing lose or obviously goofed up. I've attached some photos for those who know more than me.

What should I do now? I need to put it back together so I can drive it for work tommorow. I wanted to wait long enough to see what y'all had to say first though.

Cheers,
DrA>



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DrAnonymous
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PostPosted: Sun Jan 13, 2008 4:46 pm    Post subject: Reply with quote

The rest of the pics. Smile

What are folks opinion on installing a drain plug into the tranny pan? I can't weld one in, though my neighbor might be able to help me.

The wires in the TCS plug show copper, where can I get a new end to splice on? How do I get the plug seperated? I tried pulling and pushing a bit, but couldn't see the release well enough to get it. I'm afraid I might break it and then be in a world of hurt.

DrA>



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Big Dave
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PostPosted: Sun Jan 13, 2008 5:04 pm    Post subject: Reply with quote

I agree nothing obviously wrong. Could be a broken spring (not likely, or a blown seal - much more probable) that is causing a variation in line pressure internally. The grey dust areas in the pan are the asbestos fibers from your clutch discs mixed with burnt (rusted) steel off of the driving plates. You can see one of the clutch packs (it doesn’t look worn to me) in your "Tranny" picture.

The TH tranny can be rebuilt in your driveway as mentioned it requires a modicum of tools, patience, and help from a book or some one else who knows what they are doing to supervise. Faster and easier to buy a rebuilt "crate" tranny from a mail order house, or as a last resort to have yours rebuilt by "experts".

It is the expert approach that worries me with the level of skill declining in the industry as people who have done this sort of work for thirty years retiring and young guys who saw a simulation of a repair last week taking over. But they all have to learn some where, some time if they are going to stay in this profession (it is their commitment I question more than their skill).

Big Dave
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10sec.et
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PostPosted: Mon Jan 14, 2008 12:25 am    Post subject: Reply with quote

sorry i wasnt able to get you any useful info. the trans "experts" we use just want to overhaul them so no help there either Rolling Eyes . as Dave said, i dont see anything serious in the pan. looks normal. if you want to fix it yourself then you definitely need to get a good book or two. i have Ron Sessions book on the TH350 trans and its about as close to a step-by-step guide as you can get. do some research, he may have one on the 200R4.

drain plugs are helpful if you have to pull the pan off with the car on jackstands and dont have room to fit the drainpan and yourself under the car at the same time. hopefully you wont need to pull the pan off very often. i dont do filter kits on my cars anymore. i just flush the fluid so i dont have a need for a drain plug.

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clay
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PostPosted: Mon Jan 14, 2008 7:04 pm    Post subject: Reply with quote

Everything in the pan looks fine. The clutch pack Big Dave is talking about unfortunaltely is the low gear pack and it pretty much never shows any sign of wear at all. It gets engaged when the car is moving still and engine is at idle and all it does is disengage when it changes to second. I would bet a broken spring somewhere. Seems like the 200's were bad about breaking a spring in the pump called the priming spring. The 200 and 700 use a variable displacement vane pump. If line pressure drops, it shifts part of the pump to increase output to keep pressure up. Once everything stabalizes, it decreases volume to cut down on drag, wear, etc. There is a spring that pushes this outer pump ring in addition to line pressure. I can't get my head around what could be causing it to act funny in the manual "2" postion. Sitting still, it's still in low gear and not moving. In manual low (and reverse), it raises line pressure and if anything I would think it may cause a slight idle speed reduction there if any. The next thing I would do is get a pressure gauge and check line pressure in every gear at minimum and maximum TV. Maybe something will show up there to point us or somebody in the right direction. I agree that I don't think you need a rebuild though, it just has a problem that needs to be fixed. 200R4's aren't really complicated, but they are aggravating to get apart and back together. It in particular is full of snap rings that will try your patience. I may be rambling, just thinking out loud. Clay
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