Plow truck won't go into reverse

[DavidS]

I've got it buried in 3 to 4 ft of snow right now. It'll try to go forward but no reverse. I can't even see under the truck right now since it's so buried.

It's a 1988 Chevy K-5 Blazer that has been a plow truck for it's entire life and was used to plow the runway at Bradley Airport.

It was working OK for the last 8 times I've plowed with it, but always when I put it in reverse it would take 10 to 20 seconds for it to actually go into reverse. Now, it has no reverse at all.

Any ideas on what needs to be repaired?

[SLP IROC-Z]

probably a valve body issue

[Formula413]

Dumb question I know but the fluid isn't low right?

[DavidS]

probably a valve body issue

Thanks SLP!

[DavidS]

Dumb question I know but the fluid isn't low right?

When I put the new trans pan in, I put new fluid in. I've been checking it regularly and it always looks good.

I've been using the snow blower for the last 2 hours and barely made a dent. This sucks.

[Formula413]

Ugh, you've got a long driveway too. A bad valve body would probably make the most sense. I would think that if it were a clutch or a solenoid it would either work or not work. I'm far from an expert though.

[DavidS]

Ugh, you've got a long driveway too. A bad valve body would probably make the most sense. I would think that if it were a clutch or a solenoid it would either work or not work. I'm far from an expert though.
Thanks for the help Alex. I'm definitely not an expert, and I'll double check the fluid in the morning.


When I put it in reverse, I can hear the trans gears spinning, but the tires are not moving.

[SLP IROC-Z]

If it has Low gear it should have reverse. do the rest of the forward gears work?

[DavidS]

If it has Low gear it should have reverse. do the rest of the forward gears work?

It's a column shift automatic and when I put it in Drive, it tries going forward but the wall of snow in front is blocking it. Tires are spinning away though. I didn't try putting it in First or Second. I can go try in now though.

[DavidS]

In First & Second it's trying to move forward. It was able to move a few inches forward.

Could it be a problem with the rear end?

Underneath is packed with snow. I'll have to shovel it out in the morning to see if the drive shaft is turning.

[DavidS]

Drive shaft is not turning in reverse.

I added more ATF and now I'm way over the full line, but no luck.

[SLP IROC-Z]

are you hearing grinding noises in the trans in reverse?

[DavidS]

are you hearing grinding noises in the trans in reverse?

No. I checked closely today. No grinding noises. Reverse acts the same as Neutral.

[DavidS]

The trans is a TH700R4.

This might be a bone-headed question, but:

The bottom is packed with snow and ice. Are there are linkages that could be getting blocked and keeping it from going into reverse?

.....or is the transmission self contained and nothing outside of it can cause this problem.

[DAWG]

could be many things on that truck
but since you have fwd then that rules out the pump.
When you checked the fluid was it a Brown color and had a burnt smell?
could be the pressure regulator?
the clip can fall out and the regulator assy will be sitting in your pan.
best bet is to pull the pan and change filter and look for anything out of the ordinary.
if you were to drop the pan you'd have some fibrous material in it. looks like rebuilt time!
you could have a stuck reverse valve in the valve body aswell.
TV cable isn't broke? that will cause a few problems right there.
lets face it before you came along that truck was sitting for years.
Working under a truck in the middle of winter is no fun.
You might have to take it to a tranny shop for proper diagnosis.
I had a couple 700R4s at my brother in laws shop, Ill see if he still has them.

[Formula413]

The trans is a TH700R4.

This might be a bone-headed question, but:

The bottom is packed with snow and ice. Are there are linkages that could be getting blocked and keeping it from going into reverse?

.....or is the transmission self contained and nothing outside of it can cause this problem.

Probably not, but if it's like a 4L60E, which I assume it is, the linkage is on the side of the trans, and I guess it's not inconceivable that a chunk of ice could get in the way. But if that were the case I believe the shifter would not go into reverse. I would still suspect an internal problem like a valve body.

[DavidS]

Thanks Dawg and Formula!

Time to find a local transmission shop or a decent used TH700R4.

It looks like the problem is fairly common.

