On Monday my truck is scheduled to go under the knife to get her new ring and pinion gears put in. I'm swapping out my OEM 3.42's for Yukon 4.11's and an Eaton Posi.

I have a Westers PCM and I have had Lyndon send me a re-burn taking these gears into account.

I have had the gear swap scheduled for 3 weeks, and I ordered my re-burn from Lyndon 2.5 weeks ago. Its not here yet. I called him Friday to ask about it, and he told me that UPS was going to pick it up that day (Friday the 11th).

Here is my problem:

My truck goes in Monday at 8 AM for the swap. I had to schedule almost a month in advance because Monday is my only day off. That means at the VERY LEAST I'll have to drive my truck home (approx 20 miles) without having the PCM programed for the gear swap.

I know it will throw codes, and I know my spedo will be WAY off. My question is:

Will it hurt anything? What if the PCM doesnt come in Monday then the truck has to go to work with me on Tues (40 mile round trip). Will that hurt anything?

Input? Thoughts? Suggestions?

(If I reschedule it'll be over a month before I get them put in, i'll do it if I have to, but its a last resort)

 

i drove mine for a while without the right tune in it. didnt hurt mine.

 

Nothing should happen to it and it should not set off any codes. Your speedo will be off a bit.

 

i have been driving mine for a while too without the speedo correct. i went from 3.42's to 3.73's. at 55 and under it was 5 mph off. and from 60 on it was about 10 mph off. meaning if i was going 55 i was really doing 50.

now i have a tune in for 4.10 gears and haven't done the change yet. my speedo does the same thing just in the opposite side. i go 50 on the speedo and actual speed is 55. hope this helps ya.

oh yea, no codes were thrown.

 

Good Deal thanks guys.