88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

[Ed HD]

I can see it now! lol

 

[88gmctruck]

The combination of the tune and the 0411 has really helped the truck out. With the camper I was getting 6.5-7.5 MPG..... This past weekend I ended up getting 9.3 MPG. I about fell over. Mind you this is up a summit and two passes, then back. All at 60-70 MPH.

Did I mention that I can do all 3 of those in overdrive now?!

I was grinning from ear to ear this weekend because of it.

 

[Ed HD]

That's like when I got a tune on my G8. Went from being quick and having pickup, to being an absolute blast. It's amazing how these vehicles are neutered from the factory...

 

[88gmctruck]

That's like when I got a tune on my G8. Went from being quick and having pickup, to being an absolute blast. It's amazing how these vehicles are neutered from the factory...

It really is. I can't believe the difference a tune makes.

---------------

My work is never done......

So, I've been chasing down a rough idle in this truck since I bought it. Not quite a miss but it isn't as smooth at idle as it could (should in my opinion) be. I've had a oil leak at the pan for awhile, and it recently started dripping so I decided to replace it and the timing chain while I was in there.

Out goes a few things.

Once you get here, you have to drop the front diff. Let's just let it be known that a few curse words were said during it's removal and re-install.

Once it's gone you can have a peek inside.

The timing set.

Here is where the second cursing during this project came about. I ordered the GM Performance Parts 502 timing set - the same one I used on the 88, as it's designed for the aluminum timing cover in a gen 6 block. Well, it doesn't work out so well. The Vortec truck has a reluctor ring that fits over the crank gear, which causes it to be thinner. I knew this, but didn't take into account. So a bit of research and I picked up a Cloyes timing set locally for 2x the cost of the GMPP version. To make things worse, Cloyes makes the GMPP version and the only thing different is the thickness of the crank gear.

In order, Stock, GMPP 502 set, Cloyes Vortec 454 Set. The ear pictures show the difference in thicknesses.

Got all that back together, but while I had the radiator out I cleaned it. You'd be surprised how much junk gets stuck in these. Once it was back in I flushed and re-filled with coolant.

Since I was in the mode of chasing the rough idle and giving it a tune-up, I decided to eliminate the plastic shafted distributor with a drop in MSD unit. Not only is it pretty, it is all billet and has a much higher quality cap than the OE stuff.

So, once it was all together I got the timing set within .8 degrees of 0 (tolerance is +/- 2 degrees), did a CASE relearn and still have a rough idle. Not sure where else to look at this point, I've gone through 95% of this thing.......

 

[88gmctruck]

Now, switching away from maintenance, I got around to building a cold air intake. And when I say cold air intake, I mean an actual box that is insulated and sealed from the engine bay...

Started out with cardboard for a template.......

Then I cut and riveted everything together using aluminum plate and angle. The first stages...

And here is the finished product.

The outside is covered in DEI floor and tunnel shield, rated to 1750 F to insulate the box. I decided I wanted a smooth lid so the inside is insulated on it. It's held on with stainless torx screws from a GM squarebody.

It's a bit of a squeeze, but I managed to get an OEM sized filter in it, plus i'm still able to disconnect and remove the battery with no issues.

To create a seal and flex joint, I used some sheet rubber and made a retaining ring that holds everything together where the pipe passes through.

That is all, for now. I plan to clean up the lid some more (brushed or polished, haven't decided) and do a few other things to it, but I'm happy with how it turned out. I'm not really expecting or hoping for any gains, other than the fact that my non-intercooled supercharger will no longer be pulling in hot engine bay air (you know that exhaust manifold is really close to it all).

 

[ak diesel driver]

just curious as to the jog on the fender side? doesn't appear to be anything there

 

[88gmctruck]

just curious as to the jog on the fender side? doesn't appear to be anything there

Space for the hood hinge to close.

 

[Will L.]