Pull it out, Probably something in the "reverse input drum"

Most common things that cause "no reverse"....
Cut seals on the reverse input piston.
Cracked reverse input drum, They crack at the weld.
Excessive reverse input clutch clearance.
Damaged Turbine shaft seals.

[DAWG]

any update on the truck David?

[DavidS]

No updates Dawg. The truck is still stuck stuck there.

My father-in-law suggested that I have AA Automatic Transmission in Canton CT tow it to their shop. As soon as some more snow melts, I have to take the plow off first.

AA Automatic Transmission web site: http://aa-automatictransmission.com/

[DAWG]

Ive heard good things about that place from others .
a free tow to the shop is nice too!.

[DavidS]

At $900, it's a little pricey but I'm thinking about buying this "Chevy 4x4 Turbo 400 Conversion Trans 700R4":

http://www.ebay.com/itm/Chevy-4x4-Turbo-400-Conversion-Trans-700R4-/141180781828?pt=Motors_Car_Truck_Parts_Accessories&hash=item20df07c504&vxp=mtr

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/QDYAAOxy79JRhTBE/$(KGrHqF,!qsFF71S+iH,BRhTBEI!ww~~60_57.JPG

Completely Rebuilt

Replace Your 700R4 Trans With a Heavy Duty Turbo 400

Has Special 27 Spline Output Shaft So You Don't Have To Change Your Transfer Case

This Trans Has The Same Overall Length as the 700R4, No Driveshaft Work Needed

Has Proper Adapter to Mate to Round Bolt Pattern 208, 241, 261

[ILuvPizzaTimes10]

Depending on our ECM the MIL might come on for Converter Lock Up solenoid IF that trans your getting doesnt have lock up? i dont know if its an inspected truck on the road? if not then who cares about the light. But other wise that will work IF they do in fact have the right output shaft.

[DavidS]

Depending on our ECM the MIL might come on for Converter Lock Up solenoid IF that trans your getting doesnt have lock up? i dont know if its an inspected truck on the road? if not then who cares about the light. But other wise that will work IF they do in fact have the right output shaft.

Hey Mike!!!! You're back. Cool!

It's not on the road. Ever. It's only for my driveway and I buy diesel with 5 gallon containers.

I'll have to look into the output shaft.

Thanks for the info!

[ILuvPizzaTimes10]

well from the description it sez it has the right one. But just make sure before you throw it in. the drive shaft will be the same splines. so put your drive shaft on the output shaft of the trans to verify it will fit the case before you go ripping everything apart. If you go that route.

[DavidS]

I just read online (not 100% sure if correct though) that:

87 or newer 700r4 has a 30 spline shaft

The truck is an 88, so it looks like it won't work. Thanks for catching that Mike!

If this is correct, I'll keep looking for another trans.

[ILuvPizzaTimes10]

the 700r4/4l60 and th2004r and th350 are all 27 spline. same drive shaft yoke. the th400 is 30. wich is why that th400 conversion needs the custom th350 output shaft for use in a 700r4 truck.

[DavidS]

the 700r4/4l60 and th2004r and th350 are all 27 spline. same drive shaft yoke. the th400 is 30. wich is why that th400 conversion needs the custom th350 output shaft for use in a 700r4 truck.

Hey Mike. Right now, I'm finishing off a Wachusett (Westminster, MA) Larry Imperial IPA so I could be easily confused. lol.

I have seen in a whole bunch of different posts online that "the 87 or newer 700r4 has a 30 spline shaft". I did Google searches on: 700r4 30 spline

Are you saying that I have a 27 spline shaft? If so, is there an easy way to confirm this?

[ILuvPizzaTimes10]

look up driveshaft yoke. every drive shaft yoke is listed at 27 splines for the 700r4 and th350. the INPUT shaft is the larger 30 spline over the 86-older 27 spline INPUT shaft.

[DavidS]

Ah OK. Thanks Mike!

So the only thing left to do is confirm that the INPUT shaft is 30 spline so that I don't have to buy a new torque converter?

