Transmission Swap Tips

[Ross Love]

Okay, first of all im not quite sure how fast this forum is but I would appreciate it if someone could help me relatively quick seeing that I will be trying to perform a transmission swap this weekend when I go back to my hometown for Memorial Day weekend.

So my transmission in my 1994 Oldsmobile 88 has been having some issues. About a year ago, in the cold mornings the transmission would not go into gear when I selected "Drive" from park, it would sort of just sit in neutral. But if I put it into "1st" it would grab and go into gear, then I could switch it into "Drive" and the car would be able to drive fine. At this point, when the car was in gear, it would shift flawlessly up and down, and never had a hard shift. Also, when the car was warm, I could shut it off for maybe two hours, and if I came back out to it when it was still a little warm, it would shift back into gear from park after sitting, but if it sat overnight, it would not want to go into gear.

This whole problem was intermittent, sometimes in the morning it would go and sometimes it would not go. I would say I had a 50% sucess rate. But as time went on, it became harder and harder to get into gear in them morning, and it would take a couple more seconds for the car to even go into first gear.

Now, my car will not even shift into first gear really, I can sometimes get it to shift if I let it warm up, then put it in gear and rev it a little, but I dont do this often.

The transmission fluid level was low when I checked it about two months ago when I was having the worst problems with it (this was probably the reason this was happening), so i brought it into Aamco and they did a fluid flush and refil, to no avail.

So at this point, I want to go to a junk yard and pick up a cheap transmission to swap in this weekend when I travel back to Portland so that I can have a car at college... But i want to know what transmissions will be compatable (aka what years and models) because there is a chance i will not be able to find an identical car at the junk yard. Where will the part number be on the transmission, and do they have to match identically for them to be compatable?

Also, I was wondering if this will be a basic unbolting, pulling, and swapping the new one in (along with the possible linkage and plugs and axles etc.) Or am i going to have to drop the engine, or unbolt anything crazy like subframes etc.? I am mechanically inclined and shouldnt have any problems doing this, but I may be alone when I do it, and would like a couple tips if possible on pulling it.

Which gaskets should I replace when doing it? And I think i remember hearing that there are high pressure lines going in and out of it, do i need to flush the system or do i just disconnect, then refill later?

Thanks in advance for any tips or help! And wish me luck!

[MagicRat]

Before you do anything drop that transmission pan!!!

Shifting and performance problems are like this are often caused by low fluid pressure due to a clogged filter. In my experience, a fluid and filter change along with a pan cleanout will fix the problem about 50% of the time.

Yes, I know you had a trans flush. This kind of service does nothing to free-up a clogged filter and nothing to clean out a pan. IMHO these services are misleading to consumers and are pushed onto customers mostly because it is a quick, easy, high- profit service that mechanics can easily sell to consumers.

Regular (every 3 years or so) transmission filter and fluid change (where the pan is dropped and cleaned out) is MUCH more useful in maintaining a transmission than a flush.

Drop the pan and take a look. A modest amount of friction material and dirt (dark grey debris) in the pan is normal. However, if there is lots of it, your filter may be packed solid and not allowing fluid to flow, thus causing your problem.

In my opinion, new fluid, filter and gasket may work. It's cheap and easy to do and imo worth a shot before you get wrapped up in a transmission change. If you do this, drive the car for a while, to make sure that any lingering debris in the trans gets flushed out.

If you do the swap, definitely get a Haynes or Chilton service manual to show you what to do. It's a big job with many different steps involved... some of which may not be immediately obvious. It's dangerous too, if you do not know what you are doing.

Among the unusual steps involved, you have to support the engine from above, by chaining it to a 2x4 wooden bar that you have to cut and fit so it rests on the strut towers.

You have to unbolt the front struts so you can get the driveshafts out of the trans before removal. You must mark the strut location on the steering knuckle, or else you will be doing an alignment afterwards.

As for transmission compatibility, the wrecking yard can take care of this. They should have a Hollander Interchange manual (or software) that tells them what other transmissions will fit. Ask them to see their copy of the manual to be sure, if you have any doubts.
There are many minor differences between years, and even within the same year of car, so it's best to let them look after finding you a compatible one.

