Redline?

[sandmann999]

I just put a tachometer into my Bronco by replacing the guage cluster so I had a few questions.

First of all, what is the redline? I'm assuming about 5500. Secondly, what's the highest one should take it? It's '81 4.9 I-6. I looked at the tach and watched how I normally drive it. When I thought I was over-revving the engine, I was only at 2500 RPMs. Trying to figure out if it just gets loud and mean at higher RPMs or if it's only meant to be used in the lower 3000 RPM range.

Secondly, is there a decent way to change the miles on the odometer? I'm trying to reset the milage so that it matches my original odometer.

Thanks for any help.

 

[bluesman17]

ive only seen mine tap 4 grand....

 

[broncguy101]

ive only seen mine tap 4 grand....

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I put a tach in my bronc and its only reached 4 grand.

 

[Justshootme84]

sandmann, can you give some more info on the transmission- auto or manual??? WHile I havn't had the 86 up to speed, the 84 with a V8 and C6 auto will turn 3000 rpms at 60 mph. Redline on your 300 I-6 should be 5000-5500 rpms MAX, unless you've got some major mods on it.

 

[sandmann999]

sandmann, can you give some more info on the transmission- auto or manual??? WHile I havn't had the 86 up to speed, the 84 with a V8 and C6 auto will turn 3000 rpms at 60 mph. Redline on your 300 I-6 should be 5000-5500 rpms MAX, unless you've got some major mods on it.

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I haven't modded it at all. It's just a manual straight 6. I'm trying to figure out what RPMs I should rev to when I'm going up hills, cruising on the highway, stuff like that. My main reason is I usually go by sound on an engine and since this is my first truck, I'm not used to them sounding so....loud and powerful? at high RPMs, so I'm not sure if it's hurting it or if that's just the way it is supposed to sound.

 

[Justshootme84]

Check the door jam sticker for the tranny code, or better yety crawl ujnderneath the Bronvco and look for a nID tag or mumber, bmosquitoes are botheting my posts.

If you havea manual tranny, it will depend oon the model as to yor shift points.

 

[sandmann999]

Check the door jam sticker for the tranny code, or better yety crawl ujnderneath the Bronvco and look for a nID tag or mumber, bmosquitoes are botheting my posts.
If you havea manual tranny, it will depend oon the model as to yor shift points.

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Does C-2604194 sound like an applicable tranny code? There was another number that was a lot longer, but this one seemed more reasonable.

 

[Justshootme84]

The tranny code on the doorjamb sticker will be a single letter, like "M". IF you crawl under the Bronco to look at the tranny, look on the passngr-side for the New Process logo/ NP if it's a NP435. You can also look at the top of the tranny where the shifter mounts by removing the boot. The NP435 has an aluminum top cover. There is also a link to a tranny guide with pics from motivegear.com if you search for tranny info in the forums.

 

[Cl10racer]

Secondly, is there a decent way to change the miles on the odometer? I'm trying to reset the milage so that it matches my original odometer.

Sandmann, you could take the cluster apart and reset that way. I did mine in my '81 to 00000.0 to show that everything in the running gear is new.

 

[sreaminbronco]

I got mine to do 60mph. at 2000RPM but i dont know how.

 

[sandmann999]

The tranny code on the doorjamb sticker will be a single letter, like "M". IF you crawl under the Bronco to look at the tranny, look on the passngr-side for the New Process logo/ NP if it's a NP435. You can also look at the top of the tranny where the shifter mounts by removing the boot. The NP435 has an aluminum top cover. There is also a link to a tranny guide with pics from motivegear.com if you search for tranny info in the forums.

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On the door, the TRANS code is 'B' and the AXLE code (if it makes any difference) is '14'

 

[Justshootme84]

On the door, the TRANS code is 'B' and the AXLE code (if it makes any difference) is '14'

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THe trans code on my 84 is "K"=C-6 auto, on my 86 is "A" and I've ID'ed that one as the NP435 4-sp manual. I'm not positive what "A" is for, but can narrow things down some more for you. IF you have a 4-sp without OD, it may be a Warner T-18 or T-19. IF it does have OD, it may ba a SROD or TOD. The Haynes manual shows where the ID tags are located and that tranny guide from motivegear.com has pics and descriptions as well. It would still be advisable to visually ID the tranny, since it may not be the original unit.

www.motivegear.com

I believe the rear axle code "14" is a Ford 9" with 3.08:1 gears and no L/S. That does make a difference, especially if you put bigger tires than stock on your Bronco.Again, I would look for a nID tag either on the front axle or rear or both, and see what type of rearend the Bronco has. With that info, you can determine your final drive ratio in any gear and estimate your shift points. THe 300 I-6 will be screaming at 60 mph with 35" tires at about 3000RPM. You will prolly have to rev up to close to 2000 RPM before shifting gears if you want to get up to speed very fast, or just tool around in 2nd most of the time. Changing the axle gear ratio will help a bouch with the power loss from taller tires.

