Mail trucks used some form of THM trans. I assume it was a 350. Didn’t they also use a Powerglide for a while? I’ve seen old Powerglides take a lot of abuse. A buddy had one and bypassed the cooler because his trans cooler line leaked. Drove for years that way.
Longest lasting OEM Automatic transmissions?
- Thread starter LenZee
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The postal LLV's use the TH180/3L30 and have all the same inherent problems they had in other passenger vehicles.
AutoMechanic
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Usually Motorcraft or Castrol Mercon V which seems to be hard to come by these days. I think you can use regular Mercon in it too which is probably extinct these days. We have done that and besides the minor slipping it has been flawless and the LubeGard took care of the slipping no problem. That’s excellent with 19,800 miles ours is at 141,000. We usually do 30,000 to 40,000 on it we changed it a bit early this time around since it’s getting cold outside and we don’t have a garage at home. I too heard horror stories about the transmissions but according to the transmission guy the reason for the issues is negligence of taking care of them people just leave the fluid in them and run it to the ground. If you have any other questions feel free to ask. We are very happy with ours we’ve only had to do general maintenance on it.
I have a 96 with close to 200K on it and I've been using regular Dex/Merc and changing every 15K to 20K. Walmart has Valvoline Dex/Merc in the blue gallon jugs for a reasonable price.
A 94 should have a drain plug in the torque converter so you should be able to get about ~12 quarts out for each change.
A 94 should have a drain plug in the torque converter so you should be able to get about ~12 quarts out for each change.
Like Ripcord said.....They used a 3L30 which is actually a European Hydramatic.
Powerglides are just dirt simple......Some of the light duty Powerglides were air cooled.....Had two big holes in the bellhousing & the converter had fan blades.
The Powerglide & TH350 are not Hydramatic Division units, The Powerglide was developed by Chevrolet & the TH350 was a joint venture between Buick & Chevrolet.
You've had bad luck. In 36 years, I've had only 1 fail and it was covered by warranty. (Chev 4L80E) They've all done fine typically with 120 to 140 k when sold and still performing well. I had a 99 Silverado that I sold to my secretary's husband. It has over 300k now. Doing fine. My Ford Transit is at 140k. No issues. Jeep WJ 115k. No issues.
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Same here. Never lost a transmission yet and I still have the one I got when I was 19. TH2004R out of an 87 Cutlass. That car rusted out years ago and the trans went in my 84 Cutlass to replace the factory 3 speed th250c. 270k miles on the trans now. 260k miles on another one. 200k on my truck 4L60E.
I recall the 180 was in the Chevettes. Were those the euro Opel trans? Chevettes bring back memories of broken crankshaft bolts, pulling the master cylinder to gain access to the starter, replacing ring and pinion under warranty, and warped front rotors. The car was JUNK. But right on the heels of that disaster was the X car - Citation. Unfortunately I was the only tech at our dealership sent to GM training on that junk. 11 recalls before it hit the showroom. Being on commission I had to really hustle to make a living in late 79 early 80.
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I recall the citation being junk but I always heard good things about the chevette. One kid in highschool tried to kill his and eventually lit it on fire instead when he got a new car. There were very few around by the time I was in the auto industry though, nobody would have taken good care of them for one thing.
I remember a young couple dropping off their friends 98 Subaru that blew a timing belt. They were driving around in a chevette as old us them, with a leaking rad. The leaking rad was the reason they were driving their friends Subaru when it died. They said the chevette never let them down, saw it driving around a few years after that.
My dad has a 2001 Supercharged Nissan Frontier he bought new. Original trans still in it with over 324,000 miles. After it sits it needs a bit of warm up time before it will go into drive. Once in drive there is no detectable slip and shift quality to me feels like new.
Its had many fluid drain and fills over its life with Dex 3
Its had many fluid drain and fills over its life with Dex 3
Have the 400 in my Jag XJS with the 12 cylinder.
'86 Chevy Nova ( Corolla ) 5 door hatch with 3 speed auto and 1.6 ltr. engine . 260,000+ miles . Used Slick 50 for automatics along with tranny fluid . Changed every 33,000 > 35,000 miles . Was told it was a MAZDA tranny by a transmission specialist . Was used for 3 different delivery routes and regular driving . Favorite all time car .
manicrodder
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I drove my 69 Mach 1 like a mad man and the C6 tranny never had a hiccup.
I grew up in a household where 4 teenagers learned how to drive and shared a Chevette and a Citation. The Citation was a much nicer car. Both were very reliable.
I’m now wondering if I should run the lubegard now as well or wait? I’ve heard it’s pretty good stuff.
AutoMechanic
Site Donor 2025
It is great stuff works like a charm. Ours was slipping and slamming into gear used the LubeGard and it was fixed instantly. If your transmission isn’t showing any issues I don’t know if I’d use it or not but I’m sure it won’t hurt to start using early.
I had never heard of lubgard shutter shock going to have to look into that for sure.
AutoMechanic
Site Donor 2025
Yep comes in a little tube good stuff. Used it in our other Ford too worked great in it as well.
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