And finally..... good luck!

[Ross Love]

Thank you for the super quick response.

I will replace the filter and clean the pan. But I will likely reuse the fluid that is basically brand new because I am so extremely broke (College student status). ATF is UBER expensive, i think it will cost around $70 to buy new stuff, which is almost as much as a used tranny from the junkyard this weekend with the half off sale for Memorial day. Call me ghetto, but its more like broke.

Thanks for the tips about unbolting the struts. I think ill just put a jack under the engine to support it. And ill rent a manual from the library too.

My biggest worry will be actually taking the transmission off of the engine after it is unbolted, im not sure how i will do this by myself without just kicking it off and damaging it. Do you think that if i also put a jack centered under the transmission after it is unbolted that i could gently lower it? This is probably what i will do.

Also, are there any special tools that i will need? Do the axle bolts need a special head? Ive got 12 point stars or whatever that worked on my VW axle bolts, but will i need something else for these?

I will be doing this by myself because all my contacts are out of town, but im pretty mechanically inclined (in the middle of an engin swap in my VW) im kind of looking forward to it.

Oh, and my impact gun is going to be my friend this weekend

[thisnametooktolong]

1994 hmm, is that a 4t60? Or a 4T60-e? Pretty sure it is an E, OBD I just ask the junkyard what the cross is. Because they made some changes to the temp sensor back then and that can toss a wrench in the mix because of the different wiring harness (that can be changed with the sensor) I think the easy way would be to stick with a pre-96 OBD I car, GM used the 4t60 E starting in 91 and everything by the mid 90s. and they used a higher stall TC/TCC and shorter chain drive ratios in the sporty cars. That can cause some problems (read below) Because you mention that you will have to find it in the junk yard I assume that you will pull it. If you can just take a battery saws all and cut the frame rail out if it is in the way (again read below). It saves a lot of time

1.) I would like to say that I am no tranny guy, but I have muddled my way through a rebuild or two
2.) I have never ever seen a GM product with a long-term slip respond as expected with a fluid and filter change. (But I knew this guy once with a friend that did)
3.) I would not recommend using the wrong tranny and swapping wiring harnesses but it can be done with the 4t65. And they only used the HD version behind the supper charged cars
4.) They made the trannies in two versions standard and heavy duty, and a few gear ratios. Some times this can be a problem because the ECM Thinks there is a slip because the engine RPM and the VSS does not make sense to the ECM. That is not usually the case on OBD I cars. But if it does happen, there is not a darn thing you can do about it without re-programming the ECM (chip swap). That will cause a MIL
5.) Some place back there they made a few changes to the frame. The ones that are next to the transmission and have about 2 or 3 inches of clearance to the frame will come straight down without a lot of trouble. The ones that are very close, and the frame lower require one of two methods. 1.) The book says to yank the driver’s side suspension and frame rail. Then remove the tranny. (About 3 hrs depending on rust and where on earth is that bolt holding it.) OR… you can scoot the engine over as far as you can and tilt the tranny end down and pull the tranny that way. I prefer this method because you break way fewer bolts and don’t spend the time replacing them in the rust belt. Especially the ones under the driver’s door. This is still about three hrs of hand wrenching the (the first time) BUT it depends on the car because some (like a Beretta just don’t have the room)
6.) On the engine toward the passenger compartment there is a bolt that goes from the engine and screws into the tranny. The easy way to get that bolt is with about 3 feet of extensions but you may have to remove the engine mount that is in the way. The clearance back there just plain old fashioned….. sucks!
7.) When you have the tranny in, make sure that you adjust the gear selection switch. Underneath the shift arm is a switch that is black. If you look closely at it, there are two notches that must aligned perfectly, in neutral. Or you can use a scan tool to make sure that it is getting the correct signal in the correct gear selection. (But I am not sure if you can do that on the 94). generally speaking the P/N safety switch is touchy compared to the gear selection for the ECM, so if you turn it till it starts in N and it wont start any place ells besides P it should be OK but suspect the alignment if you don’t have first. (make sure your back up lights work)
8.) I know that you said that money is an issue BUT! Spend the extra on new output shaft, input shaft seals, and change the filter. The money it will save in the long run is worth the extra doe (40-50$) also when installing the pan make darn sure that mating surface is nice and flat as well as true. After getting shipped around they tend to bend. If it is slightly off it will leak and I don’t care how much black RTV you use.

