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Transmission Swap

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Firstly,

Hello everyone! It's been a long time.

My poor Pathfinder developed an issue shifting from first gear and I had to park her and move to daily my more reliable (albeit way less fun) car. Since then I have been watching her collect leaves, sap, ants, and other detritus but I declare that the time for action is now. She is getting fixed! 

 

This means that I am going to replace the transmission with one from a newer Nissan to help with future durability as she is now going to run as a weekend trail truck. Ideally I want to find one of the coveted HD transmissions. I have done tons of searching and reading the forums here and just wanted to ask a few clarifying questions to anyone who might know an answer. What I am looking for is confirmation that my first choice in transmission donors should be:

 

2001 - 2004 Frontier 4WD - VG33ER

2002 - 2004 Xterra 4WD - VG33ER

 

...followed by:

 

2001 - 2004 Pathfinder 4WD  - VQ35DE (Second choice due to extra work in required bellhousing/ torque converter/ flex plate swap.)

 

IF that seems correct, can I then go out on a limb to say that it appears by looking through the Xterra factory service manual I can use the VIN to quickly determine if it has the VG33ER engine, 4WD, and automatic transmission? I assume I could do a quick check for the Frontier FSM and determine the same?

 

IF all of that adds up also, does any have an leads on where to locate such a donor? I have several Pull-A-Part  locations near me (I'm from NW GA) but of course without going there to physically check the lots I'm pretty much just blind guessing. It seems to me like I'll have to settle for one of the non-HD VG33E 4WD automatic transmissions and just be happy if it works. The plan is a straight swap, possibly a stop by the transmission shop for a rebuild on the way home. I am conflicting with myself on this as I say that just having a transmission worth rebuilding seems good enough for the present time. Engine rebuild (keeping the VG30E) comes next, with a good look at the transfer case and differentials, as well as suspension components, etc. That's all followed with a winch bumper and possible suspension lift. I currently run 31x10.5 tires so I dont see switching up to a one inch taller tire doing much help, but I could be swayed later. Regardless, a little feedback before I go this weekend to scour the junkyards would be nice just in case I am missing something.

 

Thanks!

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I would hate to have to pull one of these trans/tcase assemblies at pullapart.

I got a used trans with the tcase attached for $600 at Givens Junk Yard in Lawrenceville. It was literally flawless. Best shifting trans of any vehicles I’ve ever been in. I tried to destroy it, and with great success I was able.

The next transmission I got was from Lance Used Auto Parts also in Lawrenceville. It had 50k more miles on it and I think I paid $700, or $550.. can’t remember. It’s not flawless like the first but it’s a solid transmission.

Givens and Lance both guarantee their transmissions for 30 days which is plenty long enough to know whether it’s going to be a good one or not.

If the trans from pullapart is bad you have to pull it back out yourself, take it back, pull another one which may also be bad, and put it back in again. That’s worth the extra cash to me...

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When the trans let go in my 93, I was down to having only 3rd gear left when I found a local shop that quoted $1500 to rebuild it and that included the R&R. Best price I had found before that was $900 + core for a rebuilt one in Arizona. For the cost of shipping, I had figured borrowing my brother's Subaru and doing a road trip taking the dead trans down and bringing the replacement back. Would have been half the shipping costs. When I got the quote, I figured the $600 difference with more warranty was worth it. When they got the trans torn down, they called me to come in and see the damages. Wound up costing an additional $300 because they had to resurface the drums and replace a planetary set along with some other odd bits and pieces that normally wouldn't have had to be replaced. The trans cooler I had purchased but not yet installed was deemed perfect for it and so they used it along with the new torque converter that was part of the rebuild that also included upgrades for the trans. Was very happy with the work and the trans has been trouble free since other than when I had a band break a few years after. That they took care of for only $500 since it was out of warranty, but not bad for the labor. That all was done about 16 years and an engine ago. Had moved up to 33x12.50's before then, so I figure the rebuild made the trans as strong as the later ones if not better. Might be something to consider, just having the trans rebuilt and upgraded while rebuilding. 

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Thanks for the replies, guys.

 

I am hoping to find an already pulled transmission from a junkyard or shop; Pull-A-Part is definitely my last option as a necessity only. I do not mind spending a little extra to save myself the trouble of repeating the job anymore than I have to, for sure.

 

I'll probably get whatever I buy rebuilt, I just hate to rebuild the one out of my truck since I could drop a little more money to have the newer design with the supposed better internals of the 2001-2004 models. In the end I'm just reviving the old girl to have a fun truck to wheel on the weekends and to be able to take passengers with me when exploring the trails (as opposed to the normal motorcycle route).

 

I'll definitely have a look around the other side of Atlanta to see what I can find, and I appreciate the tips.

