locating rear differential parts - impossible?

[Bala]

Since I've had my van (2 years) it came with a "whirring" sound coming from the back when the gas pedal was engaged. When my foot comes of the gas it goes away. Over 30 mph is when it's more noticeable. It almost sounds like a fan motor. The sound is not too displeasing, just brings me concern.

I had a reputable mechanic take a ride and he said it sounds like my pinion and ring gear are worn. When rocking the rear tires from front to back there is some movement of the vehicle. So my question is, if this sounds like a worn pinion and ring gear, what in the hell are my options? I've checked all over the place for a new pinion set and come up empty. Four Seasons Auto in Vancouver, Wa could order one from Japan for around $800:yikes:

It might be a good idea for me to start a thread on the parts that are impossible to find so that van owners don't have to waist there valuable time looking for parts that don't exist. Since 4WD vans don't show up in the U-pull very often (just because they are rare) and pulling a pinion and ring gear consists of sliding the axles out, it seems like I'm screwed on this one.

Is my only option to either bleed $800 or just drive until the rear differential goes out to then have 4WD activated always for a front wheel drive vehicle? :wall:

[timsrv]

I'm assuming you have checked the gear oil in the differential.......right? If not, you might want to do that ASAP. Better yet, drain the old (assuming there's some to drain :doh:) and change it. I like the synthetic royal purple stuff that Napa has.

Okay, so you've done all this and it still whines..........if it isn't bothering you too much, then I'd let it go for a while. If it gets worse fast, then failure is probably near. On the other hand, I've had rigs with whining differentials that lasted forever without getting any worse. The good news is that even if it fails, unless it seizes up (unlikely), you will not be stranded. You will still be able to engage the 4wd and drive home with your front drive-train.

Although rare, these 4wd's still show up in the pick-n-pulls. On average I still see about 2 or 3 per year......so stop by every couple of weeks and keep your eyes open. I'm not sure what they will charge you, but I picked up a complete front differential for my All-Trac Previa from the Pick-n-Pull in Sherwood earlier this year........the cost was a mere $50!

One thing to keep in mind is gear ratios. The good news is that all 4wd vans 87 - 89 have the same ratios (as long as you stick with the same type transmissions). Do not try to intermix differentials between manual transmission to automatic transmission vans, or you will have trouble (autos and manuals have different ratios). If by chance you have a manual transmission van, you may wish to replace both differentials with those from an automatic van. Since automatic vans have lower gear ratios this will allow you to run bigger tires without sacrificing your low end performance while off-road :thmbup:. Tim

PS: If you end up going for a Pick-n-Pull differential, I'd leave assembled and take the entire axle housing fully loaded, then swap it out without opening it up (don't forget to add gear oil as they are required by law to drain them before putting in the yard).

[Harbilly]

And if you trust them not to forget some pick and pulls will put you on a contact list for when, and if, what your looking for actually shows up. Just don't give them too much info or tell them your 'desperate'.

[timsrv]

And if you trust them not to forget some pick and pulls will put you on a contact list for when, and if, what your looking for actually shows up. Just don't give them too much info or tell them your 'desperate'.

Hey Harbilly, welcome aboard! Glad you found us!

Notifying people on waiting lists must be one of those friendly Canadian things. I've actually asked to be notified at a couple of our Pick-n-Pulls but all I got was a chuckle and a "we don't do that" sort of remark. Often times the guys working the counter don't even know what's in the yard. I've been told they don't have the type of vehicle I was looking for, but then went in and found one.........In addition I've also been told they have something only to find out they actually don't.

It's also been my experience that it's a pain calling them (half the time they don't answer their phones), so I make it a point to stop by whenever possible, pay my $2, and walk the yard. For you local guys, I'll post a thread in the "Parts for sale" (http://www.toyotavantech.com/forum/forumdisplay.php?13-For-Sale-Parts-amp-Accessories) section every time I find a recent addition (van or Previa) to the pick-n-pulls in our area (Vancouver WA, Portland Or, Sherwood Or, and Damascus Or). When possible I'll get a picture and list details about what it is and how bad it's been picked over. Don't rely on me alone though, because sometimes when I'm busy I can go months without a salvage yard visit........and the ones in Oregon can be even more scarce (especially Damascus). Tim

[Harbilly]

Thanks Tim I'm glad to be here. One of our pick and pull chains also lists all new incoming vehicles on line too which can be a help. I never thought about all of us pulling together and posting what we see in the yards. If lots of us do that we may have to think about how to manage it. Forum sections, North West, Mid West, Western Canada or something. But there probably won't be enough interest though, frankly, the amount of good parts out there is drying up. Something under my 89 4WD goes thump when I change gears and I know it isn't the clutch so I'm thinking 'oh no, my U-Joints are staked' and there isn't a 4WD in the local bone yard so I may have to follow the advice in your article rather than just buy a u-joint in a box.
Sigh.

[slosurfer]

As far as I know, these have the same rear 7.5" differential as the the 2wd toyota trucks, so gears, parts, and whole diffs should be easy to come by. The reason you're having trouble is because you are looking for van specific when you don't need to.