Ahh...
I was wondering same thing. Sorry, your just gonna have to take out the hood hinges and make it a lift off like the 70's drag cars just for your air cleaner.

 

[DieselSlug]

Looks good. Nice job!

 

[88gmctruck]

After updating to my latest tune it has smoothed out some, between that and the ignition upgrade it seems normal now.

Anywho.......

Made a trip to Reno and back the other weekend, here is what my mileage ended up at on the way down. I managed to go over 9 on the way home.

The other day I finished out the airbox lid, cleaned it up and added a little touch to it.

Also installed new LED clearance lights and solar on the camper this past weekend.

Pulled the 88 out to shuffle some things around, figured this was a good opportunity to put them next to eachother. It's amazing they are 10 years apart. Love these trucks.

 

[88gmctruck]

Loaded up the quads and hit the coast.

On the way back I started getting a squealing sound which got louder and turned into a grinding sound..... Driver's side caliper decided to stick..... quick rest area pull apart and run to town for a new caliper... This is why it pays to travel with friends.

Made it home. Another issue I haven't touched on yet, as I wasn't sure if it was an issue, as a sound I started hearing in neutral. Kinda a bearing/rattling sound. It started getting louder on my trip to reno, and on this trip it turned into sounds while pulling hills as well... and downshifting. And it started shaking while taking off in 1st...........

All the same symptoms it had a year ago. Almost exactly a year ago. June 10th to be exact, is when I pulled the transmission from the truck.

So out comes the NV4500 fluid draining kit

Pulled my PTO covers to check the magnet......

Yup, that is metal. There should not be that much metal in a year/10k miles. After discussing this with a couple shops they are thinking I have a warped bellhousing, causing the alignment issue to eat up the end of the mainshaft. Lucky me, I've found the most cursed NV4500 on the planet.

Hopefully a new bellhousing and this will solve my problem.

 

[DieselSlug]

Ouch! Cant believe all the trouble that trans has been giving you.

 

[tanman_2006]

NV4500 life... They hate me too.

 

[Will L.]

Good time on the 4 wheelers!
Sux about the caliper and nv4500. I've got nothing against shifting- sometimes it more enjoyable. But they just have more problems than autos. We saw it in the fleets enough that only a couple drivers (lots of years on the job) that special requested them got them. Autos were just far cheaper because of down time and repair cost.

 

[tanman_2006]

Agreed, the nv4500 isn't bad and can be great but when they go bad they will really rack up the bill. An auto is in and out of the shop quicker and cheaper.

Fuel savings in pennies doesn't pay for a bad nv4500

 

[GM Guy]

and here I am over here having the best NV4500 luck ever... except for the 92-95 bellhousing. have a few of those that cracked.

@88gmctruck, I think I expressed curiousity when you went through it last year, I am curious if the bearings are high enough grade? I know quad4x4.com talks about some premium super duper grade of Timkens the general public and most suppliers dont have access to, dont know if its a line of bs or if its something worth looking into.

I need to learn how to dial in a bellhousing, I think they had a writeup in one of the diesel or offroad mags in the past year, being off a little is probably why so many of them have issues.

So yours kinda shakes as you accelerate in the lower gears? my high miled one with the cracked bellhousing does that a little, I better get it tore apart sooner than later I suppose.

As allways, great writeups, and even better work ethic on getting shit done on the truck.

 

[ak diesel driver]

How about seeing if a machine shop can fix it?

 

[88gmctruck]

Ouch! Cant believe all the trouble that trans has been giving you.

NV4500 life... They hate me too.

This one has been hell, then you look over at Devin's 96 that has almost 300k on it and has never been touched...

Good time on the 4 wheelers!
Sux about the caliper and nv4500. I've got nothing against shifting- sometimes it more enjoyable. But they just have more problems than autos. We saw it in the fleets enough that only a couple drivers (lots of years on the job) that special requested them got them. Autos were just far cheaper because of down time and repair cost.

