1988 S1853 gearing and probably other stuff

rwd4evr · 08-27-2019, 11:49 PM

I'm looking at trading my grumman 6.2 nv4500 Frito lay truck for a 88 s1853 bus. It's a 40' . Dt360 and 5 speed. He says he doesn't know the gear ratio and can't see the tag. Does the vin tell me anything? It's 2 hours away and I haven't layed eyes on it yet. Are these 5 speeds overdrive?
The vin is 1HVLPCFP5JH589851.
GVWR is 26,500, does anyone know the curb weight? My plan is to remove a good portion of the rear body and ramp it to carry my drift car or any other car I may be going to pick up so I'm curious on weight it actually is rated for carring not just the GVWR. I figure 72 passenger has to be at least 72 x 125# right?.

cadillackid · 08-28-2019, 06:44 AM

you can call navistar dealer with a VIN and ask for some "part" I need a 'rear gear' and they will give you a massively high price.. and you can ask "hey by the way whats the gear ratio? whats the trans model?" and they will tell you..

i am a huge fan of the DT360. esp when its paired to a locking transmission like an MT643 auto or a stick shift. thats likely a 5 speed spicer which is a good solid trans..

obviously make sure no one has trashed the clutch..

check the engine to make sure its solid.. no fuel or water in the oil ...

these are fully mechanical engines and can be rebuilt in-frame if you wear it out, there are things you cna do to turn up the A-pump and get youreself some more power.. a DT360 can be P-pumped if you want to make Real power..

im guessing since you mention a drift-car that you are mechanically inclined.. its a great platfoirm in my opinion to work on.

the DTA360 will rev to 2800 RPM but it runs most comfortably around 2300-2500 RPM..

-Christopher

Booyah45828 · 08-28-2019, 07:55 AM

Your local IH dealer should be able to tell you the factory gear ratio in the manner that Chris suggested.

You can also check on the inside of the hood on the right side by the radiator. Sometimes they would tape the factory line ticket right there(mine is). You can read through that and see what it is.

Your 5 speed is likely a direct drive unit.

Curb weight for a 40 footer with seats removed will likely be around 17k lbs.

A lot of racers have done what you're planning on doing so I see no problem with it. Try and place the vehicle's engine over the rear wheels of the bus for better handling. The only problem I've noticed is that the ramp angle is usually pretty steep because of how high the bus is off the ground. That might create problems loading/unloading with low ground clearance vehicles.

SolomonEagle · 08-28-2019, 11:13 AM

I have this same drivetrain in my '89 Thomas 28' dognose. The dt360 is awesome and super reliable as is the 5 speed. The tranny is 5th direct(no od). The gap between 3 and 4 is huge and I have to wrap it out in order to get it to pull In 4th. Certainly not a semi truck with a 10 speed. Also, though the engine can be turned up, I have refrained because the engine is already producing just under the torque rating for the tranny. Also, my bus weighs about 15k lbs. Though yours would likelly be lighter after you strip it down to make it a car hauler, your gvwr is the total allowed weight of the bus's and all it's cargo..so I assume you could tow a vehicle it the 10-12k range. This combo is no speed queen but is super reliable and probly more favorable than many of the power train combos out there short of getting a bigger engine.on the other hand, the Chevy 6.2 is one of my least favorite diesels of all time as I have had them fail under ridiculous circumstances. I say go for it

rwd4evr · 08-28-2019, 05:06 PM

Awesome ! Thanks for all that everyone. I'll call a dealer.

rwd4evr · 08-28-2019, 05:20 PM

Oops. .... .

rwd4evr · 08-28-2019, 05:22 PM

Quote:

Originally Posted by rwd4evr

I'm looking at trading my grumman 6.2 nv4500 Frito lay truck for a 88 s1853 bus. It's a 40' . Dt360 and 5 speed. He says he doesn't know the gear ratio and can't see the tag. Does the vin tell me anything? It's 2 hours away and I haven't layed eyes on it yet. Are these 5 speeds overdrive?
The vin is 1HVLPCFP5JH589851.
GVWR is 26,500, does anyone know the curb weight? My plan is to remove a good portion of the rear body and ramp it to carry my drift car or any other car I may be going to pick up so I'm curious on weight it actually is rated for carring not just the GVWR. I figure 72 passenger has to be at least 72 x 125# right?.