 

[sandmann999]

Thanks for all of the info. It turns out that the transmission is an SROD I'm assuming, because it has a RUG code in it's ID tag. Other than that, there wasn't any other information on there that I recognized or had to do with the ID numbers on motivegear.com. It's a 4 speed with 4th being overdrive where shifting into rear requires that the shifter be pressed down and then to the left and up.

What is the gear ratio for that transmission (and where is this information available to look up?)

The information about the tires is good to know. I was planning on putting bigger tires on it to increase the ground clearance. Right now, it only has 30x9.5s. I was thinking about going to 32 or 33 x 10.5s sometime in the future.

Again, thanks for your help.

THe trans code on my 84 is "K"=C-6 auto, on my 86 is "A" and I've ID'ed that one as the NP435 4-sp manual. I'm not positive what "A" is for, but can narrow things down some more for you. IF you have a 4-sp without OD, it may be a Warner T-18 or T-19. IF it does have OD, it may ba a SROD or TOD.  The Haynes manual shows where the ID tags are located and that tranny guide from motivegear.com has pics and descriptions as well. It would still be advisable to visually ID the tranny, since it may not be the original unit.
www.motivegear.com

I believe the rear axle code "14" is a Ford 9" with 3.08:1 gears and no L/S. That does make a difference, especially if you put bigger tires than stock on your Bronco.Again, I would look for a nID tag either on the front axle or rear or both, and see what type of rearend the Bronco has. With that info, you can determine your final drive ratio in any gear and estimate your shift points. THe 300 I-6 will be screaming at 60 mph with 35" tires at about 3000RPM. You will prolly have to rev up to close to 2000 RPM before shifting gears if you want to get up to speed very fast, or just tool around in 2nd most of the time. Changing the axle gear ratio will help a bouch with the power loss from taller tires.

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[Justshootme84]

Sandman, I find alot of links and info at the miesk5homepage, with a link posted in the Tech Articles forum. You won't find much info on the SROD in the tranny guides, so check out this super article from gearzone.net:

gearzone.net/toploader

There are two possible gear ratios for your Bronco, and I would assume the taller gears (higher number 1st gear) is what you have. Either the 3.01 or 3.25 ratio is not too bad, compared to the granny low of about 6.69:1 in my NP435, and I think you can estimate shift points and final drive ratio with either set of gears. You can find any formulas you need in that Miesk5 link. If you want to add 33" tires, a 4.10:1 gear ratio in both axles will get your motor back into the proper powerband to pull them. Didn't think a simple tach install would be so involved!!!

 

[sandmann999]

Sandman, I find alot of links and info at the miesk5homepage, with a link posted in the Tech Articles forum. You won't find much info on the SROD in the tranny guides, so check out this super article from gearzone.net:
gearzone.net/toploader

There are two possible gear ratios for your Bronco, and  I would assume the taller gears (higher number 1st gear) is what you have. Either the 3.01 or 3.25 ratio is not too bad, compared to the granny low of about 6.69:1 in my NP435, and I think you can estimate shift points and final drive ratio with either set of gears. You can find any formulas you need in that Miesk5 link. If you want to add 33" tires, a 4.10:1 gear ratio in both axles will get your motor back into the proper powerband to pull them. Didn't think a simple tach install would be so involved!!!

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Hehe, yeah, came out to a lot more information than I originally anticipated! Although, it's great stuff to know and I was curious about all of it anyway, so it's great. Also, unless I missed it somewhere, you mentioned the Miesk5 link, but I never saw a link to it. Is that the gearzone.net one, or a different one?

Thanks again for all your help!

 

[Justshootme84]

Look in the "How-To Tech Articles & Reviews forum here at Bronco Zone. THe Miesk5 link is the first topic, and it's pinned so you ca nalways find it. I would add it to your favorites, too.

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