Agreed, the nv4500 isn't bad and can be great but when they go bad they will really rack up the bill. An auto is in and out of the shop quicker and cheaper.

Fuel savings in pennies doesn't pay for a bad nv4500

I haven't heard of too many problems with the NV4500, seems i just got the bad apple of the bunch. The one I swapped into my 88 has given me no problems, it has all the original bearings in it, I just did syncros.

I don't know how an auto is cheaper or would have less downtime. Seems to me the downtime would be about the same, and the costs are same or lower on a NV4500 as long as you are going stock-stock. All said and done with this replacement, I'm $2,400 all in with a new trans and bellhousing.

and here I am over here having the best NV4500 luck ever... except for the 92-95 bellhousing. have a few of those that cracked.

@88gmctruck, I think I expressed curiousity when you went through it last year, I am curious if the bearings are high enough grade? I know quad4x4.com talks about some premium super duper grade of Timkens the general public and most suppliers dont have access to, dont know if its a line of bs or if its something worth looking into.

I need to learn how to dial in a bellhousing, I think they had a writeup in one of the diesel or offroad mags in the past year, being off a little is probably why so many of them have issues.

So yours kinda shakes as you accelerate in the lower gears? my high miled one with the cracked bellhousing does that a little, I better get it tore apart sooner than later I suppose.

As allways, great writeups, and even better work ethic on getting shit done on the truck.

I'm not thinking it's a bearing issue, TBH. I think the last set I put in it are Koyo bearings (japanese). In both cases the only bearing that failed was the one where the input slides over the main shaft - now both times I've had to replace the input and main shafts and they no longer make OE shafts for these so the only options are NOS, used or aftermarket. We are planning on tearing this down and rebuilding it for my father's 75 silverado - we will have time and I'm hoping to source some good used shafts.

In either case, I ordered a new (not rebuilt) transmission from midwest transmission. Lots of NV4500 knowledge and lots of dodge guys buy there. 12 month warranty. Let hope it lasts.

Not sure how you would even go about adjusting a bellhousing on a GM, there isn't adjustment to my knowledge.....

And it shakes, only when it's loaded and i'm taking off in first gear. it's the slop in the trans shaft walking around I imagine. If it's making noise in neutral, you have metal shavings, or it's shaking the damage is likely done. What I have learned on these, with exception of worn syncros, once it has symptoms the failure has started...

How about seeing if a machine shop can fix it?

Fix the bellhousing? I don't know if the BH or trans is the issue, but at $178 for a brand new GM bellhousing i'm just going to go that route.

 

[Will L.]

Granted, this is back a decade ago. 4l80e were $900 with converter. In the fleets we would put 300k+ on them and never touch the filter. Me or any of the guys could swap a trans in 3 hours, and have it back on the road. Figure seriously $300 and 1 hour labor per 100,000 miles at least. Half would go 500,000 miles and never be touched- just sell the truck. Zero down time or labor.

Never saw a pickup to 500,000 on a clutch.

 

[88gmctruck]

The 4L80E is a good trans no doubt, but you'll never get them for that cost anymore LOL. We did mine in 6 hours not really rushing, but wasn't bad at all.

-----------------------

Worked on the brakes late last week, ended up doing new Calipers, Rotors, and Ac Delco ceramic pads.

While I was waiting I got the wheels polished up. Photos don't do it as much justice, but the difference is pretty noticeable

My buddy also was due for brakes, so he brought his 98 over as well.

Got the transmission pulled. the input shaft was super loose, ended up popping it out and yup, exact same thing as the last go-round. Main shaft chewed up.

So, we checked the flywheel/crank for runout, there was none. my flywheel and clutch were perfect, there were still machining marks on them and no hot spots. Used a new oilite bronze pilot bushing, and just to make sure everything was good, a new bellhousing and brand new never ran NV4500.

So, it's together. New transmission is quiet and shifts tight and smooth. Lets hope this lasts...........