Suspension thread

[Irving]

Everything is worn out on this vehicle. Since I'm replacing things, I decided I might as well lift it a bit at the same time.

[Erni]

Right Stuff is the bomb. Its the only rtv like substance my dad uses in his marine business. Its the only thing that survives in a sea water enviromet too.

[Martinjmpr]

Copy that. I've heard people not want to use synthetic in diffs with LSD out of fear that it'll be "too slippery" for the clutches. Anyone have an opinion on that?

IIRC most manufacturers of LSDs have specifications of what type of lube to run. Also some LSDs require a "friction modifier" in the diff (I think my 1990 Montero did and I had an Auburn LSD in my '99 Ranger that did as well.) I would go with whatever the manufacturer recommended, if that's dinosaur juice (vs. synthetic) then run that.

I know Isuzu had some relationship with GM in the US so I'm wondering if your LSD might be the same as the G80 differential on many GM vehicles (including my '04 Suburban?) If so there should be lots of "institutional knowledge" available on what lube would work best.

[Irving]

It is a G80 differential, but I think there are things unique to Isuzu (maybe). I'm on an Isuzu board that is pretty helpful and one of the knowledgeable guys says pretty much any 90 weight gear oil will be fine. The manual doesn't say anything, of course, and manufacturer only specifies the weight and the additive. I had dino oil with the modifier, then took it back and bought full synthetic with the modifier instead. This truck can use all the help it can get with gas mileage and I figure I'm not a poor high school kid anymore so I can spend a bit more for quality parts.

[Irving]

I use either a gasket, or RTV. ran into problems using both. Learned the hard way doing a water pump on a Camry. Had to do the whole timing belt and WP again because it leaked. Never had issues since. The absolute best RTV is Permatex "Right Stuff". You can get it at NAPA.

The diff hasn't leaked, and I pulled a piece of gasket material off the side of the diff last night when I was checking everything out. I think I'll go ahead and use the gasket since I already bought it, and just be prepared to do it over again if that doesn't work out.

[fportmen45]

Nothing like the smell of burnt gear oil.

Gear oil, Taco Bell, and body odor all smell the same.

[Irving]

Here is a group photo of the parts.


Got the rear diff fluid and gasket changed. Not really any surprises and the old oil looked a lot better than I expected; certainly cleaner than any motor oil I've ever changed. I started to get into the rear shocks and springs, but I can only alpha-male with tiny wrenches for so long before I need a break. Besides that, the shocks came with two different part numbers, but no indication which were front and which are for the rear. I've sent an email to Indy4x and will pick up again tomorrow. Hopefully, I can have the rear finished up by Saturday at the latest. Currently, the shock body turns when I try to turn the top bolt, so I have to mansplain to the shock tower that it needs to hold still (with a pair of pliers), making this very slow going.

Here is a short walk through for changing the diff fluid.

Here is the rear-end. The right side is jacked up in the photo, but you can hardly tell because the axle is still on the ground.


That thing in the middle, sometimes referred to as a "pumpkin" is the rear differential. Here is a close up:


In my case, the bolts are different lengths so it's important to keep them in the same hole. Before I started, I traced the holes in the gasket and slit the holes with a knife so I could push the bolt into the corresponding place as I removed them.


While I was at it, I made-up a star pattern for retightening the bolts. There are 10, so it's basically two star patterns, slightly off-set.


Start by removing all the lower bolts, and only loosen the top two or three bolts. Next you'll gently put a flat blade screw driver in the gap and gently pry the cover loose. The cover will separate and drain all the fluid, and the top bolts that were only loosened will hold the cover for you. There isn't much fluid, so once you start draining, you can move straight to removing the top bolts and most of the fluid will have drained by that time. Then you're looking at this: TIP: Try to brush/scrape off as much crud around the top of the differential as you can before removing the cover, this prevents that same crud from falling right onto your gears.


Next, spray out the differential with carb cleaner to flush heavy build up out. You'll also want to scrape off the remainder of the old gasket/sealant around the edge on both the cover and the diff housing. Be careful not to gouge the metal, as that will increase your chances of a leak if the surfaces are not smooth. In my case, the diff housing is steel, but the cover is aluminum so I had to take extra care not to gouge the cover. Once you're done removing the old gasket, I'd spray out the housing again. Here is a picture after spraying out housing, but before removing the gasket material.



The last step is to replace the gasket (if you're using one) and fill the differential. If using a gasket, run a small bead of RTV sealant all the way around the cover. When you get to the bolt holes, you'll want to run the sealant INSIDE the bolt holes. Place your gasket on the cover and press everything down and make sure the holes line up properly. Carefully place the cover back in place and tighten down the bolts. You'll want to wait the specified amount of time for the sealant to set-up before you fill the diff with oil, check the sealant for instructions.

In the case of this differential, the plug acts as the drain plug, fluid level check plug, and fill plug. The easiest way to fill is to get a length of tube that fits inside the fill hole and over the nipple of the fluid container. My diff only require 1.9 quarts, so I needed two bottles. With the first bottle, I put the tube into the diff, the nipple into the tube, then held the bottle above the diff to drain the fluid inside. I punch a hole in the bottom of the bottle to help flow. DON'T punch a hole in your last bottle! When you get to the last bottle, you pour fluid in, until the level of fluid inside is level with the bottom of the fill hole. Basically, you fill the diff up until extra fluid starts to drip out. A flashlight is helpful here as you can look into the fill hole to see if the fluid level is correct, as you'll be spilling fluid every where by this time anyway.

[Irving]

A little history, the last few times I've started the Amigo, I thought I hear an exhaust leak. While I was laying on my back messing with the shocks, I noticed that it looked like the exhaust was a bit kinked. I started looking around a bit and found that indeed, there is an exhaust leak. Looks like that will have to go as well. I'm not sure, but it looks like I may have backed the exhaust into something at some point and it kinked and snapped this bolt.

[Irving]

Not including drive time, I'm only working about two hours a day, or less, right now. Lots of things are getting done around my place.

[Irving]

Kind of, but let's not clutter up the suspension thread.