[ILuvPizzaTimes10]

ohhh no haha now your getting to complicated. the trans HAS to come with a converter. or its just not worth it. the TH400 has a bigger output shaft then a 700r4 So a stock th400 wont fit your case. this one sez it has a "special" 27 spline output to fit your case. Just make sure when you get it is all youd need to do, some one may have NOT installed the right output for your app.

[DavidS]

the trans HAS to come with a converter. or its just not worth it.

Thanks Mike! It looks like it might not be worth it then.

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/jCsAAMXQ9MVRhTBO/$(KGrHqN,!rEFF9gfUiywBRhTBOWzIQ~~60_57.JPG

[DAWG]

You might just have to take it to the tranny shop and find out what is what?

[DavidS]

You might just have to take it to the tranny shop and find out what is what?

I keep thinking they'll want to repair it or replace it with another 700r4 and it'll cost between $2,000 to $5,000 by the time they're done.

I also keep thinking about when you said the 700r4 is probably not strong enough for the plow truck.

I talked to the EBay seller today. He rebuilt the th400 and said for an additional $100 he would include a rebuilt diesel torque converter.

I might go with this.

[frankzlt1]

that seems to be a lot for a stock rebuild dave.

[DavidS]

I've been looking on craigslist and ebay for a rebuilt 4x4 th400 but haven't found any much cheaper. This one is nice since it's a drop in replacement for a 4x4 700r4.

[frankzlt1]

Are you interested in rebuilding it yourself. I have a 4l60e from another f body the kit is $245. Have you looked into a 700r4 kit. Ill ask the guy that rebuilt my last 700r4 tomorrow. I know its from a diesel 6.2 I dont think theres that much of a difference other than the bell housing bolt pattern.

[DavidS]

Are you interested in rebuilding it yourself. I have a 4l60e from another f body the kit is $245. Have you looked into a 700r4 kit. Ill ask the guy that rebuilt my last 700r4 tomorrow. I know its from a diesel 6.2 I dont think theres that much of a difference other than the bell housing bolt pattern.

I'm not sure Frank. I saw that Monster has rebuild kits for about $500. Since I've never done it, it sounds like it might be a big project.

I've read up where some people have rebuilt their 700r4 every 8 months until they went to a th400.

Also, I can get the 4x4 th400 with converter for $950 shipping included. With a one year warranty.

[DAWG]

any updates David?

[My84Z]

Just get a cheap 400 converter and use that 400 converted trans.

[DavidS]

any updates David?

It's still stuck in my driveway, with no reverse, looking pathetic Dawg.

In the spring, I'll get the plow off.
http://img.photobucket.com/albums/v239/pratt1/IMG_20140222_123802_687.jpg

[DavidS]

Just get a cheap 400 converter and use that 400 converted trans.

I ordered the trans from the guy on EBay.

He has a shop called Brandi's Performance: http://www.jeeptruck.com/brandis/brandis.html (http://www.jeeptruck.com/brandis/brandis.html)

I'm not 100% sure, but I believe he builds stuff to order after he gets a sale. He is going to get put a rebuilt converter on.

He called and asked me to remove the cover and let him know how many bolts were between the converter and the flexplate. I froze my fingers digging the truck out and getting the cover off, but it looks like 3 bolts. I could only see 1 bolt, but he said it was either 3 bolts or 6 bolts. I put an arrow pointing to the bolt that I could see.
http://img.photobucket.com/albums/v239/pratt1/misc/flexplate-bolt.jpg

[DAWG]

any updates David?

[DavidS]

any updates David?

TH400 with 3 bolt torque converter (low rpm stall for diesels) is shipping out Monday.

[DAWG]

cool, driveshaft gonna work or do you need to get it shortend?
the th400 is much beefier than the 700r4.
btw how the shirt fit?

[DavidS]

cool, driveshaft gonna work or do you need to get it shortend?

According to the EBay ad, it should fit without cutting the driveshaft.
the th400 is much beefier than the 700r4.
Yep. Thanks for the recommendation!
btw how the shirt fit?
With the crappy weather, I need your newest set of tickets to Hawaii to try out the shirt. LOL.

