Tranfer case grind and gas mileage
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Tranfer case grind and gas mileage
I recently purchased my 78 stepside to relive my youth i paid 5 grand and i dont care if it was to much . In the 90s i paid 900 bucks for a 2 wheel drive Warlock and i loved that truck to .
Currently i believe its my tranfercase grinding in first and reverse . I dont know much about the 4 wheel drive system but will do what it takes to make it correct will start tomorrow with checking fluid
Also i am getting 9.4 mpg thats a kick in the wallet . current holley 600/650 needs adjustment running rich will get to the bottom of that issue quickly considering changing gear ratios .does any body have an easy formula for figuring out transmission gear ratios to differentials and tire size to compute engine rpms that i would like to drop .
1978 w150 360 4sp
so my 2 questions
whats grinding in 1st and reverse and whats it take to fix
and gear ratio to rpm formula for best differential gears to improve mileage
Currently i believe its my tranfercase grinding in first and reverse . I dont know much about the 4 wheel drive system but will do what it takes to make it correct will start tomorrow with checking fluid
Also i am getting 9.4 mpg thats a kick in the wallet . current holley 600/650 needs adjustment running rich will get to the bottom of that issue quickly considering changing gear ratios .does any body have an easy formula for figuring out transmission gear ratios to differentials and tire size to compute engine rpms that i would like to drop .
1978 w150 360 4sp
so my 2 questions
whats grinding in 1st and reverse and whats it take to fix
and gear ratio to rpm formula for best differential gears to improve mileage
Last edited by javapower; May 23, 2012 at 11:30 PM. Reason: adding model and engine size
Admin
Joined: Apr 2008
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From: Goffstown, NH
Welcome!
Do you know which tranny you have? I know you said 4spd but the model is what is important. It could be an NP435A or an NP435L. The big difference is 1st gear ratio. the "A" model has a 6.68:1 ratio where as the "L" model has a 4.56:1 ratio.
As far as the grinding going, if you hear it in first and reverse only, then it may not be the t-case (could be NP208, NP200, NP203 or NP205). Have you tried to go slow in 2nd gear to see if you hear the same grinding noise? If you did not hear anything, then I would start looking at the tranny itself. Pull the plug and see if you have any metal shavings in the fluid.
For the carb adjustment, talk to "rickyr" on here as he is a tech for Holley and knows Holley carbs very well.
For a calculator you can go here - http://www.rocky-road.com/calculator.html - or here - http://www.grimmjeeper.com/gears.html - but you'll need to know which tranny, t-case, axle ratio and tire size you have so that you can put in the proper ratios. Do you know what axle ratio you currently have now? What tire size are you running?
Do you know which tranny you have? I know you said 4spd but the model is what is important. It could be an NP435A or an NP435L. The big difference is 1st gear ratio. the "A" model has a 6.68:1 ratio where as the "L" model has a 4.56:1 ratio.
As far as the grinding going, if you hear it in first and reverse only, then it may not be the t-case (could be NP208, NP200, NP203 or NP205). Have you tried to go slow in 2nd gear to see if you hear the same grinding noise? If you did not hear anything, then I would start looking at the tranny itself. Pull the plug and see if you have any metal shavings in the fluid.
For the carb adjustment, talk to "rickyr" on here as he is a tech for Holley and knows Holley carbs very well.
For a calculator you can go here - http://www.rocky-road.com/calculator.html - or here - http://www.grimmjeeper.com/gears.html - but you'll need to know which tranny, t-case, axle ratio and tire size you have so that you can put in the proper ratios. Do you know what axle ratio you currently have now? What tire size are you running?
Mopar Fanatic
Joined: Sep 2009
Posts: 486
Likes: 29
From: Amarillo, Tx
Just a quick thought on the "grinding" in 1st and reverse... Bet its the non-syncro granny geared trans (ie:'Truck' trans), which ever one that is, and non syncro reverse is also 'normal' for that type of trans. I would FIRST check clutch adjustment to make sure it is completely dis-engaging... Nice truck btw, and there are answers around.... There sould be a tag riveted to the transfer case for ID purposes, and there maybe still a tag on the rear end for the ratio as well, it will be bolted under one of the cover bolts, or if its a drop out style should be under one of the nuts.
Admin
Joined: Apr 2008
Posts: 8,173
Likes: 200
From: Goffstown, NH
Thread Starter
New Member
Joined: May 2012
Posts: 3
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Welcome!
Do you know which tranny you have? I know you said 4spd but the model is what is important. It could be an NP435A or an NP435L. The big difference is 1st gear ratio. the "A" model has a 6.68:1 ratio where as the "L" model has a 4.56:1 ratio.
