Chevy automatic tranny
Discussion
Well, it all started on the weekend, when my daily driver truck (1989 chevy C1500 half ton) decided it wouldn't go into reverse or park anymore. :sigh:
Since the last time I had the tranny out wasn't long ago, and I didn't have a great experience with the tranny shop, I figured I'd give it a go this time.
Whooee! there's lots of parts in those things! All in all, not too bad, I only have to figure out where 1 or 2 of the balls in the valve body are supposed to go. It ended up that the low/reverse clutch, which is essentially an over-run clutch (freewheels in one direction, drives in the other), that looks like a bearing had disintegrated the cage, sending shrapnel through the tranny, and physically blocking the linkage. It also managed to crack the 3/8" thick inner race! Chev small block torque is cool, but bad sometimes...
I still have to read some more to figure out how the hell it actually works, but it isn't that mechanically complicated. I certainly won't send one out again.
Hmm, doesn't seem to be any real point to this post, does there? Ah well, I found it interesting, so thought I'd share. Your welcome.
Gary
Since the last time I had the tranny out wasn't long ago, and I didn't have a great experience with the tranny shop, I figured I'd give it a go this time.
Whooee! there's lots of parts in those things! All in all, not too bad, I only have to figure out where 1 or 2 of the balls in the valve body are supposed to go. It ended up that the low/reverse clutch, which is essentially an over-run clutch (freewheels in one direction, drives in the other), that looks like a bearing had disintegrated the cage, sending shrapnel through the tranny, and physically blocking the linkage. It also managed to crack the 3/8" thick inner race! Chev small block torque is cool, but bad sometimes...
I still have to read some more to figure out how the hell it actually works, but it isn't that mechanically complicated. I certainly won't send one out again.
Hmm, doesn't seem to be any real point to this post, does there? Ah well, I found it interesting, so thought I'd share. Your welcome.
Gary
Well you will need to put a new torque convertor and flush all the cooler lines as they are likely to be full of metal. Also strip and clean the front pump and valve body. This forum is excellent for info and help on GM trannys:
www.hotrodders.com/forum/transmission-rearend/
I have this book which is very good also:
www.amazon.com/Turbo-Hydra-350-Hp511-Sessions/dp/0895860511
www.hotrodders.com/forum/transmission-rearend/
I have this book which is very good also:
www.amazon.com/Turbo-Hydra-350-Hp511-Sessions/dp/0895860511
Ah, I knew there was a reason I put this up here. I would have completely forgotten the cooler lines. Thanks.
I went to the library and borrowed a couple of tranny books, this is a 700R4 (4L60 in new speak), so pretty similar to the TH350/400 series, but 4 speed w/ lockup converter.
So far I'm in for $CAN90 worth of bits & gaskets, a fair bit better than last time I took a tranny in to get worked on ($1300). Around here it seems like auto tranny shops think they can do/charge whatever they want, as not many people are willing to dive into one. Guess I'll see if it's worth it or not once I try to put it together and back in!
The engine needs a rear seal anyway, which has been bugging me for awhile, but it's easy to do it now.
Next update later tonight.
Gary
I went to the library and borrowed a couple of tranny books, this is a 700R4 (4L60 in new speak), so pretty similar to the TH350/400 series, but 4 speed w/ lockup converter.
So far I'm in for $CAN90 worth of bits & gaskets, a fair bit better than last time I took a tranny in to get worked on ($1300). Around here it seems like auto tranny shops think they can do/charge whatever they want, as not many people are willing to dive into one. Guess I'll see if it's worth it or not once I try to put it together and back in!
The engine needs a rear seal anyway, which has been bugging me for awhile, but it's easy to do it now.
Next update later tonight.
Gary
gary_tholl said:
this is a 700R4 (4L60 in new speak), Gary
Very familiar with them - full details of how to rebuild them can be found on my site:
www.mez.co.uk/Chevy700r4pg2.html
Edited by eliot on Tuesday 9th January 22:39
eliot said:
gary_tholl said:
this is a 700R4 (4L60 in new speak), Gary
Very familiar with them - full details of how to rebuild them can be found on my site:
www.mez.co.uk/Chevy700r4pg2.html
Cool, thanks!
I got the majority of the insides back in now. Just need to put the pump on, and the valve body stuff, then it goes back in. So far it hasn't been bad at all, I don't expect any problems with the next few steps either, so should be ok.
Great webpage! wish I'd found it a few days ago, would've saved me a sleepless night wondering if I was going to be going to a shop with a bucketful of parts!
Hopefully I'll post later tonight with it all put back together and working again.
Gary
Well, the tranny is all back together and sitting beside the truck. I didn't feel like putting it back in last night, and need a couple of exhaust bits anyway.
It all went back together quite nicely. The only issue I had was that I put the pump in, which moved the drum and 2-4 band, which didn't allow the 2-4 piston to go in properly. I pulled the pump, then the 2-4 piston would go in right, but then I couldn't get the pump back in. grrr. Ended up getting the pump halfway in, then wiggling the band with a screwdriver to get the piston in the right spot. Also replaced the rear seal on the engine, so hopefully it will hold it's oil a little better now as well.
Managed to figure out all the check balls in the valve body, pretty amazing when you think somebody actually figured all of that out and made it work!
Should have it back in the truck tonight and see if it works. Here's hoping!
It all went back together quite nicely. The only issue I had was that I put the pump in, which moved the drum and 2-4 band, which didn't allow the 2-4 piston to go in properly. I pulled the pump, then the 2-4 piston would go in right, but then I couldn't get the pump back in. grrr. Ended up getting the pump halfway in, then wiggling the band with a screwdriver to get the piston in the right spot. Also replaced the rear seal on the engine, so hopefully it will hold it's oil a little better now as well.
Managed to figure out all the check balls in the valve body, pretty amazing when you think somebody actually figured all of that out and made it work!
Should have it back in the truck tonight and see if it works. Here's hoping!
Yippee... it's in and works like a charm. It really wasn't as hard as I thought it might be, all went quite well.
Thanks for the tranny info. I'm just reading up on the theory of how they work, never really looked too closely at them before.
Next up will be re-programming the ecu, and I think I have a dodgy head gasket on one side. Sigh. Next week.
Gary
Thanks for the tranny info. I'm just reading up on the theory of how they work, never really looked too closely at them before.
Next up will be re-programming the ecu, and I think I have a dodgy head gasket on one side. Sigh. Next week.
Gary
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