I am planning to change my Allison trans fluid. I am still debating between synthetic and dyno. If I decide on synthetic, will I need to remove the pan, drain the convertor, flush the cooler ect. or will synthetic be compatible with the dyno oil currently there? http://www.dieselplace.com/forum/images/smilies/help2.gif

Why would uou want to change perfectly good tranny fluid? I don't know how many miles are on your truck but if it is an 05, it can't have too many. You should be able to go 40 to 50000 miles on stock fluid just change the spin on every 7000 or so. By the way, I asked an Allison tech if it was his truck, would he use transynd or dino. He said if you are using dino he wouldn't switch. My.02 maybe someone else has different idea.I am planning to change my Allison trans fluid. I am still debating between synthetic and dyno. If I decide on synthetic, will I need to remove the pan, drain the convertor, flush the cooler ect. or will synthetic be compatible with the dyno oil currently there? http://www.dieselplace.com/forum/images/smilies/help2.gif

Why would uou want to change perfectly good tranny fluid? I don't know how many miles are on your truck but if it is an 05, it can't have too many. You should be able to go 40 to 50000 miles on stock fluid just change the spin on every 7000 or so. By the way, I asked an Allison tech if it was his truck, would he use transynd or dino. He said if you are using dino he wouldn't switch. My.02 maybe someone else has different idea.If it were perfectly good (not sure how I would know without sampling and I havent), I would not change it. The fluid is starting to get a brownish tint to it. Smells OK, not burnt, but I dont like how it looks. I have around 11,000 miles on the original oil and feel that it sure wouldnt hurt to change it. I also plan to put a lot of miles on this spring/summer/fall pulling a FW at about 11,000lbs.

I am leaning towards staying with the Dino though, just so I dont have to worry about synthetic/dino compatibility.

Just looking for piece of mind I guess............http://www.dieselplace.com/forum/images/smilies/cool.gif

I dont think you would run into a compatibility issue but if you dont get all the old fluid out you arnt getting the benifits of synthetic. I believe there is a deccent write up in the DIY forum on how to do a flush and get all the old out.

BTW I run mobil 1 in mine and am a big believer in the stuff. I have seen some f ed up trans still have nice looking unburnt fluid even with crispy clutches. My stock fluid appeared as you described and I even droped the pan mid way through its life when I added a deep alli pan. dino will probably be fine though

I don't feel that there is any real issue of compatiblity when changing fluid from Dex III to a synthetic. At 36,400 miles when I first went synthetic (Amsoil ATF), I let the truck sit for 36 hours to "drain back" as much as possible. I then pulled the pan, pulled the suction strainer and replaced it after draining the fluid trapped above and removed and replaced my spin on. This was an easy way to get approximately 60% of the OEM fluid out of the system. After buttoning everything back up, I refilled with the syn ATF and ran it about 56,000 miles before repeating the process last fall for a second fluid change again using the Amsoil synthetic ATF. The drained fluid on the second change was clear and red and showed absolutely no discernable visual difference to the fresh fluid to be added. There were no traces of discoloration or indication of the comingled Dex III that had remained in the torque converter, cooler and passages. With the second change, my fluid is probably over 90% Amsoil syn at this point and continues to operate perfectly at 99,500 miles.

ratlover & Idle Chatter, Thanks for the information/advise. :ro)
When pulling the trans pan, is the gasket reuseable or should a new one be purchased prior?:cool:
How many quarts did you end up using to re-fill after dropping the pan.

Thanks Again....................:o:

gasket is reuasble

You can do a method that will pretty much get 100% of it out immediatly. You basicly yank the cooler lines and have it puke its guts into a bucket and refill it with new fluid. Syn or dino your choice.

I think it took me about 7-1/2 quarts to refill after popping the pan. The gasket is a large reinforced rubber unit and is quite sturdy. The pan is easily accessed, I've done both of my changes on the wheels working under the truck. I neglected to mention using the pan drain plug to get things started. It's recessed from outside, so there's a shoulder that prevents full drainage of the pan with the plug alone. Wipe out the pan and get as much of the black dust off the glued in magnet as possible. Wipe off the gasket and pan flange and make sure you start all the bolts and get the pan and gasket properly aligned before taking them all up finger-tight. The bolts have a 20 lb-ft torque spec, it's best to use a torque wrench and take them all up in a cross-fashion to that torque since the gasket is such a large and flexible unit. Torque spec for the drain plug is 26 lb-ft. Here's a shot of my pan when it was off last Fall. You can see how the drain plug in the upper right wouldn't fully drain the pan when attached. You can also just see the black square magnet that's glued to the pan under the fluid in the lower right hand corner.

.......The bolts have a 20 lb-ft torque spec, ........

I think the 20 lb-ft number for the transmission pan originally appeared in the transmission flush write-up, but it appears to be wrong.

