Cummins 4BT & Diesel Conversions Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
32 Posts
Discussion Starter #1
Hello all,
I just recently joined this forum and thought you guys would like to see my GMC. It is mostly all original since being converted brand new from 454/t400 to it's current configuration. I bought the truck sight unseen, which was risky, but I was pleased to recieve a truck in good shape and relatively healthy except for a burnt valve. A remanufacted cyl. head,new oil lines for the remote filter and turbo, and new front brake hoses and I am rolling. It's not very pretty under the hood, but runs and drives excellent. I have another Brazillian turbo motor that has been configured for marine use that I will make nice and shiny in the process of configuring it back to fit the truck. Grigg, I have been following your projects and advice online for awhile, and admire your work and common sense approach. The junkman is also an infinate source of knowledge and good for a chuckle.
 

Attachments

·
Detroit Section Caretaker
Joined
·
3,761 Posts
Welcome!
And thanks for the pictures!
Looks like you've got a nice truck there, how long have you had it, and what year is it?
What did you say it has for transmission? How about axle gears?

Not the same truck, but a few years ago I had a 73 Chevy 1 ton that also had the 454 swapped for a 4-53 Detroit when only a year old. Wonder if it was done at the same place? probably a long shot, but I think my truck was from CO or perhaps TX, I picked it up a few owners later in CO, also sight unseen.
Thanks for the complement on my project, hope to get back to it soon, did install a shifter knob this evening.. most I've done in months :(

And don't forget Jim, he really knows his stuff on these 53 series and transmission swapping too.

Grigg
 

·
Registered
Joined
·
32 Posts
Discussion Starter #4
Thank you for your replies and complements Jim and Grigg. I have owned the truck for about ten months now, but just recently was able to get it running and driving. In my line of work, i'm away from home more than half the time,so it's when you can get to it. The truck is a 79 and the motor is a 78. I have every reason to believe it was new at installation. It came from Washington state and I have found items from Longview Diesel Service, a onetime Detroit dealer in the area. The guy I bought it from e-mailed me documentation that the conversion was done in 79 at a cost of 11,000 dollars, but I didn't recieve the paperwork when the truck came. It needs paint, but doesn't look real bad after 31 years! It still has the dealer sticker on the tailgate. The rear end is a corporate 14 bolt, but honestly I haven't taken the time to figure out the ratio yet. The transmission is a 5 speed manual, and I believe it to be a clark,but not sure. It could also be a spicer. There are no tags on the tranny, just a few random numbers here and there. It has a granny gear to the left and fwd, and reverse is all the way to the right and fwd. I was hoping you guys could help me i.d. it. I'll try to get some pics of it. It has no trans mounted e-brake. Tt uses the stock setup.
 

·
Registered
Joined
·
1,384 Posts
Is this Rob B from yahoo groups?
I saw the pictures of this truck on there.
It looks and sounds good after the valve fix.

I like the videos of your 4-51 on youtube.
Now that would be really unique, a 4-51 in a truck.

More pictures and videos are always welcome. :)

Chris
 

·
Registered
Joined
·
32 Posts
Discussion Starter #8
Alas, it is I! Thanks for the complement Chris. It's a fun truck. Hope everything is going well with your 6v project. I have some pics posted on yahoo of a 4/51 I saw, but don't own one. My father said they smoked like heck even when they were new, so probably not a good idea for the road! I believe they were only used in marine and industrial apps. in their
short production run. It's wierd to pull a valve cover and only see injector rockers!
Rob B.
 

·
Registered
Joined
·
32 Posts
Discussion Starter #9
After doing some research online and finding a page of shift patterns and pictures, I am confident that my transmission was manufactured by New Process Gear. I just don't know what model yet. Cast into the passenger side is the following : C 89510 S.
Rob B.
 

·
Registered
Joined
·
42 Posts
Got a link to the site and pics of yours? There were some of the NP trans installed in GM 2 ton trucks. Mid seventies are the ones I remember and they had a gasser 366 or 427 engine for power. The ratio split between 4th and 5th was a little too close as I remember them.
 

·
Registered
Joined
·
32 Posts
Discussion Starter #11
Funny that you mention that smalltruck. There isn't much of a difference between 4th and 5th. I'm still trying to figure out this forum. It won't let me post anything more than the three pics I posted initially. I guess I have to put them on webshots or something like that.
 

