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Author Topic: No reverse  (Read 5660 times)

Offline juicekohl21

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No reverse
« on: January 17, 2015, 04:12:13 pm »
I have an 1987 Gmc 1/2 ton 4x4 regular cab with a 350 fuel injected and I swapped the 700r4 tranny and transfer case for a T400 and larger transfer case which has 2H-2L 4H-4L which came out of a 78 Gmc.  I also swapped out the diffs seeing as how it was a 3/4 ton i figured bigger diff with lower gear ratio seeing as how I'm running 35" tires for a hunting truck would be good. It is an automatic I got the kick down to work fine but when I put it in drive or reverse it almost stalls and sometimes it will, and I have no reverse.  It engages rocks the truck a tiny bit but will only back up if I am on my level concrete floor and it makes an almost wining sound.  Not sure what is wrong?
« Last Edit: January 17, 2015, 05:24:18 pm by juicekohl21 »
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Offline LTZ C20

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Re: No reverse
« Reply #1 on: January 17, 2015, 08:36:59 pm »
My first thought is, if it engages but makes a whining noise, reverse is gone.
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Offline juicekohl21

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Re: No reverse
« Reply #2 on: January 17, 2015, 08:56:38 pm »
It seemed to back out of my shop fine but not once it was hot it was a no go.  Wasn't sure if the torque converter would do that or not seeing as how it pulls down the engine so much?
« Last Edit: January 17, 2015, 09:26:44 pm by juicekohl21 »
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Offline Irish_Alley

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Re: No reverse
« Reply #3 on: January 18, 2015, 12:13:41 am »
is your fluid level right? about the stall whats your idle rpms at?
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Offline LTZ C20

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Re: No reverse
« Reply #4 on: January 18, 2015, 01:04:24 am »
Transmissions can have different behaviors based on fluid temperature. My old 350 did the opposite. When it crapped out, bone cold it wouldn't move an inch forward or back,  let it idle for awhile and start to warm up, would move a little, longer engine ran, hotter trans got, better it worked. First thing to check is if your fluid is at the proper level.
« Last Edit: January 18, 2015, 01:07:06 am by LTZ C20 »
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Offline juicekohl21

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Re: No reverse
« Reply #5 on: January 18, 2015, 10:03:54 am »
I did check the fluid it is good.  As for the revs i don't have a tack so I'm unsure but it sound like a high idle not sure why it wants to stall.
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Offline VileZambonie

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Re: No reverse
« Reply #6 on: January 18, 2015, 10:29:45 am »
Do you know if this trans ever worked before you put it in? There is no kickdown on a 700R4 it uses a Throttle Valve cable (TV cable). If everything is correct including fluid level and you probably have a sheared sunshell.
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Offline juicekohl21

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Re: No reverse
« Reply #7 on: January 18, 2015, 10:38:30 am »
It was my father inlaws truck which has been parked for a couple years but was his hunting truck that he had with no issues, when i asked him.
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Offline 78BIG-TEN

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Re: No reverse
« Reply #8 on: January 18, 2015, 02:46:08 pm »
If I understand right you put a Th400 in it.No reverse on a 400 could be rear band or servo.If it drives forward put in low and accerate then let off gas and see if trans tries to slow it down.If just coasts like neutral I would drop the pan and look at the servo cover gasket and servo
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Offline juicekohl21

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Re: No reverse
« Reply #9 on: January 18, 2015, 03:30:04 pm »
It does slow its self down.
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Offline 78BIG-TEN

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Re: No reverse
« Reply #10 on: January 19, 2015, 08:47:03 am »
and tou have all forward gears or does 3rd not work
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Offline juicekohl21

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Re: No reverse
« Reply #11 on: January 19, 2015, 11:02:11 am »
I only took it for a short drive down my driveway but now that you say that it did seem to be revving quite high i just thought it was on the verge of shifting when i had to slow down.
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