We have a Stick shift 4x4 '88 CHevy Suburban, Husband says the Rear end is going, he keeps driving the thing, it sounds like it is about to Break down, sounds normal when foot is on gas, but when off -starts GRINDING terribly, clucking , I am afraid to drive it-but have to sometimes for short trips. He says when it quits, since it is 4x4, he can just take that part off and use it like a front wheel drive. Is this correct??? I don't know if we should look for another vehicle or try to repair this (because of gas prices!). We do have a 78 Blazer & 79 full size Short bed chevy in the back yard we use for parts, would the rear ends from these work on this 88 Suburban, ---where to look to find out if they would, any idea? I have to drive this tomorrow, if it completey breaks on me, what will happen, will something fall on the ground, will the whole vehicle come to a stop? Is this dangerous -in other words? Thanks for all the help :confused:

First off.....I would be concerned with my safety playing russian roulette with a 6,000 lb vehicle and the safety of other that might be in your path. If the rear-end goes what happens depends on how fast you are traveling! If the rear end locks up at 60 mph....then how far will that 6,000 lb missle travel before friction finally gets it stopped....I'm guessing about 400 ft.

Your husband is talking about removing the rear driveshaft and driving with the front drive only...problem is, is that the axles are still turning those rear end gears and the problem will still exist.

Changing the gear set or doing a complete rear end swap are your options. If you wait until the rear end goes completely the insueing melt down will not only destroy the gear set etc., it may destroy the case holding all the hardware, so you would end up having to replace everything, possibly including the axles. Find out what the gear ratio is because the front and rear sets have to match. Either get a set of gears for the rear or completely change out the rear dif with a salvage unit or from one that you know is good and can trust.

Thank you, I will give him this info, I don't think we should drive it either, I guess I am just pushing him to FIx it NOW -because we need 2 vehicles. I hope he can figure it all out, otherwise, I will be on here with a ton of questions during the process. Thank you for your reply.

Please tell me how to go about figuring out what the gear ratios are --to see if they match. Is this stuff engraved on the metal somewhere, is there anyway to look this up on the internet with the (3) Chevy & year trucks we have -if they would be a match?

Usually there is a tag on the rear end attached to one of the cover bolts. also there is a tag in the glove box that has a list of codes that will tell a tech what the ratio is. The rear end is not hard to replace if you are a somewhat competant mechanic...the trick is in the set up of the ring and pinion gear. This has to be set right or major problems will occur. There are a few board members that will probably come on here and be mopre sprcific with ratios and where to find them.

If you're in a bind for a truck, just install one of the rearends out of your parts trucks and don't worry about the gear ratios. Just don't use 4 wheel drive and it won't matter if the front and rear axle ratios are the same.

First of all---Is it the rear end or is it a U-Joint? Second the repairrs should be done MUUUY_PRONTO, or a very exciting time could be had by all.

The vehicles we have in the back yard are both 4x4's also, one is a 78 full size Blazer, the other is a 79 chevy Full sive short bed truck. Does anyone know if swapping these would be a perfect match. Husband has not had time yet to check all of this out.

Husband says it is the Rear end, please give more detail about what kind of exciting time would would have. I refuse anyone to drive it until it is fixed.

If the rear end gear locks up or binds at any speeds above a slow roll, the driver and passengers would have the equivalent experience of a roller coaster ride going off of it's tracks. The vehicle could go into a roll or worse cause someone else to either rear end your vehicle or you end up hitting them while trying to stop the train wreck. I personally would not drive this until fixed. Do not drive with the front axle pulling only, this will not stop the rear end from disintigrating, since the axles are turning inside. If it was the U-joint, then he could take the driveline off and the front axle would suffice for driving.

As for a change out of the rear ends, the complete swap of both axles from a donor would ensure that the axles were the same ratio, however as stated above, if what you need is transportation and the 4X4 was not a necessary need RIGHT NOW, then I would change the rear axle only and then look into fixing the other axle or doing the rest of the swap later. Some rear ends have a different length on the housing where the input shaft is, so your driveline may not fit the same as it did with the old rear end. Something that can be fixed at a driveline shop. The U-joints may not be the same size either, also fixed at a driveline shop. The axles should unbolt from one vehicle and bolt onto the other, I believe, without any problems consider the length, axle pads, and brake lines. Are the rear axles of the same bolt design (10 bolt or 12 bolt)? That is the number of bolts around the housing cover at the rear of the axle.

