Hello, I just got back from dropping my truck off at the mechanic, RIGHT AFTER I GOT IT BACK. To start off, my old rear axle was whining, with the touch of the pedal, and it was also leaking, not by a seal, but by the actual housing right by the rear sway bar bushing. Since it was making noise, and my mechanic confirmed it was the rear differential, he recommended that the cheapest solution would be to replace it with a junkyard rear end. I called my local dealer, and found out that it was a 3.42 ratio with 7.625 ring gear. I then contacted my mechanic, and he found one with 48,000 miles.

I had dropped it off yesterday, and I just got it back a little while ago. It drove perfectly. All the whining noise had gone away, and there was no more clunking when shifting gears. After testing it for a few blocks, I decided I was going to make a turn on to a long straight way home. Therefore, I decided to test it in 4HI. I made the turn, and was probably going 15-20 mph, and I hit the 4HI switch while in Drive. Immediately, there was VERY LOUD CLUNKING, AND THE TRUCK IMMEDIATELY LOCKED UP AND BARELY WANTED TO MOVE. I put on my hazards, and called my mechanic. One of his guys came, and he managed to unlock it by switching gears and also in and out of 4x4. Then my mechanic sent me a flat bed, and the truck was taken back to his shop. He will be looking at it tomorrow, and will let me know tomorrow. But in the mean time, I would greatly appreciate and suggestions as to what it might be.

 

Different gear ratios. Your mechanic should have verified the gear ratio in the axle by actually reading what was on the ring gear in the current diff before getting the replacement. He also should have verified the gear ratio on the replacement axle before putting it under the truck.

 

Do you think it's possible that the transfer case is now damaged?

 

Well if you are lucky it may not be damaged, since the ratio's were not matched the clunking is from slamming in 4Hi, and not wanting to move would have been that the ratios were not the same therefore the rear was trying to push the front and the front holding back or vise versa, if you would have continued to try to drive with it in 4Hi it would have done some damage

 

wow you should defiantly post the mechanics info on here so no others may know not to trust this incompetent shop.

 

yup.

same rule as Kyle said. 'cause the wreckers may have made an error-either on shipping the wrong one after it was pulled, or didn't pull the right one in the first place.

and if the mechanic had done as was told by Kyle, then you wouldn't be in this mess right now.

any update on the problem/damage?

 

Sorry about not updating you guys on the situation. I have been busy with this problem and other things.

It turns out, that the dealer actually screwed me over this time, by giving me the wrong information. They told me that the gear ratio was 3.42 as I mentioned above. Since I told my mechanic, he took my word, and got that rear end. After this whole problem, and searching on here, I found out about the RPO codes, and found out that my rear axle is a 3.73 Positraction rear axle. My mechanic then ordered the right one, and I just got the truck back yesterday. I tested it, and everything works the way it should.

A few hours after I got the truck back, it started to snow here in my area. JUST IN TIME!!!!! LOL

 

this is a prime example of why you (meaning evryone) should learn how to get information themselves. if you had just taken the diff cover off, and read the 2 #'s on the ring gear, divided them into each other (ie; having this stamped on the ring gear "43:11" gives you 43 divided by 11 for a ratio of 3.91:1)

when you break as many diff's as i have, you quickly learn to make sure your replacement parts match what you are replacing.

glad to hear it was a relatively simple fix. now go enjoy the snow!

 

LOL I'll definitely do more research next time. Thanks to everyone for all your responses.

 

It still comes down to the fact that the mechanic should have verified any information that you provide before doing the work. After all, it is his reputation that is on the line. It is such a ****-poor excuse to say "the customer gave me the wrong info" when you have the truck right in front of you.