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Three blown trannys and i need some help

h0wl0ngcanitbe

h0wl0ngcanitbe

1/2 ton status
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Jun 2, 2008
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Washington
So heres the deal, i love k5 blazers, i just do, i think they are awesome trucks. i got an 86 k5 and ive poured over 27k into the thing between maintinace and upgrades i just cant stop! but in the 5 years that ive owned this thing ive gone through 3 trannys. ive only put less then 20k miles on the new 350 i put in 2004, but i keep blowin through trannys, im runnin 35x13.5 toyo open country mts, stock gears and a stock drive shaft the new tranny is im assuming a 700r 3 speed with overdrive whatever is supposed to be in thier. what do i gotta do to get this thing runnin right, i barely drive her and sometimes put her on the freeway. i just need some tips on what gears to run and stuff like that. also when i run down my current tires i would like to upgrade to 37 inch of the same type. i got a 6 inch skyjacker lift and an oversized tranny cooler but i dont think that will do the trick, any help would be awesome!
 
Ok well its what i got now, can i work with it? what are the cons to havin OD? i just think i need some new heavy duty gears to get this thing workin proper
 
First question: Where are you getting your tranny's?

Second question: What gears are you running?

Third question: How do you drive it? Do you drive it like a rental?
 
h0wl0ngcanitbe said:
Ok well its what i got now, can i work with it? what are the cons to havin OD? i just think i need some new heavy duty gears to get this thing workin proper
Click to expand...

Yes, you can use it, just drive it with the shifter in 3 not in OD. I would run 4.56 gears if you are going to use an overdrive tranny.
 
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i got an 86 k5 and ive poured over 27k into the thing between maintinace and upgrades

im runnin 35x13.5 toyo open country mts, stock gears and a stock drive shaft

i got a 6 inch skyjacker lift and an oversized tranny cooler
Click to expand...

4TH Question

How did you pour 27K into your rig? Thats a LOT of cash to have 35's, 6" lift, and stock drivelines and gears.:eek1:

Anyways for a 35" tire with the 700R4 4.56 will be optimal gearing. if you wanted to run a 37 4.56 would be ok, but 4.88 will probably help the low end out.

As mentioned earlier don't use the OD with stock (3.08 or 3.73) gears and 35's the tranny is probably hunting back and forth for overdrive which causes heat which causes failure. I ran my 700 for a few years with 37's and 4.11's and always just used drive. usually revs around 2700 RPM on the highway which is fine IMO.

Get 4.88's if you are upgrading in tire size.

You said you have a big cooler. maybe a tranny temp gauge to keep an eye on the temps.

If you are planning on running 37's and doing any type of hard wheeling i would suggest to upgrade to a 14 Bolt Full Floater for the rear and a 3/4 ton front or Dana 60 if you can find one in your price range before you re-gear half ton axles. The stock rear is typicaly the weak link with larger tires. The 3/4 ton front is the same as the half ton internally just with 8 lugs to match the rear, but will hold up to a 35-37 inch tire if you arent too hard on it and maintain it good.

Any other questions just ask:wink1:
 
i've seen plenty of people drive around with 700r4s and 35s on the wimpy stock gears (i'm referring to 3.08) with no problems. i run a 700 and 33s right now and i'm not gentle offroad. i'm really wondering if something is out of adjustment on yours.
 
The 700 R4 was not a particularly strong transmission. 3rd gear and OD were week IMO compared to the 350 & 400 turbo trans. There are several independant rebuilders that can beaf up a 700 R4 to hold up to off roading. It is also important to change the rear and front axle gears to 4.56 - 4.88 , and don't use OD off road or you will cook another tranny.
 
the plantetaries also dont like alot of torque and a heavy foot either with 35's and 4'11's i found out.
 
I drive her pretty good i dont stomp on her too much, i get my trannys from an ase certified autoshop, i think i got eith 3:08 or 3:73 whatever is stock
 
Thanks for the tips guys! so the consensus seems to be up it too 4:88 gears with 37s in mind on a 6inch with the 700r4. i know its crazy to think ive put so much into this rig with so little to show but i dont have the nohow so im at the mercy of tech shops and pros who like to stick it too a newb like myself!
 
Not to get unto your finances, but maybe you should look at investing your money in another shop. How much do you spend per trans? I bought a Stage 2, 700 from www.Monstertransmission.com and it only set me back 1100. No core, free cooler, stall converter, no core fee, and shipping included. These are the same guys that they use on Powerblock on SpikeTV. I figured they gotta be something!

Also are you certain your Kickdown/Detent/Throttle valve cable (same thing, just refered to differently) adjusted properly? If not, it will fry your trans in a heartbeat. Good chance this could be the root of your problem.
 
If you use 4.88 gears with the 700r4 and 37" tires at 60mph the engine will be turning 1862RPM.
2328RPM at 75MPH.
 
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I really have to question the quality of the rebuild or how they are installing it. Even with crappy axles gears and running the truck hard you should definitely not be going through tranny's that quick.

- Are they using a new torque converter each time? The one present when the trans originally failed will normally be full of debris and will cook the new trans is short time.

- Are they flushing out the cooler? If not you will either have it full of debris that will run through the new tranny and cook it, or even worse it will be blocked and allow the new trans to get super hot.

- Are they hooking up the TV cable properly? If not it will cause poor shift quality and will lead to premature trans failure.

In any case I would definitely find a new shop. Unfortunately having an ASE certification doesn't necessarily mean they know what they are doing.
 
Hey mtblazer89 i got a really stupid question but i gotta ask, third is what you mean by the third selection when you shift out of park as in one, two, three im in overdrive? overdrive is the one with the D in the circle im assuming. i just want to make sure that when i do put it into D its the proper gear for both freeway and inner city. i just ask cause on the streets it runs great, but on the freeway the rpm pushes mid twos but you said thats cool right? im just freaked cause i dont want to toast another tranny. Im gonna go with the 4:88 gears and when i replace my currant tires go to a 37" any other advice and thanks by the way!
 
No third gear is the D with no circle. OD is the D with a circle. You don't want to use overdrive around town, or it will help burn the trans out faster.

Consider going with a Bowtie Overdrives transmission, it will have all the upgrades. Then you can have your shop install it and probably get a good life out of it with new gears.
 
how hard is it to do your own gears?

So this is a general question is it hard to change out your own gears? I got my local off road co quoting me a but load on the change out. im lookin at stuff like on 4wheel parts and seein nice lookin gear packages for like less then 500. im just wonderin how tough it is to do it yourself, im pretty good with instructions but if i should leave it too pros i will.
 
thanks i know it sounds stupid but i wasnt sure so ill use D drive full time from now on. do you agree with the 4:88 gears and any other input too make my rig run good and strong?
 
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