The Transgo reference manual (on page 6) says "Torque pan bolts to 7 - 10 lb.ft.". In a recent post, Mike L said to go with the Transgo number rather than the 20 lb-ft number. There is also a post from about a year ago where a member said he stripped a bolt using the 20 lb figure.

i know alot of people recommend syn trans fluid if you live in the colder clitmates cuz it make for smoother shifts when the truck is cold. Thats just wut i have heard. I will probably be goin to syn.trans fluid.

I think it took me about 7-1/2 quarts to refill after popping the pan. The gasket is a large reinforced rubber unit and is quite sturdy. The pan is easily accessed, I've done both of my changes on the wheels working under the truck. I neglected to mention using the pan drain plug to get things started. It's recessed from outside, so there's a shoulder that prevents full drainage of the pan with the plug alone. Wipe out the pan and get as much of the black dust off the glued in magnet as possible. Wipe off the gasket and pan flange and make sure you start all the bolts and get the pan and gasket properly aligned before taking them all up finger-tight. The bolts have a 20 lb-ft torque spec, it's best to use a torque wrench and take them all up in a cross-fashion to that torque since the gasket is such a large and flexible unit. Torque spec for the drain plug is 26 lb-ft. Here's a shot of my pan when it was off last Fall. You can see how the drain plug in the upper right wouldn't fully drain the pan when attached. You can also just see the black square magnet that's glued to the pan under the fluid in the lower right hand corner.
Excellent information and picture.......................
Thanks for the help, torque specs, fluid amounts, pictures,......this information sure eliminates a lot of the risk on do-it-yourself maintenance.
Now all I gotta do is :grd:

I think the 20 lb-ft number for the transmission pan originally appeared in the transmission flush write-up, but it appears to be wrong.

The Transgo reference manual (on page 6) says "Torque pan bolts to 7 - 10 lb.ft.". In a recent post, Mike L said to go with the Transgo number rather than the 20 lb-ft number. There is also a post from about a year ago where a member said he stripped a bolt using the 20 lb figure.
Thanks for that important information, BH! I pulled the specs out of my Service Manual. I do have the Transgo Allison Manual here *somewhere* Now, the big question is what torque did I use myself last Fall?:rolleyes: I didn't strip anything - but it's tough for an old guy to remember these things when you've got that "Sometimers":D

Amsoil makes a syn. special for our trucks I switched it @ 50k. Torque Drive has performed great for me, I pull 10k 5er also.

I haven't been engaged in the Ally tranny forum for a while so I may be a bit rusty on my intel. :o: Noted you pull a 5ver with your truck which adds additional stress/heat to the tranny and fluid. IIRC synthetics tend to stand up to the heat better and not leave as much residue/film. :(

I opted to upgrade to Transynd ATF which is specifically made for the Allison tranny's, I believe Castrol(?) makes it for them. Great reviews/comments from all the DP guys that use it. I also went with the Allison deep pan (standard on the Allison 1000 except for GM) for an additional 3-4 qts of ATF. :exactly:

Surprised no one has mentioned the "Hoot" (IIRC) method for draining the ATF. Drop the pan and filter, refill with new fluid, disconnect the ATF return line and run truck for about 60 seconds to pump out old fluid in the TC, valve body and lines, shut off engine, top off with additional fluid and you will have about a 95%+- change out of old versus new fluid. I may have Censored the sequence but you can do a search and find it. :) Later. JJ :)

Amsoil makes a syn. special for our trucks I switched it @ 50k. Torque Drive has performed great for me, I pull 10k 5er also.
Is the Amsoil synthetic you are referring to called Torque Drive? Thanks

Is the Amsoil synthetic you are referring to called Torque Drive? Thanks
Yes

I drained at 15K and 30K and refilled with Mobil 1 ATF both times. I have also changed the filter every 10K. My next fluid change will be at 60K and I will probably continue to change at 30K intervals after that. I'm at 50K miles with no problems, including 10K plus miles of towing and 30K plus miles running the Banks 6G/SL.

I live in MI and the trans shifts the same at all temps, even when very cold. My old truck's 4L60E shifted much better in cold weather with syn ATF. I have also never had the trans go above 180-190 even when in stop and go driving on hot summer days.

Well worth the $$$ IMO.

Thanks to everyone for the information. Now I just need to decide.....synthetic or dino????????http://www.dieselplace.com/forum/images/smilies/confused.gif

At Autozone the other day, I saw a synthetic Dex III made by Castrol (Cant remember name). Has anyone used this or have any experience with it? (Castrol makes transynd, dont they?)http://www.dieselplace.com/forum/images/smilies/confused.gif

My prefererence is mobil 1 syn atf or regular dino with the pan dumped and new added fairly often.