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A small update... I have been able to locate a few local prospects that I intend to look at, though, I am not an expert at transmissions (only an expert at worrying myself with second thoughts and doubt) but I'm not sure how to tell if there is a difference between the supercharged frontier/xterra transmission and the non-supercharged version. The thread "RE4R01A-HD Information Thread" or similiarly named, specifies that there is no external difference and several member have posted that they would compare the two versions of the transmissiom side by side. Reading the factory service manuals for the xterra and frontier compared against my 94 Pathfinder factory service manual shows that the supercharged version (and the VQ35DE) should have a second sensor near the bellhousing that the other non-suoercharged version of the transmission should not. It also provides transmission codes for the VG33ER 4x4 transmission, though, I assume someone would have been able to tell that the code doesn't help either, as noone else in other threads I can tell have been able to point out a difference for certain? In either case, the scrap yards I have spoken with specify their transmissions are from a supercharged Xterra or Frontier and I am aware I need the transmission, torque converter, and flex plate. I suppose I am to pick those up in the coming days to get the project started. Does anyine have any other pointers, tips, tricks, hints, or friendly advice on doing the swap that I might have missed?

 

Thanks!

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Okay, next update, mostly as a log for myself I suppose...

 

Yesterday I made the 5 hour round trip to fetch my 'new' transmission. It came with the transfer case, which I did not expect. This is where I am baffled... There is an entire thread, from not that long ago, dedicated to information about the supposed HD version of the transmission released with the VG33ER and VQ35DE engine equipped vehicles of certain years. It is said these are the best bolt in replacements, but there is a lot of confusion about identifying them. The factory service manual listed the transmission model codes for the VG33ER specific transmissions, which my new one matched, the VIN of the donor car had an 'M' as the fourth letter, and it has an extra sensor that my current transmission doesn't. Do I have something wrong, or misplaced guesses at what I am supposed to be looking at?

 

Anyway, my confused babbling over, the transmission came from a Frontier with about 140K miles. The staff were super helpful and friendly (shout out to Turner and Sons Auto Parts in Gillsville, GA), the transmission with transfer case and torque converter was only $300, and they loaded it into the truck bed for me. I didn't even break a sweat, which is saying something for this Georgia heat.

 

I suppose the next step is to get it cleaned up, drain the fluids and flush the cooler lines, then get it in there. I do need to locate a transmission jack because that assembly is more than my stick self can wrestle.

 

If anyone has any tips on flushing the transmission, valve body, torque converter, or cooler/lines, feel free to throw some knowledge my way. If any has any questions or wants any specific photos of the transmission before I install it, I am happy to oblige. Until the next update, thanks to you smart folks for all the good info, and for helping my keep my hands dirty!

 

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That’s a smoking good deal. I don’t know much about the HD version. I do know that folks put some power on these transmissions inside the 240sx, 300zx, and R33 Skyline.

 

More than anything I think it’s important that the transmission was kept cool in whatever vehicle it was in.

 

As far as I know the best way to flush the trans is with the cooling lines. I would go ahead with the install and then change the filter before startup, top off the oil and run it for a while. After you know it’s going to be a good one then flush the oil out the cooling lines and fill it back up with some good quality stuff. I am going to put some synthetic Amsoil stuff in mine later this year.

 

Are you familiar with flushing the trans thru the cooling lines?

 

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Cooling line flushing would be placing the intake line in new fluid at a level lower than the transmission to fight air bubbles, and the discharge line in a waste bucket? I haven't messed with many automatics, so I am just guessing at that. The last time my Pathfinder has it's fluid changed (in 2013 or 2014, right after it began to hang up and not shift from first) I took it to a shop.

Or would I want to fill it through the dipstick as usual, still using the discharge line as the drain?

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Safest thing is to replace seals and gaskets while the trans is out, that "filter" is not really a filter in the conventional sense, it is actually a fine mesh screen that self flushes when the engine is shut off. The fluid flowing back out of the valve body washes it out and lets the debris collect in the pan. It doesn't hurt to replace it when the pan is off though. 

Standard practice of maintenance service on the trans is a periodic drain of the trans to allow worn fluid and debris out, then refill with fresh fluid. I recommend it at 15k mile intervals. Doing that will keep it healthy. With an install of a used trans, if you don't have a shop go through it, drain as much as you can, install trans, fill with fluid and drive for a few hundred miles. Then take it to a shop and have a flush performed. The 2 bucket method is sketchy at best and can lead to issues. Otherwise, do a drain and fill 2 or 3 times with a couple hundred miles between. 

 

My professional opinion here. I do the drain and fill method with my own even though I have the use of flushing machines at work. 

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Oh yeah definitely install the input and output shaft seals before you install the transmission. There is also an o-ring on the input shaft that seals inside the torque converter. I couldn’t find the seal at any auto parts stores but I did find it at Ace Hardware in the faucet o-ring section. Make sure it’s buna-N rubber and not ethylene-propylene(EPDM).

 

It won’t suck the new fluid in. You use the discharge line to empty it and refill thru the dipstick tube. It’s better to have a second person starting and stopping the engine.

 

I use two painter’s mixing buckets so I can see exactly how much oil is discharged but you can use any clean buckets.

 

Take both lines loose at the radiator and put them in the bucket.

