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Discussion Starter #1
I have just replaced the A670 in this 93 Caravan with what appeared to be a "used" rebuilt A670, that was included in the sale of the van.
The original transmission had what appeared to be many needle bearings and at the bottom of the pan. That old transmission was removed and replaced with the "spare" A670 with near new looking T.C. After considerable time taken to re & re the transmission, carefully seating the TC onto the pump and buttoning up the trans. it's clean pan was inspected with no debris and a clean magnet. I could see that there was a newer Sonax reverse band strut beside the valve body. This give me some assurance that it had been worked on. Fresh ATF was carefully filled and vehicle shifted correctly in all gears. THe van drove beautifully.

But today was a different story. Today she reversed out of the garage, someone took it out for a 5 minute test drive, with correct shifting. When they returned, there was no reverse!!!!!!

The fluid was check and a small amount was added. There is not fluid leaking. Linkages seem correct but no reverse.

Now what? I took on this project with the assurance that the spare trans was good. And perhaps it still is.

Any suggestions before I swap this out.

Thanks in advance

Aldergrove
 

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If the torque was not right on the reverse band it can break either the band or linkage. Try adjusting the torque first with a 1/4 inch torque wrench. It may have been too loose.
 

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It could be the reverse band strut fell out from the band being too loose. Drop the pan and look for the liitle strut. I have heard that those can be put back in by removing the valve body and fitting it back in-place followed by correctly setting up the reverse band.
 

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Discussion Starter #4
John Wood said:
It could be the reverse band strut fell out from the band being too loose. Drop the pan and look for the liitle strut. I have heard that those can be put back in by removing the valve body and fitting it back in-place followed by correctly setting up the reverse band.
The sonax reverse band strut remained in position. The pan was drained and dropped to reveal a broken reverse band end. What a pain. I do have two other cores here that may have good reverse bands, but the job to open up and remove the guts of these units would take time. So I am looking for another A670 for this 93.

Hollander does say 87 - 93 A670's will interchange as a direct fit. In the past, I have successfully swapped in a 96 A670 into a 93 Voyager without issue!. So.. I am wondering if I can go further and find 94- 98 A670;s in Caravan/Voyager or other applications that will work just as well. I don't think my 93 will notice the difference. IT does not use a Crank PS on the bell housing or have ABS or have the additional rear mount requirement.


YOur thoughts???/
 

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Aldergrove said:
The sonax reverse band strut remained in position. The pan was drained and dropped to reveal a broken reverse band end. What a pain. I do have two other cores here that may have good reverse bands, but the job to open up and remove the guts of these units would take time. So I am looking for another A670 for this 93.

Hollander does say 87 - 93 A670's will interchange as a direct fit. In the past, I have successfully swapped in a 96 A670 into a 93 Voyager without issue!. So.. I am wondering if I can go further and find 94- 98 A670;s in Caravan/Voyager or other applications that will work just as well. I don't think my 93 will notice the difference. IT does not use a Crank PS on the bell housing or have ABS or have the additional rear mount requirement.


YOur thoughts???/
Assuming that the tranny you just put in had been rebuilt with new clutches and seals, and the only thing wrong is a broken rear band..... I'd just replace the rear band. It appears that the rebuilder just replaced the low/reverse band strut and tightened the band up to hold the clutch drum in-place while assembling the rest of the guts, but forgot to set the band up with the proper torque and backed-off turns. He either forgot or just assumed the installer would set the bands. It is usually a good idea to check the settings anytime the pan and filter is off.... although you rarely run into one that is too tight, unless someone has messed with it.

As far as finding another used tranny, you pretty much know the routine from previous experience. I'd stay with a mini-van tranny and avoid the car tranny's because of the slight gearing differences. They will all work however.
 

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Discussion Starter #6
Thanks for your help guys!

When reassembling the A670 after new band is installed.... how does one keep the 8 overun clutch rollers + 8overrun clutch springs from travelling out of position? I do not own the loading tool : L -4440 which is recommended to be used in the ATSG rebuild manual. IS there another method????
 

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Discussion Starter #7
Just reviewing this old post of mine and I never did update.

I pulled the A670 which was easy. I drained and opened the tranny, unpacked the assemblies and extracted the broken reverse band. The new reverse band was installed and initially installed in the ballpark until assembly was completed. Using Chrysler torque settings, the band strut was perfectly set.

Hold the 8 overrun clutch rollers and 8 springs was simple!!!!!

I loaded the assembly with plenty of Vaseline petroleum jelly. Worked like a charm! The jelly prevented any unnecessary movement and the clutch went home without any issues.

I would like to try rebuilding an A604 next!

Thanks again guys.
 
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Just reviewing this old post of mine and I never did update.

I pulled the A670 which was easy. I drained and opened the tranny, unpacked the assemblies and extracted the broken reverse band. The new reverse band was installed and initially installed in the ballpark until assembly was completed. Using Chrysler torque settings, the band strut was perfectly set.

Hold the 8 overrun clutch rollers and 8 springs was simple!!!!!

I loaded the assembly with plenty of Vaseline petroleum jelly. Worked like a charm! The jelly prevented any unnecessary movement and the clutch went home without any issues.

I would like to try rebuilding an A604 next!

Thanks again guys.
Thanks for the update and glad it all worked out.
 

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Discussion Starter #10
Are the 604's nasty to rebuild?
 

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From what I've read the A604/41TE is a complex transmission and require special tools to rebuild.
 
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