[MagicRat]

Originally Posted by Ross Love

Thank you for the super quick response.

I will replace the filter and clean the pan. But I will likely reuse the fluid that is basically brand new because I am so extremely broke (College student status). ATF is UBER expensive, i think it will cost around $70 to buy new stuff, which is almost as much as a used tranny from the junkyard this weekend with the half off sale for Memorial day. Call me ghetto, but its more like broke.

Thanks for the tips about unbolting the struts. I think ill just put a jack under the engine to support it. And ill rent a manual from the library too.

My biggest worry will be actually taking the transmission off of the engine after it is unbolted, im not sure how i will do this by myself without just kicking it off and damaging it. Do you think that if i also put a jack centered under the transmission after it is unbolted that i could gently lower it? This is probably what i will do.

Also, are there any special tools that i will need? Do the axle bolts need a special head? Ive got 12 point stars or whatever that worked on my VW axle bolts, but will i need something else for these?

I will be doing this by myself because all my contacts are out of town, but im pretty mechanically inclined (in the middle of an engin swap in my VW) im kind of looking forward to it.

Oh, and my impact gun is going to be my friend this weekend

Before committing yourself to reusing the fluid, look at the pan. If it's full of debris your 'new' fluid is already contaminated and is useless.

Also, take the effort to support the engine properly as I described. This allows you to leave all the hoses , exhaust, wires etc attached.

If you just support the engine with a jack, then it will fall off when you pry the transmission loose, and may rip/damage all those wires and hoses (and might possibly fall on your head, too )

[Ross Love]

Originally Posted by thisnametooktolong

If you can just take a battery saws all and cut the frame rail out if it is in the way (again read below). It saves a lot of time.

Hell yeah, I have a battery powered sawzall! Ill cut the entire front end off the car if i have to!

Originally Posted by thisnametooktolong

Some place back there they made a few changes to the frame. The ones that are next to the transmission and have about 2 or 3 inches of clearance to the frame will come straight down without a lot of trouble. The ones that are very close, and the frame lower require one of two methods. 1.) The book says to yank the driver’s side suspension and frame rail. Then remove the tranny. (About 3 hrs depending on rust and where on earth is that bolt holding it.) OR… you can scoot the engine over as far as you can and tilt the tranny end down and pull the tranny that way. I prefer this method because you break way fewer bolts and don’t spend the time replacing them in the rust belt. Especially the ones under the driver’s door. This is still about three hrs of hand wrenching the (the first time) BUT it depends on the car because some (like a Beretta just don’t have the room).

Thanks!

Originally Posted by MagicRat

If you just support the engine with a jack, then it will fall off when you pry the transmission loose, and may rip/damage all those wires and hoses.

Okay, ill support it from the top with a chain and 2x4 or try to borrow a cherry picker from a friend.

Any word on what head the axle bolts take?/ Any other special tools? Im just saying this because im used to working on VW's and there are special tools for just about anything (suspension etc.)

[thisnametooktolong]

GM uses 36 mm on full size cars, and I think 32 on the rest with the same tranny. they also use a 28 (i think) but they anly go on small cars with the itsy bitsy TH 125 metric (I think). The only funny tools you realy need is the three feet of extensions. that and iether a pry bar and/or vice grips to hold the flywheel and turn the flywheel when you pull the TC to flywheel bolts.
By the way you will find that when using a cherry picker the legs will be in your way of crawling around under the car..... Not fun. You may rather use a 2X4 stretched from fender to fender with a piece of carpet over the fenders. Then use two heavy-duty tie down strap to the engine on the tranny side one to the strut bar and the other to the 2X4. Each strap has to hold up 1/4 the weight of the engine. so you are right on track on that one. I have used jacks/stands for the engine but then you are moving around the jack all day. for the strap way, you also wait until after you have all the bolts out accept the mounts.
This way there is nothing in your way and you can crawl around with the engine supported. Back in the day I use to use a floor jack to lift the tranny in, but a 4 wheeler jack stand works great with a piece of plywood on top. And some bailing wires to hold the TC all the way in if you are going to lift the tranny in place with your chest and arms. To line up the tranny (especially if lifting with your chest and arms) it makes it a lot easier if you get some long bolts with the heads cut off. This way you can let the tranny hang close as you take a break or get on top to muscle it in.
I am not sure if you where being funny when you said that you would cut the hole front end off, just remember that saws all is only for the donor car. and yes I have had to cut off the hole front end because the car kissed a pole at a rather high rate of speed.