[DAWG]

hehe get this, I flew there spent 2 days sitting on my hands.
They sent me back Friday!
Not ready for me yet lol.
gotta love the govt.
@ over 3 grand each time for tickets no wonder the deficit is so high!

[DavidS]

3K....Wow that's steep.

Kerrie wants to go someday and bring Alex but that could end up being a 20K week. Forget it.

[DAWG]

I get last minute tickets so that's where the high cost comes from .
You can get tickets for around 600.00 rt coach from Bradley a few months in advance.

[DavidS]

The 700r4 is now out and the TH400 is in place but I have a problem.

This is the old torque converter on the 700r4:
http://img.photobucket.com/albums/v239/pratt1/misc/flexplate.jpg

But, it looks like the spacing on the hole locations on the new torque converter are about 10" apart. It's hard to tell since it's in place.

I can't get the torque converter holes to line up with the flexplate holes!

I'm not sure what the problem is. Is the new torque converter the wrong one? Do I need a different flexplate?

[frankzlt1]

Now thats a wtf moment.

[My84Z]

See if they list different flywheels for a th400 or a 700r4 looks like you may need a flexplate also

[DavidS]

See if they list different flywheels for a th400 or a 700r4 looks like you may need a flexplate also

I think you're right.

I went to AutoZone today and ordered a $35.99 flexplate. They don't list the bolt spacing but hopefully this will work.


This product is a fit for your - 1988 Chevrolet Truck V10 Blazer 4WD 6.2L Diesel 8cyl
http://contentinfo.autozone.com/znetcs/product-info/en/US/pnr/FRA-143/image/4/

[DavidS]

See if they list different flywheels for a th400 or a 700r4 looks like you may need a flexplate also

You called it. I checked it this weekend and:

TH400 flexplate is GM # 14077157

700R4 flexplate is GM # 14077158



AutoZone has it as part number FRA-142
http://contentinfo.autozone.com/znetcs/product-info/en/US/pnr/FRA-142/image/3/

The teeth, the pitch and the OD size are all the same.
It's just the friggin bolt spacing to the torque converter that's different.
It looks like the TH400 converter is spaced apart by about an extra 1/2".
:sFun_bangdesk:

http://i.imgur.com/iWKad22.jpg

[My84Z]

That sucks but you got plenty of time to plow lol

[DavidS]

Update:

The th400 is in and the truck has been working great, except....the transfer case is leaking a lot of transmission fluid.

I think there might be a seal between the transmission and the transfer case that is screwed up.

[ILuvPizzaTimes10]

is it the case or the trans? the gasket on the housing adapter is the rear trans seal. the t case has an input seal and rarely leaks there.

[DavidS]

is it the case or the trans? the gasket on the housing adapter is the rear trans seal. the t case has an input seal and rarely leaks there.

It looks like it's coming from the transfer case but I'm not sure what part is leaking. It's a NP 208.

I keep filling the transfer case with trans fluid and I just put in another 1/2 quart.

[DavidS]

Mike...this is going to sound real off but I'm not sure what the fluid level is of the trans right now.

The th400 that replaced the 700r4 lines up totally different for the dipstick tube. I had a flexible braided line dipstick tube in, but it was impossible to read and eventually it just curled up and the dipstick won't even go in.

Anyway, after a few hours of putting three holes in the body, I'm pretty close to getting a shortened tube into the cab. True redneck trans fluid checking. lol. I can check it while I drive.

Anyway, I should know tomorrow how low the trans fluid is.

[DAWG]

NP208 were prone to stress cracking. I've learned also there was issues with it wearing from within. (see vid)
But I lucked out on mine years ago and had a seal leak.
https://www.youtube.com/watch?v=Nj5ZS8wOmNk

[ILuvPizzaTimes10]

yeah either pump grooves out the case or the chain wears threw the case. either way just keep it full for a part time truck.

[DAWG]

If it is the case a bit of JB weld works for awhile.
just clean the surface with brake cleaner and some scotch brite.

[DavidS]

Thanks Dawg and Mike!!!

It's been so cold in the old barn that I haven't been motivated to work on it the last few days. Very soon though, I should try to find out exactly where the leak is coming from.