 

Have someone start the engine so you can see which lines discharges.

 

Reattach the line that doesn’t discharge.

 

Have someone start the engine again while you hold the discharge line into the bucket. While the engine is running watch as the oil fills the bucket. Bubbles will start to spit out of the line and as soon as they do call out for the engine to be shut down.

 

Measure how much came out and put that exact amount back in thru the dipstick tube. I use two identical buckets and I fill the one with new oil to match the level in the bucket filled by the discharge line.

 

I think about 3 quarts come out at a time before the bubbling starts. You’ll just keep this cycle going until the darker oil is replaced with bright new oil coming from the discharge line.

 

You’ll want to have 12-13 quarts for a full swap.

 

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Alright, good info, thanks guys! I got the truck cleaned up and prepped for surgery today. I hope to get started on pulling parts out a little at a time each day after work. I'll definitely get on swapping those seals/gaskets, changing the 'filter' screen, cleaning the pan, and such.

 

I appreciate the input!

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17 hours ago, onespiritbrain said:

Oh yeah definitely install the input and output shaft seals before you install the transmission. There is also an o-ring on the input shaft that seals inside the torque converter.

 

 

I'm looking at the Nissan parts diagrams for the transmission and I'm pretty sure I the o-ring you are talking about, but I'm a bit confused about the seals... The seals I see for the input and output shafts seem to be buried behind a few snap rings and plates. Surely I am looking missing something? If you have the time to track a part number or lookup code on a diagram, I'd be eternally grateful.

 

If it helps, the truck I got the donor transmission from has the VIN:

1N6MD29YX2C378481

 

I am gonna go and see if I can scour the factory service manual again for a better exploded parts diagram. If that fails, I'll just have to watch one of the RE4R01A tear down videos to see where any seals come out.

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So I think with the help of clearer diagrams from the FSM that maybe I've found the seals and 'filter'. It was a bit confusing with the 'filter' because the parts website shows parts actually labeled as automatic transmission oil filter right above the listing for the oil strainer. I think the oil strainer is the part needed, it most appears the same to all other A/T filters I've seen before.

 

My part numbers, again listed for mostly my own log, but also for anyone in the future possibly hunting this information as I am now:

Filter/Screen: 3172841X03

Input Shaft Oil Seal: 3137551X03

Output Shaft Oil Seal: 31375-41X01

O-Ring on Input Shaft at Torque Converter: 3115921X00

Oil Pan Gasket: 3139741X05

 

I also managed to located and order the flex plate (Nissan calls this a Drive Plate)  needed for the 'HD' version (Part Number: 123315S700) for $60 shipped from a salvage yard in south Alabama. (This was difficult to locate as many yards showed it in stock but had sold it with the engine.) 

 

I again can't state how much I appreciate the help of both those directly commenting in this thread, but from all of those who have provided information on the topic of not just transmission swaps in general, but for all of the stuff we need to keep our wonderful old trucks rocking and rolling!

 

✌️

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Good call on changing those seals. I didn't when I put mine in but didn't have any issues. It's always a gamble though.

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I got the flex plate in yesterday, it seems to be in good shape. While looking to order seals I thought about things and realized that the rear main probably should be done while the transmission is out. With that being the case I think I might go ahead and pull the engine for a rebuild while I'm at it. I am completely lost on what to do now. I think I'll keep the VG30E, grab a bottom end rebuild kit online, get the block looked at and maybe bored over some? I'm not sure if it NEEDS it, and I hate to spend extra, but most kits look like they come with over sized pistons anyway. I'll probably buy some re-manufactured VG33E heads since the local shop here quoted me "$500-600" to rebuild the VG30E heads. I could do the parts replacing side of the head rebuild myself, but I am already looking at biting off a REALLY big bite as it is and don't know how quirky these things might be. I'll replace the radiator, cooling lines, and vacuum lines while it's all apart as well. I'm kind of just scratching my head and debating so much with myself on what to do. I could do a VG33E swap, but I don't want to buy another used engine, I don't think. The JDM engines are nice but only come as long blocks and aren't any cheaper than the rebuild of the VG30E.

 

Anyone have 2 cents they'd like to throw in? I'm honestly on the fence about what to do, and as a complete amateur at all of this, I'm excited as it would be my first real 'solo' engine rebuild. I did plan eventually to pull the engine for a rebuild or...something?, anyway, since it leaks really bad on the bottom end and possibly burns oil. It's been running so rich I've had a hard time telling.

 

Thanks!

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Putting new bearings in the bottom and new rings for the pistons sounds like a good idea to me. You could also go ahead and put a new oil pump in there. Redoing the top sucks butt.. FYI

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I think that my idea for pulling it and doing a full rebuild is what I'll go with. Having a daily driver that gets great gas mileage and some disposable income to throw at her makes me want to really get her going. If no other reason than to show myself that I can do it, and that I shouldn't regret not buying a new Wrangler.

 

I guess I'll eventually start a build thread once I get elbows deep into it and continue things there.

 

In the meantime, thanks to you who have given me advice!

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