Yes I'm very mechanically inclined. I'm a hot roddder and been around race cars forever. I do equipment repair for a museum and work on some heavy machines. I do all my own work and design/fabrication on my 1978 Mercedes 450slc drift car, I sell vintage Mercedes parts as a part of my income. I've got some diesel experience with Mercedes stuff and I know all the theory just haven't put my hands on too many big trucks. It's only got 186,000 on it so I would guess it should have plenty of life left in it as is. We'll see if I get it.

rwd4evr · 08-28-2019, 05:30 PM

Quote:

Originally Posted by Booyah45828

Your local IH dealer should be able to tell you the factory gear ratio in the manner that Chris suggested.

You can also check on the inside of the hood on the right side by the radiator. Sometimes they would tape the factory line ticket right there(mine is). You can read through that and see what it is.

Your 5 speed is likely a direct drive unit.

Curb weight for a 40 footer with seats removed will likely be around 17k lbs.

A lot of racers have done what you're planning on doing so I see no problem with it. Try and place the vehicle's engine over the rear wheels of the bus for better handling. The only problem I've noticed is that the ramp angle is usually pretty steep because of how high the bus is off the ground. That might create problems loading/unloading with low ground clearance vehicles.

I've seen a couple with Jeep's or similar on the back. I was thinking if Dove tailing it behind the springs, or maybe a 4 link and air bags in the rear. The thought of a hinged Dove tail crossed my mind, I know the tail needs to be fairly high to keep it off the ground in a steep-ish entry way type situation. Im sure I can come up with something to make it work. My drift car is fairly low but there's always Jacking it up and putting blocks in for loading. I drive all over the place to pick up parts cars to part out so it would be used for that also.

rwd4evr · 08-28-2019, 05:36 PM

Quote:

Originally Posted by SolomonEagle

I have this same drivetrain in my '89 Thomas 28' dognose. The dt360 is awesome and super reliable as is the 5 speed. The tranny is 5th direct(no od). The gap between 3 and 4 is huge and I have to wrap it out in order to get it to pull In 4th. Certainly not a semi truck with a 10 speed. Also, though the engine can be turned up, I have refrained because the engine is already producing just under the torque rating for the tranny. Also, my bus weighs about 15k lbs. Though yours would likelly be lighter after you strip it down to make it a car hauler, your gvwr is the total allowed weight of the bus's and all it's cargo..so I assume you could tow a vehicle it the 10-12k range. This combo is no speed queen but is super reliable and probly more favorable than many of the power train combos out there short of getting a bigger engine.on the other hand, the Chevy 6.2 is one of my least favorite diesels of all time as I have had them fail under ridiculous circumstances. I say go for it

What is the rear ratio in yours? Im guessing you have the 11r22.5 tire right? So 2300-2400 rpm is what speed?

cadillackid · 08-28-2019, 05:55 PM

my bus has 11R22.5 tires and a 4.78 rear.. at 2300 RPM im running about 57.. I typically drive it 62 which is right about 2500 RPM..

you'll find the Bosch A pump to be similar to what you are used to with VW or merc mechanicals.. its pretty standard stuff. people can and do P-pump the DTA360.. MW pumps were on some of them.. but not as common as the A-pump.

SolomonEagle · 08-28-2019, 06:01 PM

I have 10r22.5s and 4.78 gears. Its been a while since I had it out on the highway but I think 2500 was 55ph as I remember. Think 2700 was 63+/- mph on the freeway. Nice thing the dt360 has over the 466 is a few hundred rpm capability

cadillackid · 08-28-2019, 06:20 PM

as the RPMs go up on the DT360 goes down the MPGs..

my most recent trip I caravanned with 2 other busses in which we set a speed of 62 MPH.. the front bus ran cruise control.. I gained almost 2 MPG over when I drive it at 65-66.. the engine fan almost never came on.. my temp never went above 185-190.. oil pressure held right in at 52-55 PSI.. and the engine just purred..

run it at 2700-2800 RPM and it sounds strained and racey...

