'94 Silverado C2500 350 5.7 - high mileage question

[Adrian]

Hello all! I just joined this site and looking forward to checking it out. I have a 94 Silverado C2500 350/5.7 that has over 271,000 miles on it and is still running strong. I use it as a daily driver and also for my part time lawn care business. I pull a tandem axle 7x14 ft trailer with a walk behind mower and sometimes rock and mulch. Any thoughts on the life of these engines? I am not noticing any issues, but I think I have a small leak in one of the oil cooling lines b/c I have to put maybe a quart of oil in it every few weeks.

[diyer2]

A quart of oil every 2 weeks is not a small oil leak to me.

That's half a gallon of oil on the roads every month.

Properly maintained you could get a lot of miles out of that engine.

The tranny would be the biggest concern to me.

[Adrian]

Since you put it that way, that is a lot of oil. It may be closer to a quart per month, but thats still alot.

 

In regards to the transminssion (4L60E, I think), I had to replace both shift solenoids before 200,000 miles, along with transmission fluid and filter, and haven't had any issues in the last 71,000 miles. Are thoses transmissions good? 

 

**side note** when I bought the truck a few years ago, it was in almost excellent shape. Since then, it has taken a beating from my business, but not so much that I could fix it up for a fairly cheap price. Don't get me wrong: it's still a great looking truck being a '94 with no rust anywhere; there might be a little spot under the bedliner now that I think about it.

[Logan Lanfear]

If you change the fluids in the trans religiously then you might be set for a while but they dont last forever.  The 350 is probably feeling the miles as well but if the oil was changed regularly it should be alright.  Some people get 300,000 to 500,000 miles out of these but again, they wont last forever.  

[green 788]

That should be a 4L80 transmission (notice how Bruce Jenner has fixed it so we can't say tranny anymore without evoking that horrid image?)... :o    I ain't sayin' it anyway :/ ....   but the 3/4 ton truck should have the heavy duty transmission in it.

 

I just had to put new heads on my 350 engine at 102k miles.  But that was my fault for letting the catalytic converters clog, which blew the head gaskets and cracked the left exhaust manifold... keep those cats clean... with that many miles if you haven't changed them, they're probably getting clogged.   Time to replace, or "unclog" them.  :o

 

You've probably gotta be getting a little oil past the rings, which isn't a bad thing altogether... but it will contribute to the clogging of the converters too.

 

If you have that many miles on the 350 and don't have a check engine light... the bulb is burned out. 

 

Keep it moving, it'll keep going.  There are some around here with over 300k on them doing just fine.  They'll outlast two 454's if they're not abused.

 

Dan

[Adrian]

How would i know if it's a 4L80 or 4L60E?

 

my converter got clogged up/wasn't working a couple of years ago and I "fixed the problem"

[Logan Lanfear]

1 hour ago, Adrian said:

How would i know if it's a 4L80 or 4L60E?

 

my converter got clogged up/wasn't working a couple of years ago and I "fixed the problem"

Look at the RPO codes in the glove box.  I would be very surprised if it was the 4L60. Most likely the 4L80

[2018GMC]

5, 6 or 8 lug axles?

 

i have 205k on my k1500 350 / 4L60E. It’s now tuned and my daily. Tows a single axle 7x14 trailer at 3.5k lbs a few times a year camping. 

 

Truck runs great and and has been in family since new. 

 

Engine and trans original

upper and lower ball joints and tie rod ends original. 

 

whats what’s been replaced since new?

Besides the usual cap rotor and plugs?

 

flowmaster high flow cats

all 4 o2 sensors

radiator 

‘water pump

belt tensioner and idler

intake manifold gaskets

oil cooler lines

oil filter to oil cooler adapter seal

 

pitman, idiler arm and steering gear box. Now drives like new! 

 

transmission flush with valve line max life full synthetic

gear oil in front and rear diff

transfer case atf

 

anyway point is these are great trucks if taken care of :-)