The noise in your rear end could be the spider gears (a cluster of gears inside the carrier assembly that the axles fit into inside the axle housing) demonstrating a large amount of wear. I have had to replace the spiders before and GM (as well as many parts outlets---Napa, Carquest, etc) has a replacement package for those. It is a simple job and it only takes a couple hours with the rear axle still on the vehicle. Have a qualified mechanic look at your rear end and then make your decision from there. It might be more simple than first thought.

If nothing else---don't drive it to failure---you will be sorry in the long run.....

Husband said it is not the U-joint and none of the rear ends in our back yard will work. Doesn't the kit to do this job cost like $900 , that is what he said, if we take it to the shop, I can't imagine what the price tag will be. This 88 suburban has 10 bolts and everything older in our back yard has 12 bolts I guess. Never heard of a driveline shop, you must mean a Garage that fixes things or a particular mechanical garage?

Doesn't matter if it is 10 or 12bolt. All you need to do for the swap is get the hybrid u-joint. A 12 will bolt into the same spot a 10 came from. You need to fix it and stop driving it before it gets worse.

OK---I am getting the feeling here that you and the husband are out on a limb here. Your husband stands by the fact that the U-joint is not bad--Good Deal---The noise is definitely coming from inside the rear end, so now we have to decide what to do. As I stated above, the problem could be the spider gears, they are an assembly of four little gears that are inside the carrier assembly that the ring gear mounts on (inside the rear end). The last time I had to replace these, I had about $200.00 in parts involved --- No idea what the price is in your part of the country. The complete carrier assembly for a truck is not even $900.00----I bought a brand new posi unit for my son's truck for $450.00. I am looking at the LMC Truck catalog ( www.LMCtruck.com ) and the List price for the spider kit is $149.00.

The axles in your older trucks WILL bolt up to the Suburban leaf springs, unless this Suburban is the late model style (like a an 88-98 Chevy pickup. However, you have to think about all of the items that need to be done to do this work. The U-bolts will be hard to get loose (rust and road dirt), the emergency brake cables need to disconnected and re-installed on the Burb, the brake lines will have to be disconnected and reconnected--with a brake bleed done afterwards, the shocks will have to be disconnected and reconnected. The U-Joint yoke may not be the same on the input shaft as your present setup, so it will need to be worked out. I have installed two 12 bolt axles on trucks that had 10 bolt axles and there is a slight (ever so slight) difference in the length of the center housing and you may have to have the driveline reworked---or MAYBE not you never know until you are done.

A drive line shop is a place that specializes in repairing or builiding drive shafts and balancing them for cars, trucks and heavy equipment. I live in Kansas and there are numerous ones around where I live, so they are a common shop in most repair communities. A good mechanic can tell you if there is one close by. I also take it by your input that you are inclined to NOT go to a shop, due to cost, so I would ask around some to find out what is available in your area and what you would be getting into with this project.

Thank you so much for your help. I did call a shop and it would cost at least $1,000 or more, and if something something was bad, they made it sound like they just get a rear end from Junk yard & give you a 30 day guarentee on it (I did not like the sound of that at all) , otherwise, this guy quoted something like $4,000 to replace. My Husband wants to do EVERYTHING himself and he manages somehow, we have NEVER taken our vehicles anywhere to a shop -except for Transmission rebuild once. But this is something he has never tackled before, trying to gather the right information. He seems to know what all is involved-even though he has never done it -the swapping that is, he was also saying before I got your reply that the 10-12 bolt may still work, that he had to check something else. He just told me that the Universals are not the same size, so I guess we can scrap our vehicles in the back yard for this job. The replacing-redoing the spider gears-- that would make him very nervous I think. Any good links on the net to explain what all is invloved if we open this thing up and reguild ourselves, and why would the car shop not do this option, very confused. I called a place that is one of the most recommended in the area.

What is a Hybrid U joint ? Would this solve the swapping problem?