·
Registered
Joined
·
27 Posts
that shop was a detroit dealer and i know the guys that worked on stuff like that. it was a thing of the late 70's to repower these trucks. very cool
 

·
Registered
Joined
·
201 Posts
After doing some research online and finding a page of shift patterns and pictures, I am confident that my transmission was manufactured by New Process Gear. I just don't know what model yet. Cast into the passenger side is the following : C 89510 S.
Rob B.
Rob,
If your trans is in fact a New Process then it's likely to be an NP 542 . This was a Detroit factory optional trans in 1979 . I parted out a 4-53T that had one on it. NP offered the 542 with 4 different gear ratios. One even being a .85 overdrive while the others were direct in 5th.The O/D model is extremely rare and finding parts for any of them now can be quite a challenge. Do you have a tach in the truck? If you do you could do the math to find out if it's O/D or not.
If it is an NP 542 and the guys that did the conversion knew what they were doing then it's probably the NP 542D with gearing 6.15, 3.3, 1.86, 1.0 and 6.13 R. The O/D version has 6.15, 3.3, 1.86, .85 and 6.13 R. The other two 542's offered had a 7.24 first gear which would be a little steep for a pickup truck and in my opinion rather useless unless you plan on very heavy hauling.
Jim
 

·
Registered
Joined
·
1,658 Posts
Np-540, 541, 542's are just like an NP-435 w/ an extra gear. There was even a predesessor(non-synchro) to this trans-don't know the MN. Easy to bolt to a transfer case using an NP-435 stock rear adapter. Have to machine a snap ring groove in the tailshaft to retain the rear brg., though. They came in many trucks-Ford, IHC, Dodge. Stude, forklifts, other wierd stuff, watch out for worn shifter pins in the AL shift tower, Many had BIG input shafts, so watch out before you buy. Easiest way to ID-AL shift tower w/ 4 shift rails.

Predecessor to NP, now NV 4500.
 

·
Registered
Joined
·
32 Posts
Discussion Starter #15
Thank you Jim, I have a motorola 4000 rpm electric tach that is little more than a dash ornament at this time. It will be one of my next priorities. I doubt that mine is the od version because 4th and 5th seem closer than the specs you provided and 1st is very, very low.
Rob B.
 

·
Registered
Joined
·
42 Posts
Now that someone mentions it I remember the aluminum shift tower. It was a real POS because it wore fast and easily. If 4th and 5th are close it's not an OD model. The 1.86 and the 1.0 split would be okay. The split I remember was only about 300 engine rpm apart when shifting. Hmm old age has set in, Thats using a 2 speed rear axle so then thats the right ratio as I recall.
 

·
Registered
Joined
·
99 Posts
Rob,
If your trans is in fact a New Process then it's likely to be an NP 542 . This was a Detroit factory optional trans in 1979 . I parted out a 4-53T that had one on it. NP offered the 542 with 4 different gear ratios. One even being a .85 overdrive while the others were direct in 5th.The O/D model is extremely rare and finding parts for any of them now can be quite a challenge. Do you have a tach in the truck? If you do you could do the math to find out if it's O/D or not.
If it is an NP 542 and the guys that did the conversion knew what they were doing then it's probably the NP 542D with gearing 6.15, 3.3, 1.86, 1.0 and 6.13 R. The O/D version has 6.15, 3.3, 1.86, .85 and 6.13 R. The other two 542's offered had a 7.24 first gear which would be a little steep for a pickup truck and in my opinion rather useless unless you plan on very heavy hauling.
Jim
A lot of people say the NP542 OD is rare, but I'm not sure how? 'Bout all M35A2's have 'em, and those things were produced in the masses; the four trucks I have out back were 1500 each, and not incredibly hard to find.
 

·
Registered
Joined
·
201 Posts
A lot of people say the NP542 OD is rare, but I'm not sure how? 'Bout all M35A2's have 'em, and those things were produced in the masses; the four trucks I have out back were 1500 each, and not incredibly hard to find.
As far as I know the overdrive transmission in the M35A2 were not NP 542's . They were Spicer model 3053A. Not a bad transmission but I have heard some complain about the gear spread. And yes, it's one of the few "old school " medium duty overdrive transmissions readily available as a whole or parts.
 
1 - 20 of 20 Posts
Top