1988 GMC 3500K Sierra advice

[sologal70]

I have owned a 1988 GMC 3500K Sierra for many years. I want to buy a travel trailer and am wondering what limitations I should be concerned about. My thought is to "practice" hauling in my home state (Iowa) to shake down my future used travel trailer and before going on the road. I don't think I would want to use this old of a truck to do long distance trips. It has about 135,000 miles on it. Or maybe I'm being paranoid as I guess a new truck can have problems too. I guess I'm thinking as I practice camping more locally I will eventually run across a sale of a newer (diesel?) truck. Then I can tackle doing longer term trips.

I have a brake controller installed as I used it for my gooseneck horse trailer. It has a pretty heavy duty towing hitch (big springs). I had a friend pull a 30' sailboat from western Nebraska to Eastern Iowa one year.

According to the web, my wheelbase is 141.5" (club cab with full bed) which sounds like it can pull up to a 27' travel trailer. Does that sound correct? It is a 5.7 L V8 which according to charts is 185 hp (138kW) @ 4000 rpm 295 lb.ft (400 N.m) @ 2400 rpm. The GVWR is over 8500 lb. Is there other specs I need to know?
Kim in Iowa.

[rjstractor]

blt2ski wrote:
For those that do not remember. In 88 this was the first year for that body style. ALL 3500's were 8600 gvwr setups, ALL 2500's were a 7200 gvwr, and 1500's a 6600 gvwr. THERE WAS NOT a dually in this body style until 90 or 91. The 2500HD came out in 89 or 90 which only had a tbi 350, along with the 8 lug 8600 gvwr. The SW 3500 now had a 9200 gvwr. Then the dually came out it had a typical 10K gvwr with a 7500 grawr.

Good little history lesson by Marty, and a reminder of why to sometimes ignore the "3500" on the door. It may be a "1-ton" according to the number on the truck, but in reality it's the same as a later model 1500HD, except that it has WAY less power! Should be OK for 6K and under like Marty was saying.

[Michelle_S]

I had an '87 and a '95 1500 std cab 4x4 350 (5.7L) pulling a fairly light Fleetwood Prowler 24' TT. Don't recall the weight but lets say 5K loaded for a two week trip. We have a good grade leaving town next to a State Park and we would be in 2nd gear and thought we might end up in 1st before making it to the top. So we never dared to go any larger for fear of not making that grade.

[cpres]

88 c3500 big block powered dually owner chiming in, you know the condition of the truck and how it has towed other stuff. Yhe bottom line is it comfortable for you, I know these older trucks sure slow down uphill compared to new diesel-powered rigs, I travel and enjoy my old truck and no big payment.

[Thunderbolt]

blt2ski wrote:
Thunderbolt,
OP has correct hp torque specs. Motor was detuned for HD emissions.

Marty

I figured it was, but I wasn't sure. Thanks for the clarification.

[blt2ski]

Thunderbolt,
OP has correct hp torque specs. Motor was detuned for HD emissions.

Marty

[Thunderbolt]

A 1988 tbi 350 should be 210 hp and 300 lb ft of torque unless the 3500's are detuned. It is still nut up to the task of pulling a lot of weight. I pulled 5,000 with my 92 1500 with the 350 and it was working. Night and day between that and my 98 350.

[Grit_dog]

How reliable it will be is all in the condition of the truck and there are multitudes of variables there that no one here on the web could know or advise you as such. But being just shy of 30 years old and from the rust belt, unless it was/is a well kept, super maintained garage queen, I'd be Leary of its reliability for heavy towing or long distances.
As far as towing goes, you have enough chassis and suspension to tow more than the drivetrain will be happy with. I had a couple trucks with that 350 and would say anything north of 5-6klbs the truck will struggle.

[blt2ski]

For those that do not remember. In 88 this was the first year for that body style. ALL 3500's were 8600 gvwr setups, ALL 2500's were a 7200 gvwr, and 1500's a 6600 gvwr. THERE WAS NOT a dually in this body style until 90 or 91. The 2500HD came out in 89 or 90 which only had a tbi 350, along with the 8 lug 8600 gvwr. The SW 3500 now had a 9200 gvwr. Then the dually came out it had a typical 10K gvwr with a 7500 grawr.

Then if the OP is correct with WB, a 141 is a 6' bed, if he had an 8' bed as my 88 had, it would be a 155" WB. A BB in 88 had a dana 70, the 350 the Corp 14 bolt rear axel.

Anyway, max gcwr with this rig is 13500, unless he has 4.56 gears, which would put him at 15K. 3.73's would be 12500, and 3.42s 11500. Heaven for bid he has 3.08's, that would be 10500! The chassis will handle a larger trailer, but as noted, with a whopping 185hp, and not even 300 lbs ft of torque, he will be hurting in the power category from a speed standpoint. My 96 Crew cab with a 185/385 6.5 TD and a NV4500 did pretty good with a 6500 lb trailer, total gcw around 15K. but I was down to 35-40 on 3-5% grades in 3rd, ie gear below direct. That was a better towing tranny than the th400 or 4l80E auto setups, no matter the RA in it. 4.10s like I had were the cats meow from a gearing split stand point. If you had the munci 4sp, and 3.42's, your overall low, and high gear ratio were on par with the 4.10 nv4500. Pretty much from a performance stand point, equal.

marty

[KD4UPL]

In it's day that was a good truck for towing. It can handle the weight for sure, just light on HP.
I'm not sure how you're relating truck wheelbase to camper length but I think a 3500 long bed should be fine with a longer trailer. The overall problem is just that you will be quite slow going up hill. Expect to have your foot flat on the floor in second gear; or maybe even first gear if it's an automatic.
How much did the GN horse trailer weight? You should already have an idea what towing with this truck is like. An RV should give a similar experience but it will be less aerodynamic.

[Turtle_n_Peeps]

Kim you have good things and bad things going for you. The good thing is you have a big truck that can handle a bunch of weight on the tail.

The bad thing is you have a 100 LB weakling for an engine. Under a 200 HP is not a good thing.

Bottom line is this. This truck will pull a trailer under 9,000 lbs very well on a flat road. When you get into some mountains is when the trouble is going to start. Not so much trouble, but it will just take forever to get up a big mountain.

The lucky thing is there is not many big mountains in Iowa or in many states around Iowa. 🙂 So if your just planning on camping out around Iowa then you won't have any problems. I wouldn't want to come too much west of the western boarder of Ks though. Camp on!

[blt2ski]

With that particular 350, keep yourself under 6000 lbs loaded. Not sure of Adel ratio, more than likely a 4.10. Granny should be a th400 auto. Or if you have a manual, srm465 Muncie. Better of two granny options.
I had a long box ext cab and a 454 auto 410s, 2nd worst GM I've ever owned. Worst was a 89 R3500 flatbed.


Marty