[slosurfer]

just google " 7.5" toyota ring and pinion " and you should have plenty of aftermarket gears available. :thmbup: While you're in there, you could even throw in an aussie locker, arb locker, or a limited slip.

Just make sure that you don't get the 7.5" REVERSE CUT ring and pinion as they are for the '96+ IFS fronts

Here's a set
http://www.ringpinion.com/ProductDetails.aspx?ProdID=1110

[Bala]

just google " 7.5" toyota ring and pinion " and you should have plenty of aftermarket gears available. :thmbup: While you're in there, you could even throw in an aussie locker, arb locker, or a limited slip.

Just make sure that you don't get the 7.5" REVERSE CUT ring and pinion as they are for the '96+ IFS fronts

Here's a set
http://www.ringpinion.com/ProductDetails.aspx?ProdID=1110

Wow...is it really that easy? It sounds too good to be true.:yikes: What year 2WD Toyota trucks would qualify for matching differential parts? Are the diffs really identical?:cnfsd:

[slosurfer]

I don't know for sure, what years, but your best bet are probably 80's up until the 95ish when the tacomas came into play. I'm found a cool pdf with a chart for decoding the diff size and gear ratio, but I have to figure out how to upload it.

Toyota is usually really good about keeping stuff similar between different makes and models. For example the 89-95 4wd IFS uses the same 7.5" ring and pinion and internals as the 7.5" for some of the 2wd trucks. Also, the same internals from some 7.5" supra diffs can be swapped as well. I know lots of people with supra limited slip lockers in the front of their 86-95 4wd IFS and it should swap into the rear of our vans as well.

The aussie locker that I have in the front of my 93 4runner (7.5" IFS), can also be used in the rear of our vans. :)

[Sean]

The parts inside the differential are all fairly standard Toyota 7.5" parts, pinion...bearings all that stuff is the same as the trucks.

The 3rd member may be somewhat different, if I remember correctly, (that's the part that holds the differential in the rear axle). There's a few different types on the trucks.

I installed a limited slip differential in my van a couple of years ago, and didn't quite have everything I really needed to set it up correctly and toasted the bearings within about 500 miles (I couldn't adjust the pinion pre load). Plus I failed to understand proper break in proceedures and living at the top of a 2500 ft grade may have hastened the demise of the bearings that were brand new and took weeks to get.

The second time around I decided to just ship the 3rd member off to a 4wd differential specialist in sacramento and have them install a new ring and pinion along with bearings and setup. I figured they would have the bearings, ring, pinion in stock where my dealership would spend alot of time waiting on parts. The cost was reasonable for the work performed (I had done it and failed, and knew what labor was required) and the brown truck delivered my rebuilt 3rd member to my door in 2 weeks. I don't think my local dealership would have had it back to me in nearly that time. Sometimes it's best to go with the true specialists. This time I was super carefull during break in, changing the fluid 3 or 4 times in the first 2500 miles. I finally settled on the Redline shock proof gear oil... Not cheap, but you don't change that oil too often, and I probably put 1200+ into rebuilding my rear drive train so it's cheap insurance.

That said I think I've been in places where I would have been stuck without the LSD. If you really need a 4wd but have a 2wd van it's the best option, but carries a pretty hefty price tag.

Your best low cost bet would be find a doner 3rd member from a lower milage van at a junk yard, bring the slide hammer puller like toyota reccomends for removing the axels... one of my axels slid right out the other one wasn't moving for nuttin without the slide puller. It just makes the job quick and easy. The 3rd member is heavy 60+lbs.... be prepared if you pull it.

Sean

[timsrv]

Thanks guys. This is an area that I'm pretty weak in. At some point I'll probably take both the differentials out of one of my automatic parts vans and send them off for some mods, then install them in my 5 speed 4wd when I put the big tires on it.

Sean, do you happen to remember the name of that place in Sacramento? I seem to recall being told you couldn't get electric lockers for 7.5".......is that true? If I can't get electric, what's the next best thing available? Keep in mind I want to be able to drive this on the road without squealing tires when I go around corners :)>:. Tim

[Sean]

I dug out the info for you guys who are looking at doing something like this:

there's many different Limited Slip Differentials out there... many use clutch plates that you have to add special additives to your oil for these to work properly, not to mention drive figure 8's for half an hour to wear them in before getting on the road. I really liked the design of the detroit trutrac worm gear LSD. No plates to wear out, no special oil. If you search around some people have had some issues with them, but that will happen with anything mechanical. For our vans the one of these your looking for is model number: 911A565 ... there's another 7.5 Toyota LSD but it's designed for the front differential and has a different preload setting and to work in the rear you may have to flip the worm gears. It cost 537 shipped from justdifferentials.com (http://www.justdifferentials.com/index.php?main_page=index&cPath=24_51_304). It's pretty noise free, occasionally going from a stop I'll hear a click when it engages but it's not that loud that's all. To get to the parking area at work I've got to pull a tight 270 degree uphill turn on dirt and if i'm heavy on the gas then I'll break my inside tire free that's about the only time. I've got alot of wrench time on my van so I tend to drive it nicely. The LSD does help with traction but you also have to be more careful with your throttle on slick surfaces because you can break those wheels free more easily then with the open differential.

