Transmission Trouble

[boatbuilder]

Hello everyone, I've been a member for a long time but never had the need to post. There is so much helpful information I can usually find what I need. So I have an 85 M1008 here in Maine that I plow with. Its always run great and pushed snow like a beast. This past storm I got in, 5am, and started pushing snow. When I put it in Drive it acted like neutral, so I shifted down into 2nd and made a pass. Reverse was fine. Went to make a second pass, once again acted like neutral in Drive so went to 2nd and it did fine. Once I hit the snowbank that's where she stayed. No reverse, no action in any gear.
So I checked fluid, its clean and at the right level. The linkage all seems fine, column is deffinatly shifting the trannny. Truck has about 70,000 miles on it and I've never had a problem. Only thing I can think of is I had someone else plow for me while I was away earlier this winter and they confessed to putting it in reverse while still traveling forward and vice-a-versa because they were tight on time and wanted to get the plowing done. Would this wreck a tranny? And any thoughts on these symptoms? Im getting a rebuild quote of $1800. Also I've read the vacuum lines and modulator are known issues but would these symptoms be inline with those problems?
Any thoughts tips or advice would be great.
Thanks

 

[nyoffroad]

Sounds like a bad pump to me, either that or someone added Ford type fluid, that eat up the seals in older GMs.

 

[WWRD99]

Hello everyone, I've been a member for a long time but never had the need to post. There is so much helpful information I can usually find what I need. So I have an 85 M1008 here in Maine that I plow with. Its always run great and pushed snow like a beast. This past storm I got in, 5am, and started pushing snow. When I put it in Drive it acted like neutral, so I shifted down into 2nd and made a pass. Reverse was fine. Went to make a second pass, once again acted like neutral in Drive so went to 2nd and it did fine. Once I hit the snowbank that's where she stayed. No reverse, no action in any gear.
So I checked fluid, its clean and at the right level. The linkage all seems fine, column is deffinatly shifting the trannny. Truck has about 70,000 miles on it and I've never had a problem. Only thing I can think of is I had someone else plow for me while I was away earlier this winter and they confessed to putting it in reverse while still traveling forward and vice-a-versa because they were tight on time and wanted to get the plowing done. Would this wreck a tranny? And any thoughts on these symptoms? Im getting a rebuild quote of $1800. Also I've read the vacuum lines and modulator are known issues but would these symptoms be inline with those problems?
Any thoughts tips or advice would be great.
Thanks

Any chance you popped the transfer case into neutral?? If you go into D1 does it do anything? When you say no action does it just rev up like a clutch car with the clutch pushed in? As far as the other driver, it really depends on how much of a trans drop they were doing to figure if they did break something. Have you driven it since the other driver drove it and was it ok? Usually trans gear drops break or strip the planetary out and it doesn't move at all at that point...meaning they would not have made it home. The quote to rebuild doesn't sound bad at all but will be higher if hard parts are broken. The modulator does shifts not getting in gear and moving.

 

[87cr250r]

Not much to go wrong on the TH400. There is a piston that fails in the valve body but means no engine braking.

The NP208 transfer case shift forks wear out. They have a nylon bushing on them and once that goes the aluminum forks are toast slightly after. Neutrals everywhere. Put it in low range if you need to get it home.

 

[boatbuilder]

Any chance you popped the transfer case into neutral?? If you go into D1 does it do anything? When you say no action does it just rev up like a clutch car with the clutch pushed in? As far as the other driver, it really depends on how much of a trans drop they were doing to figure if they did break something. Have you driven it since the other driver drove it and was it ok? Usually trans gear drops break or strip the planetary out and it doesn't move at all at that point...meaning they would not have made it home. The quote to rebuild doesn't sound bad at all but will be higher if hard parts are broken. The modulator does shifts not getting in gear and moving.

Not much to go wrong on the TH400. There is a piston that fails in the valve body but means no engine braking.

The NP208 transfer case shift forks wear out. They have a nylon bushing on them and once that goes the aluminum forks are toast slightly after. Neutrals everywhere. Put it in low range if you need to get it home.

Thank you all for the input. I went home yesterday and tried it with the transfer case in all the different possitions 2, 4, 4L nothing. It acts like its in neutral (clutch car with clutch pushed in yes) everywhere in every gear with transfer case in any position.
I did plow with it after the other driver used it and it worked ok, maybe a little sluggish shifting but its hard to tell pushing snow.
Is my next move to drop the pan and see what can be seen? Any other diagnostics to do before digging in? Thanks again for all the knowledge and advice.

 

[WWRD99]

Thank you all for the input. I went home yesterday and tried it with the transfer case in all the different possitions 2, 4, 4L nothing. It acts like its in neutral (clutch car with clutch pushed in yes) everywhere in every gear with transfer case in any position.
I did plow with it after the other driver used it and it worked ok, maybe a little sluggish shifting but its hard to tell pushing snow.
Is my next move to drop the pan and see what can be seen? Any other diagnostics to do before digging in? Thanks again for all the knowledge and advice.

I would think basic stuff like check fluid level, I don't think color would be an issue if you broke a hard part inside, make sure the transfer case linkage didn't fall off and not work the gears....weird stuff happens...have someone put it in gear with the feet on the brakes and see if you can hear anything out of the trans or transfer case...like whining or grinding...check the trans linkage to make sure it is going on the rooster tail inside and clicks solid...make sure the transfer case has fluid...that's about all you can do if you are not going to rebuild it yourself. You could check line pressure if you had a gage to do so. You can pull the pan and look for chunks but that would be the last thing I'd do.....very messy job that always ends up with fluid everywhere and won't tell you much.