Chain in ATs

[BearZDefect]

Apparently some GM automatic transmissions have a chain. I don't know much about GM transmissions or BorgWarner. Not referring to CVTs here.

Is this all their transmissions or only FWD?

Why do they use a chain in an automotive transmission?

Do any other AT manufacturers use chains similarly? If the chain serves so well does everyone use it?

Thanks.

 

[Chris142]

I think the old FWD Cads and Olds from the late 60's had a chain.

 

[Axe Man]

1986 Chevy Celebrity with 2.8L V-6 and T440 O/D "junkbox" had a chain. At 86K miles the entire unit had to be replaced.

 

[swalve]

I thought all transverse FWD transaxles had a chain?

 

[bdcardinal]

Quote:

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I thought all transverse FWD transaxles had a chain?

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i believe the ford AXOD(E) has a gear drive. i remember dropping one out of a sable once and it had gears where the diff should be.

 

[74DartSport]

Quote:

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I thought all transverse FWD transaxles had a chain?

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My 97 Sebring 'vert (A604/41te) has gears.

 

[eljefino]

Pretty sure the 3t40 in my cutlass ciera had a chain.

They had lots of options for drive and driven sprockets to fine tune the final drive ratio.

Never a problem.

 

[Greaser]

http://www.vibratesoftware.com/html_help/html/Diagnosis/Reference/CVT_Transmissions.htm

 

[Gary Allan]

My mother's Citation had a chain. I couldn't figure out the noise before I sent her to a specialist

You would come to a hill or give it too much throttle and knk-kink-kink ..let up and it would go away. It was SO familiar ..but I couldn't place it. A while later I integrated it was the same as a loose bike chain (pedal kind) of my youth. I probably would have fixed it myself.

 

[CorvairGeek]

Apparently there was quite a problem with the early T125/3T40's, like in the Citation (X-cars). Don't recall hearing of it being an issue by the time J-cars and A-bodies appeared in '82.

 

[Earl Filter]

As far as GMs, there's a drive chain in all of the front wheel drive transaxles (at least all of the recent ones) that I'm aware of. GM rear wheel drive transmissions do not have a chain. Of the newer GM FWD transaxles, I've never seen the chain give a problem. I'm not a trans tech, but I was an advisor at a Chevrolet dealer, and saw the inside of many a transaxle. I don't even think they replace the chain as a matter of routine on complete overhauls.

 

[Earl Filter]

By the way, GM certainly isn't the only one using one in a FWD application. Ever seen the chain? Not exactly one that you'd find on a Huffy!

 

[BearZDefect]

Thanks for your responses, everyone.

I see a 'why' suggested: Easy to provide various final drive ratios.

All the direct 'yes' references so far are GM, so no other brands use a chain?

My questions are still about convention ATs rather than CVTs.

 

[carock]

100% of chain wear is caused by debris in the lubricating fluid. The chain slowly laps itself on the grinding compound in the oil.

 

[Earl Filter]

Quote:

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All the direct 'yes' references so far are GM, so no other brands use a chain?

My questions are still about convention ATs rather than CVTs.

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Definitely the Fords did/do too (old AXOD/AX4S for sure, and the newer ones too, I believe). As stated, some of the Dodges us a gear arrangement, but I don't know that they all do. I don't know what those crazy Japanese guys do.

 

[BearZDefect]

Thank you, everyone! If I find out more I'll post, but I haven't found much disclosure from transmission manufacturers out there.

 

[JTK]

Kind of funny. If the 'newer' GM FWD's do use a chain on the input end, gmpowertrain shows them so you can't see the chain: http://media.gm.com/us/powertrain/en/pro...20MN5%20LoR.jpg

Joel

 

[ikeepmychevytoo]

Had one in my '84 THM 125. Except the expected clutch set replacement at 120K mile no problems as of yet, even once throw to P at a slow speed while I was in the learning process, whilst coming to a halt car shaked vigorously many times back and forth. Harsh shifting but robust transaxles AFAIK. These especially known for their uncomfortably harsh N to D shifting, which corrected in the '85. So many impacting N to Ds are involved as well. Approaching to infitum my bet for the first replacement is the whining planeter gears.