Diagnostic help

[Deaken]

I've got a 1985 GMC Jimmy (K5 Blazer) that I pull my pop-up camper with and we were headed back from a Tn state park when I noticed something felt wrong. It felt almost like I had a tire going flat. Luckily I was at my exit when I pulled off. I stopped along the side of the road check them all nothing low, lose, or scrubbing so I think to myself maybe it was the road got a little bumpy and it got into an awkward bounce I take off and 1st-4th was smooth but once it got into overdrive it started surging. I was afraid that the transmission was slipping ar first and stopped at a gas station to check the fluid level was good didn't have an awkward smell so I push to get home. Once I got home I was turning it around and noticed that when in drive or reverse it has a wicked ruff idle but in park or natural it idles fine so it makes me think it's the torque converter. Is there any way to check before I buy a $200+ dollar part and take the tranny out? Thanks,

 

[41mag]

If you have the 700-r4 trans ( most do if it's an overdrive) they have a "lock up " type converter. There is a torque converter clutch solenoid that allows it to engage into full lock up on hwy speeds. It may be that it's getting stuck. It would seem like it's constantly "straining " when you put it in gear, thus causing excessive load on the engine.
Consult a repair manual on exact location and diag. procedure. I would check this before I pulled trans.
Good luck !

 

[Deaken]

It has a 700R4, the previous owner (my uncle) got to rebuild it when it crapped the tranny.

 

[Boost Freak]

If you have the 700-r4 trans ( most do if it's an overdrive) they have a "lock up " type converter. There is a torque converter clutch solenoid that allows it to engage into full lock up on hwy speeds. It may be that it's getting stuck. It would seem like it's constantly "straining " when you put it in gear, thus causing excessive load on the engine.
Consult a repair manual on exact location and diag. procedure. I would check this before I pulled trans.
Good luck !

Where is the solenoid and how can we check it as I will be helping with the repair.

 

[Zombie Ninja]

You're not supposed to use overdrive while towing.
Its a lot of gear stress and a torquey motor or a diesel will snap a tranny shaft pretty quick.
Sounds like you've got problems already though.

 

[Deaken]

You're not supposed to use overdrive while towing.
Its a lot of gear stress and a torquey motor or a diesel will snap a tranny shaft pretty quick.
Sounds like you've got problems already though.

Camper and gear is less than 3,000 pounds so I didn't think it was a big deal but I guess it could have been.

 

[Deaken]

TTT

 

[georgia357]

You're not supposed to use overdrive while towing.
Its a lot of gear stress and a torquey motor or a diesel will snap a tranny shaft pretty quick.
Sounds like you've got problems already though.

I know this is not going to do the OP any good but it might just help somebody else from doing it. I learned the hard way, burnt up the transmission in my Trailblazer towing a small camper in overdrive. Good luck with yours Deaken.

 

[Bucket]

Toasted mine, years ago, hauling an empty trailer in od. Same set up but an 84 k-5. Did something to the torque converter, but I kept driving and eventually toasted the tranny.

 

[8675309]

vacuum modulator could have a leak,that would explain the rough idle and surging in between shifts.
many factors there. have a pro diagnose it.