The place I got to service it is West Coast Differentials (differentials.com (http://www.differentials.com)) I think they were having a sale on stuff at the time. The ring and pinion set (4.11 gears... I think automatics may be different) was $200, Timkin bearing kit was $175 and Labor to install everything was $220. I don't know if it would be cost effective to ship the 3rd member far.... I guess it might be offset by no sales tax, but there's some shimming that has to occur for correct alignment of all parts and it could get frustrating for the do it yourselfer figuring out just what shim you need and waiting for toyota to ship it.

FYI - My initial plan was for a powertrax locker in the rear. The cheap solution so I might not have to chain up every time I went to town in the winter... I got one that was out of round and wouldn't install.... Powertrax said it was within their specs and wouldn't make it right. Now I've got a really expensive paperweight. You may not have this experience with it but I did.

Here's a very informative site on Toyota Truck Differentials and differences therein... I don't think the van's on there but haven't read it in awhile http://home.4x4wire.com/erik/diffs/

Sean

[slosurfer]

Tim there are no electric lockers available for the 7.5, but there is an ARB air locker which is similar in the fact that you can turn it on and off. You do need some type of on board air though as it uses compressed air to hold it locked. ARB also sells little compressors just for this or you can run your own system. They are a good strong locker and popular among the 4wd crowd. I'll get the actual part number tomorrow.

The link above is a good one, but unfortunately only covers diffs for the 4wd crowd, and therefore only says that the 86-95 ifs diff has the same internals as the 7.5 rear. (and that the 96+ 7.5 is different in that it uses reverse cut gears.

[timsrv]

Electric would be easier to set-up, but air isn't too bad (just cost a bit more $$$ for the compressor, valves, and other components). I've already installed a 12v compressed air system in my cargo van and it works very well. I put in a Max Billet 30A 12V compressor with a 100% duty cycle and that thing is awesome. I've run it for thousands of hrs now over the past 10 years without any issues. Tim

[slosurfer]

Yeah, the ARB's are tried and true and very good. Sounds like your compressor will work just fine. If I remember correctly, if everything is set up correctly and sealed correctly, the compressor should just kick on every once in awhile if it is locked. The only bad thing about ARB is, you lose your air it becomes unlocked and a regular open diff.

The electric ones are cool because it just switches it from unlocked to locked and back. Power isn't needed to hold it in either position. IN fact, if your locker motor goes out, then you can actually remove the motor and manually switch it from locked to unlock if needed (or the other way around) :)

The ARB part# is RD90 that should work in our vans.
http://eastcoastgearsupply.com/i-131642-toyota-7-5-ifs-arb-air-locker-rd90.html

[timsrv]

Hey that's awesome! Thanks for the link. For $800 a piece + the cost of having a specialty shop install the guts, it will have to wait a while. I do plan on getting to that eventually though. This will be a fun project. Tim

[slosurfer]

Here's a good guide for deciphering the axle codes and gear ratios for toyotas by using the codes on your door sticker.

[Bala]

Here's a good guide for deciphering the axle codes and gear ratios for toyotas by using the codes on your door sticker.

Toyota Axle and Gear Guide (http://www.toyotavantech.com/techdoc...Axle_Codes.pdf)

The link doesn't seem to be working...for me anyway.

[slosurfer]

The link doesn't seem to be working...for me anyway.

Ooops! Try it now, I think I fixed it. :thmbup:

[The hermit]

Wow great thread.tim thanks for the info on swapping the auto gear ratios when running 15s. Also thanks cris foraddressing LSDs ive heard they slip too much to be useful.also that auto lockers lock up at inopportune moments so im leaning towards the ARB (995 per axle ouch). Has amyone actually installed one?

[Ian R.]

I don't know for sure, what years, but your best bet are probably 80's up until the 95ish when the tacomas came into play. I'm found a cool pdf with a chart for decoding the diff size and gear ratio, but I have to figure out how to upload it.

Toyota is usually really good about keeping stuff similar between different makes and models. For example the 89-95 4wd IFS uses the same 7.5" ring and pinion and internals as the 7.5" for some of the 2wd trucks. Also, the same internals from some 7.5" supra diffs can be swapped as well. I know lots of people with supra limited slip lockers in the front of their 86-95 4wd IFS and it should swap into the rear of our vans as well.

The aussie locker that I have in the front of my 93 4runner (7.5" IFS), can also be used in the rear of our vans. :)



Hello, I have a question regarding the Aussie locker. If installed properly in the rear diff, do they make a loud clicking noise when making sharp turns in asphalt?

[Flecker]

Hello, I have a question regarding the Aussie locker. If installed properly in the rear diff, do they make a loud clicking noise when making sharp turns in asphalt?

Yes. Theres a reason they are called "ratchet" lockers or lunchbox lockers... they are mechanical/ spring driven gears.

A limited slip won't make any noise, and traction is pretty fair.