SolomonEagle · 08-28-2019, 06:29 PM

Yeh, I prefer not to have to run it that fast but don't really feel doing it much harm. I only do that when I run it on the freeway. I found that I get 9 mpg wound out on the freeway with several mountain passes in my way..and right at 10 mpg when I run the highways at much lower speeds. More gear and overdrive (or equivalent) is on the list for sure. I would like to get a stronger tranny also so I can turn up the pump a little bit without worry

cadillackid · 08-28-2019, 06:39 PM

I was really surprised when i wasted my AT545 with a stock DTA360.. and that 545 was a perfect runner too...

once it died.. a 643 went in.. its a whoile different bus on the highway now.. I no longer really have a need to turn it up

rwd4evr · 08-29-2019, 02:14 AM

10mpg kinda sucks. But I was planning on running a good bit of wmo so that's not a huge concern. I get 13-14 towing my race car with my mountaineer. I haven't run the Grumman since it's got a wasted radiator but I've read they get up to 18 mpg with the OD nv4500. The motor is smoking too, bad injector I believe. The 6.2 is a turd though, a toy compared to the dt360.
I have a feeling this bus is around town geared looking at the speedo and the double line after 57mph. I found a 4.48 out of a later international but id like lower I think. Are there low 2 speeds around at all? That would be great. How about a rear with 19.5 low profiles? Get the back down some. Medium duty trucks all have the 34" frame right?

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Brad_SwiftFur · 08-29-2019, 02:52 AM

Instead of replacing the whole rear axle, it may be considerably cheaper and easier just the replace the "chunk" (carrier assembly) with one having the gear ratio you wish. Any heavy truck axle shop should be able to get (or rebuild) what you need.

cadillackid · 08-29-2019, 04:30 AM

My red bus has 19.5s but it’s a short wheel base. Too short for a hauler. There are handicap busses which have flat floors and low pro rear wheels.
You can gain a little adjustment for loading by finding a bus with air ride rear and dumping the air.. it’s a few inches at least depending on the amount of rear overhang your bus has.
There are low pro 22.5s made also..
You really don’t want to go too tall on the rear unless you plan to have enough gears of the right ratio to still climb hills. The DT engines don’t like to lug, they are worthless for power below 2000-2100 rpm but will cruise there as long as it’s not floored. The book says they peak at 2300 but I find 2500 to be where it seems to pull the hardest on hills. I only have 4 gears and my 3-4 shift(auto) is a huge drop in ratio.

For you I wonder if a 2 speed rear might suit you well. Low pro 22.5s and a 4.10 high and 4.44 low rear to give you more gear choices..
a firiend of mine did a full brownie box ..( just for fun. He enjoys the bus reatomod hobby like me). And that thing is a beast. So it’s 5 and 4. I believe the last 2 on the brownie are OD. There is some redundancy but I think we calculated he has 17 unique gears...he also swapped in a dt360. There isn’t anything that bus can’t do gear wise.
Christopher

SolomonEagle · 08-29-2019, 05:43 AM

The dt360 and 466 peak at different rpm. The 360 spins a little faster.mine hits 2800 no problem, though I try not to take it there!)

cadillackid · 08-29-2019, 06:13 AM

my 360 is tagged to peak at 2300.. max RPM is 2800-2900.. the navistar service book state it can be spun to 3200. but that "RPMS Above 2800 will shorten the length of service".. they do tell you how to adjust the governor.. the only reason i spoin mine fast than 2500 is because im slightly under-geared. for some of the traffic conditions I run into..

Ronnie · 08-29-2019, 07:17 AM

A note on gearing and tranmissions,

The NV4500 is real trouble prone for loosing 5th gear. the nut that holds it on the main shaft comes loose and 5th gear slides back out of contact, and just spins safely next to the speedometer gear. On the 4 wheel drive ones a spacer can be put in to stop this, but the 2 wheel drive ones have nothing behind 5th to stop it. Double nut has not helped me or welding the nut to the gear. All have failed. Check out the Dodge tuck forums for this.

Two speed rear, or brownie box are great for splitting gears so that you can keep the engine closer to it's best powerband. My bus has a two speed rear, my truck a 3 speed brownie(spicer 5831B) The two speed rear has better manners...but both do the job.

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