I just asked him whaT HE thinks the problem is and his answer was... the bearings for the pinion gear --because of the grinding noise. He figures if the gears were bad, it would be doing more than grinding. ??? What do all of you professionals think?

A hybrid u-joint is one that is 2 different sizes. I think it is number 1328. Most all autoparts stores have these, I believe Napa PN is PUJ372 The donor trucks are the simplest/cheapest solution to your problem.

Here is a link to it:
http://www.napaautoparts.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=PUJ&PartNumber=372&Description=Univeral+Joint+(U-Joint)+-+Combination+-+Universal

Man; I am glad that I don't live back East. Your car repair shops are taking you to the cleaners. I had a complete rebuild on an axle done a few years ago and that included a new ring gear and pinion shaft for $800.00, here in Kansas. I even bought a rear axle out of a 3/4 tin truck, with a posi unit in it for $600 dollars. I still think that you can bolt in the axles from the older trucks, but the gear ratio issue will possibly cause the changeout of both the front and rear axles. The U-Joint and yoke problems will take some replacement parts. Some setups have a U-joint of two different lengths on the cross pieces. I personally don't like these. A new yoke can be purchased or the one off of your old axle's input shaft might be used for the replacement 12 bolt ---that will take some investigation to find out. Surely the price mongers in your area would let you buy one of these without taking one of the children (Sometimes we would be better off if they did take one). If you happen to have air tools and an acetylene torch to help take the rusty bolts off, the job can be done in a fairly short period of time.

I have a complete 10 bolt rear end (brake drums with good brake shoes, and all) out of my son's 86 Chevy 1/2 ton pickup sitting behind my garage. I can't even find a buyer for it. It is a 3.08 gear ratio and most people want something different for their trucks, sorry that I am to far away to help you.

Check this out......

Some Jobs are Better Left to the Pros
By: Jim McGowan


In early September 1964, a southern Californian who loved the styling of the new 1965 GTO checked all the right boxes on the dealer order form except one: the rear gearing. This musclecar was delivered with a 3.23:1 non-positraction rear end, and it stayed that way until a recent horsepower upgrade and transmission rebuild demanded more low-end performance. The decision was made to yank the one-legger and install 3.55:1 gears and a posi.





Many suppliers carry the parts to accomplish a rear end gear change. Complete installation instructions are usually included with these kits, but a word of caution is required: This is not a job for a novice auto enthusiast. If you are not experienced in working on rear ends, then this gear change is best left to a professional. The most difficult part is setting the pinion depth with the correct shims and installing the correct amount of shims on the carrier. If it is not done properly, the gear meshing will not be correct and the rear will howl while going down the road. It's time-consuming and sometimes frustrating, but it must be done correctly. Also, we manufactured our own tools to press on the carrier bearings and the pinion bearing from a piece of steel pipe (1 7/8-inch OD, 1 1/2-inch ID).





While the average weekend hobbyist should probably have a pro do the changeover, this overview shows what it takes and how much work it really involves. The numerical difference between 3.23 and 3.55 is not that great, but the low-end performance and torque are very noticeable and make all the effort worthwhile. We are working on a 1964 GM 10-bolt, an axle that basically remained the same through 1972. We used normal shop tools for the R&R, but a few specialty tools like a dial indicator and bearing puller make certain parts of the procedure go a lot smoother.






Axles

Obviously, we have removed the rear wheels and brake drums. Before removing the four nuts securing the axle to the rear-end housing, we cleaned the entire brake area to remove debris and accumulated brake dust. The nuts securing the axles are accessed through holes in the hub by simply turning the hub until you can get a ratchet on each nut and remove it. Then pull the axles out of the tubes. The axles might require a little coaxing, but will come free fairly easily. While the axles are out, it's a good idea to have new axle bearings installed so you don't have to worry about them in the future.



Carrier

Two caps and four bolts secure the carrier. Mark each cap with top and left or right�these must be replaced in the same position as you removed them. With the caps removed, the carrier is now pulled forward and the shims removed from one side at a time. These shims may be reused, so mark which side you removed each shim from and set them safely aside. The carrier can now be rolled forward and removed. This item is heavier than it looks, so having a spare set of hands will be helpful. Make sure that the install kit you use has new bearings, bearing races and a selection of shims for the carrier and pinion gear.



