http://www.dieselplace.com/forum/smileys/Ermm.gif It is about time to consider changing the dino fluid in my Allison to synthetic. Read all of the posts especially Hoots "Flush Procedure" - good info- not too hard.


Checking prices I can get Mobil 1 Syn ATF 5 gal for $79.50, TransSyn is $173 for 5 gal.


Checked with the local Detroit Diesel/Allison full service center and here is what they can do for me. Drop the pan and replace the internal filter with the new style, use a machine to complelty flush the converter, lines and cooler, (100% or very close to it fluid change), replace the external filter, fill with TransSyn, all for about $250.


When I talked to the technician who actually does the work he said he does this fluid change very often (says he has done lots of GM Allisions), the machine he uses really does a good job of flushing the entire system and he would guarantee an almost 100% fluid change. I asked about installing the deep pan at the same time - no problem. He did caution me that the pan hangs down lower and that he has changed out several short pans due to impact damage. He said if I watch where I drive I should have not problem. He will also use Mobil 1 if I bring it in - but he recommends TranSyn (No surprises here).


$250 for a complete change out using TranSyn without getting oily and dirty appeals to me. These guys have a very good reputation and I hate to take a bath in ATF like I do every time I do a complete fluid change.


What do you guys think? I can save a few bucks by using Mobil 1 and changing it my self or have Allison do it all with TranSyn. Have them change it out - does the price seem reasonable? What about the deep pan? I don't really tow very heavy loads so I don't think it is absolutly necessary but good insurance.


Comments and recommendations would be appreciated.http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

Going with the service center.. $250 + the cost of the deep pan... maybe addt'l fluid cost will get you up if not past $300.

You can do the job yourself for about $200

It's up to you if you want to save $100 or so. I think dmaxalliTech sells a kit which includes the juice. You would have to call him or email him as his site seems to be going under.

MikeEdited by: hoot

Shark Bait


What prompted you to decide to do the flush? GM recomendation? Mileage? or are you experiencing something in the tranny?

http://www.dieselplace.com/forum/smileys/Big Smile.gif MaineMax: I am considering the fluid and pan change for two reasons. Cold weather performance and protection. My truck is new and is working just fine - and I want to keep it that way.


Since moving to Alaska 22 years ago I have become a big fan of synthetic products in cold weather. They flow much better at low temperatures and perform well at higher temperatures. Had a lot of -20F to -25F days this winter. In fact the highest temperature I have seen on my Allison had been 140. A lot of days the temp would not even get above 100. 70 MPH at -25F keeps things cool.


Concerning the flush. I could just drain the pan and refill but that would only change out about 50% of the fluid. By having the Allison Service Center (or by using Hoots method) flush the system you will get very close to a complete 100% change of fluid.


I would not argue that you could run the original Dexron III for at least 50K miles, but for me the superior cold weather performance and the piece of mind synthetic products give me is worth the cost.http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

I vote Mobil 1. Second, Jerry at Mag Hy-tech and i did filter to pan measurements on deep oem Ally pan with deep filter and did not like the way filter moves out of case. The oem Ally deep filter depends on fluid mass(weight) to keep filter from coming out of the case too far. What if you play hard and bounce alot? Would it come out too far? If it does you lose a trans. I recommend MagHytech or PML deep pans. I have been involved in the measurment in both pans, both companys are top notch and your filters will not move.

It looks like the 2004 1/2 Allison has a deep pan. Later! Frank

http://www.dieselplace.com/forum/smileys/Geek.gif Frank:


Where did you see or here about the 2004 1/2 having the deep pan from the factory? Did GM offer any protection for the deep pan i.e a skid plate? http://www.dieselplace.com/forum/smileys/Question.gif

Shark Bait, thanks one more time for doing the leg work for me. I had planned on calling them this week to check on that but didn't get around to it. That price sounds pretty good for up here. Most places are charging around $120 to do a car auto tranny, just the flush and fill, no filters, and that's not using synth fluid. Figuring the cost of the TransSyn and filters, they really aren't charging you much for the labor. 20 years ago it would not have been a question at all. I'd do it myself. Now, I look at their labor charge and weigh that against what I feel my time is worth plus the hassle of disposal of the old fluid and the mess I know I'd make. To me, the scale is tipped way over in favor of letting them do it!! And, with the TransSyn, GM can't give you any warranty headaches.