Transmission gear shift delay? Play in U Joints?

[76k5blazerr]

So guys my truck when you shift it from park to reverse or drive or 2 or 1 (low gears) it clunkes in to gear, like you throw it in gear and there's about a 1 second delay before the rpms drop. I know it's not a transmission problem because this th350 is freshly rebuilt by a reputable shop with maybe 1500 miles on it. Also does it when going from drive to reverse or vise versa. I've had several people tell me it's the driveshaft u joints, I replaced the front u joints a few months ago but lord knows how old the rears are. Another thing that clues me to the u joints is when I'm in reverse, backing up a hill and sometimes on flat ground if I do anything but let it idle backwards in reverse I feel the truck vibrating like its coming from underneath. What do yall think?

 

[rebelgregory]

U-joints are a likely culprit. But they have nothing to do with the delay shifting into gear. If the delay is abnormally long, it's a tranny/fluid/line pressure issue. However, some delay seems to be normal in my experience.

 

[Deuling]

The delay doesnt sound too crazy, I agree if its anything really abnormal, probably trans pressure related.

The clunk could be multiple things. U joints, bad or old engine or transmission mounts, even something like a bad spring bushing, or anything to a broken center pin in the leaf packs or U bolts loose. There is some play somewhere.


I know mine used to clunk bad when going into gear, I replaced the old transmission mount (very cheap) even though the old one looked OK, it was old, and old mounts dont work as well as new.

Although my clunk came back, only for me to find that one of my engine mounts was shot and the clamshell was on the frame thing the mounts bolt to.

If a mount is bad, I could see it helping the delay seem worse, as the engine and transmission are going to twist a little more until you feel the axle engage.

 

[76k5blazerr]

Yah the delay sounds normal. I'm gonna replace the rear shaft u joints as soon as I can

 

[Deuling]

If they are really that worn, push up and down on the drive shaft at both ends, if you have play then yes its worn.


But depending on how old everything is, im willing to bet the trans mount is shot unless you replaced it recently.

 

[diesel4me]

All the above could be the culprit...

Also,the rear end could have slop in the spider gears if its non-posi...try turning the driveshaft by hand in neutral (wheels chocked) and feel how far it'll turn before you feel resistance--it may have a lot of backlash in the ring & pinion or the spiders are getting sloppy..make sure the spring u-bolts are tight too..

 

[76k5blazerr]

Where can I find a new transmission mount? Picked up U Joints today, gonna install them tomorrow morning. I'll let yall know if they help. I'm thinking my tranny mount is shot because now I'm occasionally getting a clunk when the tranny shifts gears. Checked my tranny fluid by the way and its filled to the proper level. Thanks

 

[Deuling]

Got mine at Oreillys I believe. Wanna say it was like $10-$20 range

 

[76k5blazerr]

Ok I'll check it out, is it just called "transmission mount"?

 

[76k5blazerr]

Found them at oriellys. Do you recommend replacing the upper and lower tranny mounts? And how hard is it to replace them. I removed and reinstalled the tranny and t case in this truck but never done a tranny mount before.

 

[Deuling]

Id do both.

And its as easy as putting a jack on the pan, and removing what, 4 bolts I think?

Remove bolts, jack the trans up a bit, tilt the old one out the back, put new in.


Just make sure if you have rubber engine mounts, get a rubber trans mount. Don't run a poly trans mount and rubber engine mounts. Recipe for a cracked trans housing.

 

[76k5blazerr]

Ok, I'm not sure if my engine mounts are rubber or poly. Any way to check? And know my tranny is clunking when it changes from 1st to second gear. Think that's tge mount or what? I really don't need tranny problems right now...

 

[Deuling]

Ok, I'm not sure if my engine mounts are rubber or poly. Any way to check? And know my tranny is clunking when it changes from 1st to second gear. Think that's tge mount or what? I really don't need tranny problems right now...

Just get rubber. Thats the safest bet at the trans.

 

[kennyw]

Stock engine mounts are rubber. 99.9% of all the trucks out there still have stock style mounts.

 

[76k5blazerr]

Do you think the mounts will fix the clunking I just described?

 

[Deuling]

Do you think the mounts will fix the clunking I just described?

If they are bad/ old it can only help.