As far as the grinding going, if you hear it in first and reverse only, then it may not be the t-case (could be NP208, NP200, NP203 or NP205). Have you tried to go slow in 2nd gear to see if you hear the same grinding noise? If you did not hear anything, then I would start looking at the tranny itself. Pull the plug and see if you have any metal shavings in the fluid.
For the carb adjustment, talk to "rickyr" on here as he is a tech for Holley and knows Holley carbs very well.
For a calculator you can go here - http://www.rocky-road.com/calculator.html - or here - http://www.grimmjeeper.com/gears.html - but you'll need to know which tranny, t-case, axle ratio and tire size you have so that you can put in the proper ratios. Do you know what axle ratio you currently have now? What tire size are you running?
Do you know which tranny you have? I know you said 4spd but the model is what is important. It could be an NP435A or an NP435L. The big difference is 1st gear ratio. the "A" model has a 6.68:1 ratio where as the "L" model has a 4.56:1 ratio.
As far as the grinding going, if you hear it in first and reverse only, then it may not be the t-case (could be NP208, NP200, NP203 or NP205). Have you tried to go slow in 2nd gear to see if you hear the same grinding noise? If you did not hear anything, then I would start looking at the tranny itself. Pull the plug and see if you have any metal shavings in the fluid.
For the carb adjustment, talk to "rickyr" on here as he is a tech for Holley and knows Holley carbs very well.
For a calculator you can go here - http://www.rocky-road.com/calculator.html - or here - http://www.grimmjeeper.com/gears.html - but you'll need to know which tranny, t-case, axle ratio and tire size you have so that you can put in the proper ratios. Do you know what axle ratio you currently have now? What tire size are you running?
I checked fluid It was full both tranny and transfer case .did not pull plug not check for shavings .convinced its it tranny probably going to tranmission shop .all tags are missing . no noise going slow in second .im geussing its a np 205 is over drive an option?
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progress
I found tag on 4 spd . DL96 435
And stamp on transfer case wc-11890 I believe it to be np203 .can anybody confirm
No tags on differentials . trying to figure out gear ratios . can a person spin a wheel and count drive shaft revolutions to get in ball park .I am over 3000 rpm at 65 /70 getting 9.4 mpg is tough on pocket book
My main concern today is to keep truck on road .when i purchased truck from nice kid in wisc . Transmission had " significant whirring and vibration in first and reverse " previously i discribed as grinding .this was explained by him as the low gearing . Uncle buck disagrees and believes catastrophic failure is eminent
Thanks Garold
And stamp on transfer case wc-11890 I believe it to be np203 .can anybody confirm
No tags on differentials . trying to figure out gear ratios . can a person spin a wheel and count drive shaft revolutions to get in ball park .I am over 3000 rpm at 65 /70 getting 9.4 mpg is tough on pocket book
My main concern today is to keep truck on road .when i purchased truck from nice kid in wisc . Transmission had " significant whirring and vibration in first and reverse " previously i discribed as grinding .this was explained by him as the low gearing . Uncle buck disagrees and believes catastrophic failure is eminent
Thanks Garold
Admin
Joined: Apr 2008
Posts: 8,173
Likes: 200
From: Goffstown, NH
You definielty have a NP435 tranny. Which model (A or L) you won't be able to tell unless you drive it or pull it out, put it into 1st gear, rotate the input shaft and count how many times it takes to get the output to spin once.
As far as the rear axles go, lift the back end of the truck, set it on jack stands, chock the front tires, remove the driveshaft, spin the yoke and count how many rotations it takes to get one of the tires to spin once. This will give you an estimate about what your gear ratio is.
Another way is to pull the rear diff cover and rear what it says on the ring gear.
I'm going to go ahead and agree with Uncle Buck on this one and say that you will probably need to rebuild (~$300 for the kit) or replace the tranny. A shadetree mechanic can do a rebuild on these trannies as they are fairly straight forward and easy.
As far as the rear axles go, lift the back end of the truck, set it on jack stands, chock the front tires, remove the driveshaft, spin the yoke and count how many rotations it takes to get one of the tires to spin once. This will give you an estimate about what your gear ratio is.
Another way is to pull the rear diff cover and rear what it says on the ring gear.
I'm going to go ahead and agree with Uncle Buck on this one and say that you will probably need to rebuild (~$300 for the kit) or replace the tranny. A shadetree mechanic can do a rebuild on these trannies as they are fairly straight forward and easy.
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