[Ross Love]

Haha, yes I would be using the sawzall on the DONOR car. Ive already had to take the front end off my car when I got in a head on collision because my frame rail was bent.

So, for the axles... There will be a bunch of bolts holding the axle on the transmission side, then there will be one nut on the hub side? This is how my VW is...

And for dropping the front suspension, im just going to unbolt the struts on the strut towers so the suspension can drop down and give me enough room to pull the axles out?

Oh, and by the way, thanks for the quick responces, I posted a thread on The Oldsmobile Connection, but all of the guys over there are pompous, and that forum is pretty slow. This forum is pretty fast (Still not as fast as the VW forum I frequent )

[thisnametooktolong]

No: the inside CV joints are held in place with a spring clip. just place a good sized pry bar between the trany and the CV joint and lightly tap the CV joint with a hammer.To reinstall, just hold the entire half shaft as straight as you can, aligned inside the tranny, compress the joints by leaning into the car holding your weight with the Half shaft. Then if it still does not snap back in..... just tap the end with a BFH. Don’t smack the inside CV with a hammer unless you remove the boot first..... it will cut the boot.
Faster to do than my 63 beatle or 68 baja was

[Ross Love]

Okay, quick update on the days progress (not quite as much as I would like, but still good)

I started at 10 by going to the library and renting a copy of a Haynes repair manual (I hate Haynes and Chilton but praise Bentley's).

Next I went to a U-Pull-It and found two 1994 Eighty Eights and neither had an analog odometer, both digital so i couldnt see how many miles were on them. Also, the shifter inside was not on the "tree" but in the middle where a stick shift would be, so this gave me some hesitation to start pulling. But the transmission codes on the oil pans matched the one on my oil pan so i assumed they would be okay, i think it was the 4X60 - E.

So i started to pull it, made some good progress for like an hour and a half, but didnt have a big enough socket to take off the hub nut @ the wheel.... AND i didnt have an extension (short enough) to get to a couple of the transmission mount bolts that are up past the subframe. I managed to kick a set of two wheels and tires under the engine snugly so it wouldnt drop on me, but this was useless, i didnt get to the step where i needed to drop the subframe because i didnt have all the tools. At this point, i called it a day at the wrecking yard and went to get a transmission filter from Schucks Auto Supply.

I know my day was backwards in the sense that i should have done the filter first, but i had little faith that it would fix my problem. But i got one, and a pint of transmission slip/ leak fixer. I pulled the pan (pain in the ass because there is no drain, im sure you guys know) and cleaned it up well. Next, i tried to figure out how the filter came off, by looking at my new one, i knew that there were no bolts or screws holding it in place, and the only thing holding it would be the plastic neck in the female end of the transmission. So i wiggled it back and forth, and pulled but it wouldnt come out. So i pulled REALLY hard and... SNAP, the neck just broke off and the entire filter did a cannon ball in the 7 pints of ATF, and the fluid went in my eyes and mouth

I also gashed my thumb open when this happened on something, i probably need stitches, but ill probably just glue it.

At this point, there was still the plastic neck lodged up in the female part of the transmission, so i cracked and pulled on it with some side cuts and vice grips until it all came out. I couldnt get the old O-ring out, so i left it in because it looked like it was still in good condition. I put the new one in and put the pan back on, and poured the ATF back in (still looked pretty good).

I tried to blow through the old filter (yuck i know, but it had to be done), and it felt pretty clogged which was nice. I started my car up and cycled it through the gears after it warmed up and at first it didnt go, but after a few times back and fourth slowly from Park to first and back, it went into gear and i could drive. Im not sure if it is fixed yet, i suppose i will know tomorrow morning when the car is completely cold and i try to put it in gear, but ive got my hopes up.

