View Full Version : So my Allison is gushing oil now....

10-12-2010, 06:45 AM
So my 03 Siverado 2500 HD 4x4 started making a clunking when switching from forward to reverse and vice versa. Figured it may be a u-joint. Then moving 3 cords of firewood with our horse trailer (1 cord on truck, 2 in trailer), I could feel a wobbling when starting out from a standstill... Then on Friday we are heading to the coast for thanksgiving there was a vibration like a seperated tire. It got slightly worse by the time we got to Kamloops and then coming down hill into Merritt there was nothing when coasting but when any throttle applied intense vibration but slightly less when more under load. So I pull into Chevron in Merritt and tranny oil all over ground. So started it up to check oil level and oil just pours everywhere from underneath. So I look up underneath and between t-case and tranny but not right inbetween the two oil is seeping really quick from somewhere above tranny but right close to t-case on passenger side. So we had my father-in-law come up from Hope and he trailered it back to a shop in 100 Mile House so I will have it looked at today. I'm thinking a bearing went and the tranny case may be cracked.

So now I'm think already if a 6 spd allison will replace the 5 spd allison if I need to get a new or rebuilt tranny. Maybe an Atlas t-case too if its the t-case, lol. Either way I know its going to be a small money pit...

Aside from that a buddy told me his GM buddy that worked for GM said you should never flush an auto tranny because it can lead to failure, something about pushing the fluid back through the opposite way its pumped naturally by the tranny. Sounds crazy to me but I did have it done 50,000 kms or so before... best to just take pan oil off and drain the oil that comes out....

Anyone have similar Allison symtoms and how much it cost to fix??

10-22-2010, 06:50 AM
Nearly 2 weeks later and my mechanic was finally able to look at it... turns out a plate on the back top of the tranny was cracked clear across. So he contacted his supplier in Coquitlam and they say pull the tranny. So he is pulliong it out Monday and sending it down their to the pro's to have all the damage checked out and to see if its worth rebuilding. So it may cost up to $2500 for a rebuild or $4100 for a new allison. The new one comes with a 20K kilometer warranty if I buy new. So now the wait continues...

So if you have an Allison and get a vib like I did shut it down or hopefully take it in and have a real mechanic rather a service manager check it out. I did not mention it before but at 80 km/hr there was a definete jar when the tranny would shift. It was not normal and the service manager said it was nothing to worry about.... just venting...:mad:

10-22-2010, 08:41 AM
my 01 and 04 both shutter when shifting out of trans brake in tow haul mod under hi RPM. but my 01 would jump hard sometimes into 3rd gear felt like the whole truck came off the ground especially when i was hauling loads, when that tranny puked it cost me 9500.00 but i put a full on race tranny in it man i miss that tranny.....make sure you put a 3 stage torque converter in it and up the valve body pressure if nothing else. [cheers]

10-22-2010, 03:58 PM
i miss that tranny..... [cheers]

your bro always said you were "funny"

11-25-2010, 06:17 AM
So 5G later and an upgrade to the valve body in a new Allison 5 speed for better shifting when towing. U-joint closest to t-case (rear ds) was shot and mechanic said the vib from it (not a seperated tire as I thought) may have caused the tranny to go. Rear most bearing in Allison tranny was shot to the point it binded and cracked rear of case. If it was the u-joint that caused it why did the t-case bearings not go?? Maybe I miss-understood my mechanic...:confused0006: . I did run the tranny down 6 liters once when the tranny cooler leaked last year. Plus it had a vib\hard shift at exactly 80 km/h in the past... Maybe the u-joint broke the camels back??

11-25-2010, 10:37 AM
man that bites..... thanks for the details... i find it helpful when guys post things like this so i can be better informed about vehicles problems so i can avoid them myself...

hope it holds together for ya now!


11-26-2010, 08:24 AM
Don't we always learn things the hard way... If I was a mechanic on a daily basis maybe these kind of things would not happen. I can't believe I did not keep a better eye on my u-joints towing wood all the time.... The u-joint was well greased on 3 points but 4th point was all rusted ans cap was half gone. Sometimes grease goes two 3 points but not to the fourth. And a binded u-joint may not appear worn if testing for play still underneath truck...

11-29-2010, 07:28 PM
I have 96 silverrado and i think the transmission is on browroaded time start,s out fine but when at speed srage,s speedomader drop,s 20/30 km and it try,s to down shift let off and the speedow go,s back up it did this before chainged fuel filter at the same time the master silinder went problem stoped played in the snow the other day and it,s back the a.b.s came on for a bit then turned off not leaking flowed hard shift in 3 and cluk,s into R FOR RACE IT OWELY HAS 351.000

11-29-2010, 08:34 PM
i have a 2002 gmc 1500 4x4,cost me just under 9500 for a trans and transfer case last year ,when my buddys exact trucks tranny blew it took out the t case and rear end ,gotta love those chevy trucks after 160000k [cheers] oh ya from 2000 until mid 2003 they had major issues with chev trannys ,seemed to have fixed the problems now

11-30-2010, 05:22 AM
If your tranny is starting to show signs of wear and tear I'd get it checked before it become a big bill..... Aside from my tranny, my power extending mirrors no longer extended by power. Both mirrors cracked to sh*t. I was told by a freind at GM to junk them and buy two simple cheap ones. I wonder how much cheap simple ones cost? The turn signal in them and the defrost feature is really nice, plus adjust them from in cab. I wrecked one just after we got our truck and through icbc the mirror cost $900!!!:mad:

dirka dave
11-30-2010, 05:27 AM
Time to trade her in on a Dodge maybe ?


11-30-2010, 05:30 AM
Yah seriously. I wonder how much my 03 2500HDS 6.6 duramax 4x4 crew cab 4x4 is worth now. Wifey is complaining about money $$$ and I really like my 83 3/4 ton gmc 4x4 also. Its a long box, the 03 a short box:mad:

11-30-2010, 09:47 AM
for the miorr,s try pro body part,s :confused0006:

11-30-2010, 12:45 PM
Yah seriously. I wonder how much my 03 2500HDS 6.6 duramax 4x4 crew cab 4x4 is worth now. Wifey is complaining about money $$$ and I really like my 83 3/4 ton gmc 4x4 also. Its a long box, the 03 a short box:mad:

those trucks still go from about 15000 up to 25000[cheers]

12-01-2010, 02:16 AM
nope just the axil,s chev rule,s [36]

12-01-2010, 06:48 AM
Figured my truck is worth 20 at least. Buddy got me a price on mirrors for $120 each everthinfg except the automated extending option. $125 for a taillight too. The paint ion my truck has scratches from bushwacking and a few dents here and there. Spoiler is missing on front but it was coming off and getting the way of the tow hooks so I took it off. Bug deflector ...piece broken off. Tailgate handle missing but I just pull one of the rods to open it since one side does not latch anyways. Other than that it runs awesome. I put airbags in it and carrys are 8' camper nicely. Its paid for and is a nice truck to cruize to the coast with or for towing. My 83 chev 3/4 ton, has a worn 350 with a edelbrock intake (sucks fuel) , th350, and 4:10 gears, but sucks for towing. I'm sure it needs a new engine...

12-16-2010, 03:34 PM
just the speed sensor .not the trany.[36]