Pinion Gear

In order to remove the pinion gear, the driveshaft yoke must be removed. A large nut secures it to the pinion shaft, and this nut must be removed with either an air tool or breaker bar. It is seriously tight on the pinion. After removing the driveshaft yoke and front pinion bearing, we tapped the pinion out and removed it from the case. This gear, along with the 3.23 carrier, will be put on the shelf and kept with the car. Have an extra set of hands at the rear of the case to grab the pinion gear as it comes free.



New Races

The new pinion-bearing races must fit flush with the surface of the case. We tapped the race in slowly until it was in the exact position as the original. This is a project that is not accomplished quickly, so have patience. New races should be installed in both the front and rear of the case. A short piece of 2x4-inch wood and a hammer is the at-home installation method; a professional shop has a special tool called a "race driver" to accomplish this task. Some specialty tools are required to save time and make for a better install.



Ring Gear

Before installing the ring gear, carefully clean the mating surfaces of both the ring gear and carrier. This must be a perfect mating surface, so it must be squeaky clean. The ring gear is now secured to the positraction carrier. Once the bolts are finger-tight, a torque wrench is used to tighten them to spec (50 lb.-ft. in this case), using a crisscross tightening pattern. After all bolts are tight, double-check their torque to be sure. The axle splines slide into each end of the carrier. The driveshaft turns the yoke and pinion; the pinion meshes with and turns the ring gear, which in turn spins the axles through the carrier.



Backlash

A dial indicator is now used to check the backlash. The pinion must be fixed so it can't turn, and the dial needle measures the free play (backlash) between the ring gear teeth and the pinion teeth. Ours was ideal at .008-inch. If you want to increase the backlash, you must move the ring gear away from the pinion and visa versa. The instructions will give the ideal setting for your rear end. Spacing is accomplished using shims of varying thickness. It took us several attempts to get it right. We used a micrometer to measure and mark the shims to make selection easier.



Tooth Contact

Here we see an ideal contact pattern. Moving the pinion closer to the ring gear will move the pattern deeper on the tooth (flank contact) and slightly toward the toe. Shimming the pinion away from the ring gear will move the pattern toward the top of the tooth (face) and toward the heel. Gear-marking compound should be included with your installation kit. Brush the compound on several of the ring-gear teeth, then rotate those teeth back and forth through the pinion gear teeth to establish a contact pattern. This procedure must be repeated after each shim installation to guarantee the correct tooth contact.



Precision Check

Since this is such a critical procedure, make sure you use only the best parts available. Using a lift or removing the rear end from the vehicle is practically a necessity, taking into account all of the checks and rechecks required to get the contact pattern precise. This exercise took three of us almost eight hours to accomplish; most of that time is fitting and shimming to perfection. If we had all the correct professional tools and considerably more experience, we probably could have cut the time considerably. That's another reason to have a pro do the install.



Final Steps

The case cover was bead-blasted and painted, and the rest of the rear end cosmetic resto will follow. A new posi tag added the final touch. We used GM 90-weight gear oil and positraction additive, which is available at most GM parts departments. Fill until the fluid leaks out the filler hole in the side of the case (about 2.5 quarts here). Brush a light skin of gasket sealant on both sides of the gasket, then torque the bolts about the same as you would a valve cover bolt and you're done. The gear manufacturer recommended three 15-minute cruises, with a cool-down period in between, to set the gears and break them in. After that, it's driving as usual.

Wow, that was ALOT of information. We are taking your advice and getting a Pro, I called a local respected Auto Parts store & asked if they knew anyone in the area who works on Rear ends and he recommended someone immediately--That is all this man does. I called, he does rebuild them, he does not swap junk yard rear ends& his prices seemed awfully reasonable to me. I asked the most it could cost and he gave me an example of about $300 if not too much damage, if alot -- around $600. I was just hoping to keep it below $1,500 if we took it somewhere, so even if it was double his high quote, we would be pleased. Attempting to "slowly" drive it to his house tomorrow. Thank you all. A load off my mind. Yesterday the computer crashed, so got that to deal with now.

Call the geek squad.....