I need to shower.

[thisnametooktolong]

I Take it that when you saw what was involved you said "O shoot"! By the way I don’t mean to kill your optimism, but of course you can’t blow through the oil soaked filter like you can a dry one. The fluid is probably 2000 times thicker than air. About that o-ring. That was not a good idea but you can probably get away with it. Just don’t do it next time. In any event it was not a good idea.
How much crud was in the pan? That little square magnet does not hold much crud, but did it look more like a black fuzzy jellybean cut in ½? That is probably going to be the big killer, lots of crud in the pan spells disaster. I know that you had it flushed, but that does not get much off the magnet or the thick stuff off the bottom of the pan. I do understand why you are giving it a shot….. Heck I have done it many times. Right now I have 2 cans of magic goop in my car along with a filter change and it is running. But I am keeping my eye out for a sweet tranny in the junkyard.

About that slip problem. Because you decided to try the filter thing, you may want to try a quart of transX stop slip/stop leak. It will either help nicely after a few miles, or not work at all. Later, you may find that although it does get the thing moving again, it may suffer a sudden catastrophic failure. That is because it will make those paper thin glazed clutches and bands stick together for a while. But as soon as all the material is gone, it will stop like a lawn mower over a pipe. Had the same thing happen to a Ford. The turkeys did not tell me that they had been adding stop slip/leak @ 1 a week for two months. I changed the filter, and output seals. The car ran great for 2 or three days and stopped like a broken CV joint.
Needless to say that is what I did today…. played musical tranies in a Taurus. The music is still playing and I hope I will finish it by noon Sunday. That way I can take the rug rats fishing.
PS,
I thought that I was the only one that just butterfly myself back together. I carry supper glue in my traveling tools and keep a package of 4 in my role around. Some one to help hold it together and a little toilet paper and you are good to go! It also helps getting those nuts and bolts that you cant see or hold on to start. Just glue the bolt to your finger, and then stick it in the hole. ( don’t think that came out right)

[Ross Love]

Yeah, I forgot to mention that I did put a quart of anti-slip/ leak protection in the car.

Well, I just started it up, let it warm up for a minute, and it went into gear! If this actually worked and its not just the fluid i put in, then im gonna baby this car for a while until i can sell it. No more burnouts in the rain

Now the real question is, do I want to risk it and drive it 120 miles to college

Ill let you guys know how its driving today and tomorrow. But thanks!

[Ross Love]

Oh, and on a side note, the ATF didn't blind me! I was afraid that I would wake up today and not be able to see because I got a s#it load of it in my eyes yesterday, but i can seeeeeeeeee hahahahahahahaaaa

[thisnametooktolong]

Yes, I know what you mean. Transmission fluid is a little caustic. For some reason I have been in it a lot this spring. Its hard to keep your hands out of it when you are pulling a pan. In fact my hands are so ruff right now: If you place a micro fiber hand towel flat on a table, then I place my open flat hand on top of the towel. I can pick up the towel without closing my hand.
About the eyes, they are resilient. About 25 years ago I had a charger/booster hooked up to my Hurst Olds rag top. I had my head over the fender and had a friend hit the key. All I remember was seeing a spark fly off the battery post, and then having a stainless steel Random orbit sander taken to my face. Eyes came through fine and still have 20/20 vision, pock marked face ended up baby smooth, Auto-Shack paid the hospital bill and sent me a check that purchased my First Yamaha V-Max. And just think I did not even remember signing some papers that an Ambulance Chaser had me sign when My eyes where bandaged.
You see, car batteries are not explosion proof, but Auto-Shack did not fight it.

So well any who…….. how is your tranny doing

[MagicRat]

Thank you for the update.

Your old filter was DEFINITELY clogged up if all that ATF came out when you removed it. Normally, good filters allow much of the ATF to drain back into the pan, so you only get a 1/2 pint at most coming out when you remove the filter.

Now, do you really have two O-rings holding that filter in?? All the trans manuals and service procedures I have specifically recommend against doing that because it places the filter pick-up too close to the bottom of the pan, possibly impeding flow. The old O-ring should come out.

But is it runs okay, forget about it, especially if you can sell it.