Tape recording speed is ok, but playback speed is hapering

Without seeing the "disruption" it is difficult to say with confidence what the problem is. however, if the unit is sufficiently mis-aligned, the tracking information may not be read from the tape and that would cause the playback to be somewhat random. Since this is a digital recorder (as opposed to analog), the missing data can show up in really odd ways.

Does a tape recorded on this camera playback the same way? If so, then have the camera serviced paying particular attention to the alignment of the tape. If a tape recorded with this camera plays back on this camera OK but other tapes recorded elsewhere do not, it again points to alignment being off.

Check this and update this posting with the results.

Dan

This has been asked years ago but others can read this answer and look for themself if it worked.
The issue with these models of JVC are the cogs inside are made of white plastic that crack over time.
you can actually see the little tiny hair line if you take out the tape and gently turn the cog with a finger . Yes there are two cogs, it can be one or both.
The camera will try to play the tape , the tiny crack will misalign the speed or make it not possible to turn around as it is missing force and the camera will most likely give an error message .
The cogs can not be bought to fix. I have seen people write you can disassemble , use a cog calculator to print a brand new cog and so fix it. If you have a 3d printer etc etc.
I had no such luck.
Also there is a guide to shave a very fine piece of plastic on one of the teeth close to the crack, this should somehow rebalance the force, dont ask me how I do not understand the logic AND therefor not tested either. All I can say is I am still on the lookout for a new used minidv camera for my films but I will never ever buy JVC again because of this plastic story.

My source: I own jvc gr-d360E and it sucked.