Service? or not?

[raytwntrvlr]

Hope there someone here that can guide me on this one.
I just got my hands on a one-owner 2001 Silverado 2500HD with the 8.1 and Allison 5 speed tranny. It has 80K miles and unfortunately the gentleman who owned it is not available to answer my questions and there's no service records according to his wife.
Anyway, I just drove it 1400 miles to get it home and it virtually drives like a dream. Just a bit thirsty.
So, I have heard the advice that it's not good to service an old automatic transmission because it will cause problems.
However, I am one to get things maintained. I am guessing the old guy probably did service it but I just don't know. The filter is pretty dirty but the bottom of the engine/transmission is dry.

It does seem a little like if it aint broke don't fix it. I am pretty sure the GM garage I go to will advise me to service it but I want a second opinion before I go there.
So what do you guys think is the way to go with this?

TIA. Mike

[IBDAGRIZ]

Mike,

Lots of folks don't recommend doing flushes on older trannies, but do filter swap and fill instead. Leaves everything stuck in the corners, in the corners instead of floating and getting stuck in a smaller orifice.

That rarely causes any issues.

Griz

[MartinP]

Originally Posted by IBDAGRIZ

Mike,

Lots of folks don't recommend doing flushes on older trannies, but do filter swap and fill instead. Leaves everything stuck in the corners, in the corners instead of floating and getting stuck in a smaller orifice.

That rarely causes any issues.

Griz

Transmission oil wears out just like any oil, clutch packs, bearings, gears, heat, etc. If you look at the Allison manual it does give the oil change intervals. I believe 50K for mineral 100K for synthetic. In any case when in doubt call Allison.

[IBDAGRIZ]

Totally agree.
Does the manual mention flushing or just dropping the pan and swapping filters and re-fill? Usually that gets you about 35-45% of new oil in it each time.

My 2011 F-250 6 speed takes right at 8 qt's on just a drain/fill without dropping the pan to swap the filter on it. Right at 50% new fluid. Just did it last week before towing my TT for Thanksgiving.

Griz

[hzjcm8]

"I have heard the advice that it's not good to service an old automatic transmission because it will cause problems."

That's an old wive's tale. You can change the transmission fluid and spin on filter. But, that's like throwing out the baby with the bathwater. I recommend you let us (JG Lubricant Services) take a look at the fluid and transmission system through our Advanced Oil Analysis Kit. This can properly assess the overall "health" of the transmission fluid and the transmission internal parts. There's no need to change the pan filter.

If the analysis shows a change is necessary, then you'll want to use an Allison approved TES-295 fluid (see http://allisontransmission.com/parts-service/approved-fluids/on-highway-fluids).

Visit my thread at: http://www.irv2.com/forums/f125/form...eer-89293.html

[hzjcm8]

This might help !!

https://jglubricantservices.files.wo.../12/slide1.jpg

[Steve Ownby]

Originally Posted by hzjcm8

"I have heard the advice that it's not good to service an old automatic transmission because it will cause problems."

That's an old wive's tale. You can change the transmission fluid and spin on filter. But, that's like throwing out the baby with the bathwater. I recommend you let us (JG Lubricant Services) take a look at the fluid and transmission system through our Advanced Oil Analysis Kit. This can properly assess the overall "health" of the transmission fluid and the transmission internal parts. There's no need to change the pan filter.

If the analysis shows a change is necessary, then you'll want to use an Allison approved TES-295 fluid (see http://allisontransmission.com/parts-service/approved-fluids/on-highway-fluids).

Visit my thread at: http://www.irv2.com/forums/f125/form...eer-89293.html

Tom is giving you great advise here.

Bottom line is that there is no harm in a fluid change but it might be unnecessary. If you pull a sample & let J G analyse it. You will have a snapshot of the internal health of your transmission. This will also be a base line to compare future analysis to.

[hzjcm8]

Originally Posted by Steve Ownby

Tom is giving you great advise here.

Bottom line is that there is no harm in a fluid change but it might be unnecessary. If you pull a sample & let J G analyse it. You will have a snapshot of the internal health of your transmission. This will also be a base line to compare future analysis to.

Thanks for the kudos Steve !!

[MartinP]

[QUOTE=IBDAGRIZ;3924680]Totally agree.
Does the manual mention flushing or just dropping the pan and swapping filters and re-fill? Usually that gets you about 35-45% of new oil in it each time.

My 2011 F-250 6 speed takes right at 8 qt's on just a drain/fill without dropping the pan to swap the filter on it. Right at 50% new fluid. Just did it last week before towing my TT for Thanksgiving.

Griz[/QUOTE

The manual states to drain the pan and change the spin on control filter. The internal filter is only changed at overhaul however, my thoughts would be to change the internal filter if the pan needs to be dropped for the oil change as it is sitting right there. The oil change intervals can be as Allison states "optimized by the use of an oil analysis.

[Arch Hoagland]

I've owned two vehicles with the 8.1 engine and the Allison 1000 transmission. A 2003 2500 HD pickup and a 2004 Monaco La Palma.

Those years the Allison 1000 came with Dexron iii and a two year/25,000 mile fluid change interval.

Allison specifically says do NOT power flush the transmission. I always drained mine and refilled...ran it about 20 miles and drained it again and refilled it. That's the only way to do a complete fluid change.

About two years ago at 70,000 miles I switched the Monaco to Transynd. Won't be under there draining and refilling all the time.

If it was mine I'd drain and refill with Transynd. Do it twice. There is a spin on fluid filter on the transmission and I'd replace it too being sure to move the magnet from the old one to the new one.

[CountryB]

When you do a service drain and refill, you are not expected to refill with new fluid, drive some, and drain and refill again. That's a lot of extra work and money.

That extra step is not needed - unless you have some contaminants you are trying to remove.

If your switching from Dexron to Transynd, maybe its a good idea (I don't know) but it sure adds a lot of expense in the case of the big Allisons (which can hold over 40 quarts).

[Arch Hoagland]

Originally Posted by CountryB

When you do a service drain and refill, you are not expected to refill with new fluid, drive some, and drain and refill again. That's a lot of extra work and money.

That extra step is not needed - unless you have some contaminants you are trying to remove.

If your switching from Dexron to Transynd, maybe its a good idea (I don't know) but it sure adds a lot of expense in the case of the big Allisons (which can hold over 40 quarts).

On the Allison 1000 you need to do it twice as about three quarts are left in it that don't drain. Can't tell you about any other Allisons as I just have the Allison 1000.

[hzjcm8]

Originally Posted by CountryB

When you do a service drain and refill, you are not expected to refill with new fluid, drive some, and drain and refill again. That's a lot of extra work and money.

That extra step is not needed - unless you have some contaminants you are trying to remove.

If your switching from Dexron to Transynd, maybe its a good idea (I don't know) but it sure adds a lot of expense in the case of the big Allisons (which can hold over 40 quarts).

All,
Here's my recommended fluid/filter change procedures for Allison 1000/2000 Series and the 3000/4000 Series. Use this when fluid analysis indicates that the old fluid is DEXRON-III. The double drain and refill is intended to maximize the amount of the old sheared ("thinned out") fluid as possible. The fluid analysis will indicate the amount of deterioration (thinning) in the old fluid.
https://jglubricantservices.files.wo...-procedure.jpg

[jlckmj]

Service? or not?
Hope there someone here that can guide me on this one.
I just got my hands on a one-owner 2001 Silverado 2500HD with the 8.1 and Allison 5 speed tranny. It has 80K miles

To answer your original question, SELL IT TO ME ! I happen to be in the market for a beater (lol)

Jim