techzone1047

Purchased a 2000 Yukon Denali a few months ago with 60K miles. When accelerating normally from a stop I notice a slight thumping feel for the first few feet (Imagine a transmission band slipping quickly three or four times before it locks up). All other shifts are fine and FWD is all normal. I took it to a trusted shop that specializes in tranny work who has taken care of my '95 Yukon for many years. He could also feel the problem. He went through everything from brakes, u-joints, etc. Found what he termed a fair amount of wear in the rear end. Something about spider this or that. He replaced as needed for a cost of around $200.00. Problem seemed better at first but may have been just my hopefullness as it is again very noticeable to me. If you were riding with me you probably wouldn't even notice it unless I pointed it out. Going on a 1000+ mile trip with 4000# trailer soon and am concerned. Any ideas?

bcopeland

I thought I had the same problem with my 2001 XL. I changed the rear differential fluid and thought it went away or got better. Not enough time to tell yet.

carrolmcc

I had the exact same problem with my 2001 4WD. My mechanic told me the spider gear was in shreds. Quote to replace was $2400. (that excludes new housing). My extended warranty will cover used replacement only. Is this a common problem with this car?

techzone1047

Thanks for the reply. Actually, I have found the problem and it is pretty simple. There is a service bulletin from GM that covers it. I think the number is #01-04-17-004. The slip yoke at the back of the transmission gets dry and when the length of the drive train changes during acceleration the yoke "pops" instead of moving smoothly. There is a new yoke available that is nickle plated that fixes the problem. P/N is 12477702 (1500 series) or 12477704 (2500 series). I was skeptical so I had my mechanic pull the yoke and put grease all over it. Completely cured the problem for about 5000 miles. Now it's back. They say the new yoke is around $200 plus .6 hours labor at a GM dealer. It's no longer a big worry so I haven't taken it in yet. Hope that fixes your problem also.

bcopeland

I just called one dealership here in Houston and they told me the lube job usually works (for $95) and they had done several of them and the customers do not return for the yokes. They mentioned the yokes are about $1,000 each! What's youir take on that?

techzone1047

Lube job didn't last very long for me. If I have the correct part number (I got the same number from three different sites) according to www.gmpartsdirect.com, the list price is $222.94 and their discounted price is $126.94. Go to this site and in the upper left corner is a search box. Type in 12477702 and hit search. Did your local dealer, by any chance, tell you what the correct part number is?

bcopeland

Yes - that's the right part number! By the way, if I order the part from GM Parts Direct, will the dealer still install it for me? Is it really hard to install? I can usually do these things myself. It looks like the end from the U-Joint into the differential.

techzone1047

Will the dealer install it? Probably not but most independent shops will. I have a copy of the service bulletin that I got from a forum site but I can't find the site now. It gives detailed instructions on how to replace the yoke. I printed it and would be happy to fax it to you if you don't have a problem posting a fax number. If you have a problem with that maybe you could post the fax number of your local Kinkos or Staples and I could fax it to them. I'm sure they charge for an incoming fax but it's minimal.

bcopeland

Can I give you the FAX number when I return to work next Monday?

techzone1047

Sure but I just found an easier way. Just click on techzone1047. It will give you the option to send me an email.

99DenaliMan

I have a 99 Denali. origionally, I took the car to Tuffy's (It's a local car shop). Before even test driving it, They wanted to start by doing a fuel injector cleaner, changing the clean air filter and going from there. LOL. I told em it was a driveline problem. Finally, I left in an argument. So, I do the next logical thing, I took it to the dealership, in which they lubbed the slip yoke coming out of the transmission. .8 hr.. To my satisifaction and amazement it fixed the problem. about 200 miles later it started happenning again. I took the vehicle back in to Keady's, Where they told me I need a new slip yoke. Knowing that to pull the driveshaft it takes two small 10 or 12 mm bolts to remove the whole thing. I decided to pull it and do the work myself. I changed the u-joints while I was in there. After I got the old one out and before putting in the new one decided to take a micrometer to both of the yokes. Again, to my amazement they where the same within .001 of an inch. I called keady's before install and they said "size doens't matter" that it has some material that wears off. My specific s/n was not one of the nickel plated ones. I went ahead and tried it, skepticle as I was it fixed the problem for about 2 weeks, once again, I go back into the dealership and they tell me there is a bulletin that says this is normal. The bulletin they gave me says "clunk when shifting gears". That was not my problem. my problem was upon stop and release of the brake. So, My problem is that the grease inside the slip yoke keeps dissolving and going somewhere. No matter how thick of fluid I put in or how heat resistant. To the same conclusion after a few hundred miles. "vibration-clunk". After reading this thread today I called them the dealership back up and asked him to look up my part #, He said he couldn't do that, only tell me what I should have. He said there are four different yokes for this 1 year? wow. and he could only tell my VIN #. So I ask everyone this. Obviously this is all to common a problem and the problem to fix permanitately must be fairly expensive otherwise GM would have come out with a Bulletin to fix the problem instead of a bulletin explaining why it's normal. fearing that GM owners may want a buy back or free fix. Anyways, as I'm going on about GM's terrible customer satisfaction, I guess my question is has anyone actually dug any deeper into the Transfer case/transmission to see exactly where the fluid is burning up or going too, and is there an easy fix such as a seal right inside the shell of the transmission, etc? Any information from some insightfull people would be greatly appreciated. Thanks and I look forward to viewing the other threads and discussing issues on this board.

99DenaliMan

Here's the update. I've contacted 1-800-GMC-TRUCK and they have promised to contact the dealer who said it was normal, and if in fact they kind find a fix for me they are going to fully reimburse the money I paid to replace the yoke and all the labor involved to find out what the problem was. Just F.Y.I. incase you where tld one thing then after getting charged told another they should reimburse you. If no fix is found on my next call back, I will leave name and EXT # to the GMC tech so all everyone here can lodge a complaint on this problem. Maybe, if we all tie up his line, Something will get done about this.

99DenaliMan

I've received permission from GMC to try something different, instead of having them pay me back for the repairs they did before they said "It's normal." I wanna kinda keep it on the low for now, but will update later with any results I get from my "testing and tuning" of my own vehicle.

99DenaliMan

UPDATE: we are in the final stages of what we feel will be a possible fix. Where just double checking a few clearances to make sure we dont must anything. Give me about 2 weeks and I promise I'll let you know what happens.

rmblack

I have a similar issue, yet the vibration is pretty constant when accelerating above 15 mph and seems to subside some over 80 mph. Is this most likely the same issue? It doesn't appear to be just when releasing the brake or at low rpm's. I have roughly 151k on my 2001 Yukon.