Hi all,thanks

Blazer k5 90 with 33'' tires and 4.56 ratio. 4x4 of course... :-D
i wish to correct the speedometer by replacing the teeth in the transmission..
but im having trouble locating them after someone told me that i would find what im looking for in the transfer.. can someone point me t the location of those teeth?
a pic would be very helpful i guess. 700R4 and np241 of course :-D

Thanks in advance, Yarin.

 

You don't have gears in your transfer case output shaft. You have a VSS (vehicle speed sensor) that uses a DRAC (digital ration adapter controller). A quick search on Google for "DRAC calibration" should get you the details you need to modify the DRAC & correct the speedo. It all starts with knowing where you started from.

 

i don't know what you meant when you said : "It all starts with knowing where you started from"... but i'll search for DRAC and see what i can find.

thanks.

 

You have to know what tires & gears that the DRAC is currently calibrated for (likely this is what the truck came with stock).

 

as far as i can tell we're talking about stock which is 235 tires (don't remember the inch for that size) ans 2.73? could it be?

 

am i right?

 

Only you can answer that question. What did your truck come with stock? Have you decoded the RPO/SPI label inside the glove box or gotten a printout from a dealer based on your VIN?

According to my references, both the 235/75R15 (28.9" diameter) & 31x10.5R/15 (31" diameter) tires were available on the 1990 4wd Blazer full size.


And you could have had 2.73 (PAW or PZX*), 3.08 (PAY, PBH, PBB*, or PBL*), 3.42 (PAX, PBT, PBC*, or PBM*), or 3.73 (PBA, PBK, PBD*, or PBN*) gears stock. Three letter codes found in in the parentheses are the codes that can be found on one of the rear axle tubes. '*' indicates that it originally came with a posi-diff. Of course, the axles could have been swapped at any point in time rendering these codes useless requiring you to look back to the vehicle VIN decode or RPO/SPI label.

 

hi,

i haven't done any work on the problem yet. i just wanted to ask if it's possible that it's related to a problem i have.
while cruising on a highway, if the road gets a little steep, the truck feels like it have a manual transmission and I'm pumping the clutch repeatedly. like the transmission is coughing or something. the truck gets very shaky and it feels like it's being forcibly stopped and released over and over again.
this only happens on the fourth gear, if i limit to third this won't happen.
it's a bit difficult for me to describe the problem, i hope i'm understood
love to hear your thoughts, this problem is getting too old

 

possible transmission problem the 700r4 was never known to be a strong tranny stock the sun shell and the 3-4 clutch packs are common failure points not sure if its your problem but check your tranny fluid for a brownish color and a burnt smell could be indicators of a problem internally.

Dont think it is related to your speedo problem.